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November 30, 2009

2009 Atlantic hurricane season ends today

The Atlantic hurricane season ends quietly today, with no lingering activity anywhere in the basin.

NOAA says it was the slowest season since 1997 in terms of the number of named storms and hurricanes.  

The final tally? Nine named storms (Ana through Ida), of which three became hurricanes. Two of those made it to "major" status of Category 3 (111 mph winds) or higher. There were also two tropical depressions that never became strong enough to earn a name.

The big players were Hurricanes Bill, Fred and Ida

Bill grew to Cat. 4. It was linked to two deaths - a 54-year-old man who died in storm surf in Florida, and a 7-year-old Maine girl who was swept from rocks at Acadia National Park by a storm wave.

Fred impressed only the meteorologists. It stayed far out in the eastern Atlantic and blew up to Cat. 3 before it expired. It turned out to be the strongest hurricane on record south of 30 degrees North latitude, and east of 35 degrees West longitude, and only the fourth known storm to reach Cat. 3 in that part of the Atlantic. But hardly anyone noticed.

Storm Ida at Ocean City, NJIda killed more than 150 people in El Salvador alone before it moved from the northwest Caribbean into the Gulf of Mexico. It reached Cat. 2 strength over the Gulf, but went ashore in northwest Florida as a tropical depression. Its remnants contributed to a destructive low that formed off the southeast Atlantic coast. The resulting three-day nor'easter caused significant flooding and beach erosion from the Carolinas to New Jersey, including Maryland.

Ida was blamed when three New Jersey fishermen perished as their boat sank in rough seas. Three motorists died in weather-related crashes in Virginia. A 36-year-old surfer died in rough waves in New York, and an elderly man died in North Carolina when a tree fell on him in his yard.

While two storms brought tropical-storm-force winds to the U.S. mainland, no one experienced hurricane winds. It was the first time in three years that's happened, NOAA said.

So how did the prognosticators do? The season proved less active than the springtime predictions had suggested. Most forecasters guessed high based on long-range cyclical factors in the Atlantic that have boosted storm formation since 1995. But they lowered their expectations as a developing El Nino event in the tropical Pacific promised to suppress hurricane development in the Atlantic. The season turned out to be below the long-term averages.

Here's the scorecard, based on the spring forecasts:

Average:  11 named storms; 6 hurricanes; 2 "major" storms. 

Actual: 9 named storms, 3 hurricanes, 2 "major" storms.

NOAA (May forecast): 9-14 named storms; 4-7 hurricanes; 1-3 "major."

Colorado State U. (April):  12 named storms; 6 hurricanes; 2 "major."

WeatherBug (April): 11-13 named storms; 6-8 hurricanes; 3-4 "major." (March): 13 named storms; 8 hurricanes; 2 "major."

The first long-range forecast for the 2010 Atlantic hurricane season will likely come in December, from the folks at Colorado State University.

(AP PHOTO/Vernon Ogrodnek/Ida's remnants rake Ocean City, N.J.)

Posted by Frank Roylance at 10:56 AM | | Comments (1)
Categories: Hurricanes

November 29, 2009

Will we get snow on Dec. 5?

It's that time of year again, when the WeatherBlog speculates about the chances for snow on Dec, 5. Why Dec. 5?

Well, because we've noticed a curious pattern - or coincidence - about some of the earliest snowfalls in Baltimore. It's just this: In five of the last seven years, Baltimore-Washington First snow WeatherDeckInternational Thurgood Marshall Airport has recorded snow - at least a trace of snow - on Dec. 5. And it's snowed in six of the last seven years if you fudge the criteria a bit and include Dec. 6.

Here are the stats:

2008:  None  (but we got 0.6 inch on the 6th)

2007:  4.7 inches

2006:  Trace

2005:  1.4 inches (and another 1.9 inches on the 6th)

2004:  None (something went terribly wrong)

2003:  3.0 inches (and another 3.8 inches on the 6th)

2002:  7.4 inches (and a trace on the 6th).

Okay, so there's probably no real science attached to this. Call it folklore. Local folklore (it sounds nice coming off the tongue). But it fits in nicely with the season, and our inevitable anticipation of the first snowfalls.

That said, the long-range forecast for Saturday (the 5th) is not very promising: Mostly sunny with a high of 42 degrees. We may need to call for a pajama campaign to pull it off this year. Kids? Better turn those jammies inside-out this week.

If anyone has some other family snow charms that have worked for you in the past, let's hear about them. Looks like we're going to need them this year.

Posted by Frank Roylance at 8:07 AM | | Comments (9)
Categories: Winter weather

November 25, 2009

44-foot waves, 203-mph gusts; Typhoon Nida roars

NASA NidaWhile we watch the Atlantic hurricane season wheeze to a close, the Pacific continues to be a fearsome storm factory.

Up next is Typhoon Nida, left, now 150 miles west southwest of the U.S. territory of Guam. The storm has reached Cat. 5 strength, a Super Typhoon. Top sustained winds are blowing at 172 mph.

For now, no large land masses are threatened, although a number of small islands near Saipan are being affected. Here's more on Nida from NASA

Here's a forecast map from the Navy. Here's the forecast discussion.

Posted by Frank Roylance at 5:13 PM | | Comments (2)
Categories: Hurricanes

Bad travel day should improve. A little.

"Expect tough going at the major airports this morning," forecasters said. The region remains stuck in a pattern of rain, drizzle, low clouds and fog as a high pressure center over New England continues to shove cool, wet air onshore and up against the eastern slope of the Appalachians.

"This will greatly hamper movement at all three major airports today," the forecasters' morning discussion warned. "If you want to look on the positive side, no airport [or] highway on the east coast will experience wintry weather on this busy travel day."

Baltimore fogNot today, maybe, but Sterling is still predicting rain mixing with and changing to snow in the higher elevations of Maryland's western counties on Thanksgiving, and it could start accumulating overnight into Friday in some spots.

North and northwest winds and moisture off the Great Lakes are likely to yield a "prolonged upslope snow event through Friday night before winding down Saturday," they said. "Confidence is increasing in Winter Weather Advisory level snow accumulations [less than 4 inches] across the favored western slopes, but still too far out to nail down snow totals."

So far, the incessant dripping has left 1.11 inches of rain in The Sun's gauge since Monday. The airport has recorded just over 1.5 inches. 

Looking for good news? Well, forecasters do expect this soup to thin a little later today, with the chance we'll see a few stars tonight before the next coastal low brings us two more days of gray, wet weather. Then, as the low departs and winds become more westerly for the weekend, look for moderating temperatures and drier weather. Really.

(SUN PHOTO/Jed Kirschbaum 2008)

Posted by Frank Roylance at 11:15 AM | | Comments (0)
Categories: Forecasts

November 24, 2009

NASA detects "tsunami" on the sun

NASA solar tsunami 

Tsunamis on the Earth can be terrifying enough - a wall of ocean water surges inland after being set loose by an undersea earthquake, and crushes all in its path. Hundreds of thousands died in the December 2004 tsunami (astonishing video below) that originated in Indonesia.

But imagine a tsunami of hot plasma that is 62,000 miles high, travels at half a million miles per hour and packs the power of 2,400 megatons of TNT. That's what scientists have discovered on the sun.

Solar tsunamis are harmless to life on Earth. But understanding them - and being able to spot them - may help solar scientists better predict and anticipate the effects of coronal mass ejections and other eruptions on the sun that can and do affect human communications, power grids, satellites and other systems on and around the Earth.

NASA's twin STEREO spacecraft recorded a solar tsunami in February of this year, and produced two movies of the event, taken from two different angles. The discovery allowed scientists to confirm the theory that had been proposed in 1997 when another spacecraft, called SOHO, spotted what looked like a solar tsunami, but which some thought might be something else.

You can read more about this phenomenon here.

Posted by Frank Roylance at 5:32 PM | | Comments (2)
Categories: Science

Snow/rain mix possible here Friday night

As if the weather outside your window weren't gloomy enough, now forecasters out at Sterling have inserted the words "rain/snow mix as far east as I-95" into their morning forecast discussion.

That prediction is for Friday night, as a low-pressure system spinning counter-clockwise over New England pulls cold air into our region on north winds. It's the first mention this season, I think, of the possibility of flakes in the air in Central Maryland. And so, it begins.

Rain on I-83Before we get to Friday, of course, we are looking at more rain, drizzle and fog, at least into the early afternoon today. That's the doing of a coastal low that is now moving away from the region.

Weak high pressure is building into the region already, but it is not expected to drive off the low cloud cover. Drizzle and rain may persist overnight near the bay, while diminishing farther west.

The next coastal low is expected to develop Wednesday. This one appears likely to stay farther off shore, but forecasters say we will remain in line for still more showers and drizzle into Thanksgiving Day.

It's the passage of the next cold front that will turn our weather colder and breezier by late Thursday and Friday. North winds and dropping temperatures are forecast to change rain to snow in the Potomac Highlands late on Thanksgiving Day, and to a rain/snow mix as far east as the Blue Ridge.

By Friday night the cold air will have made it to Central Maryland, with an overnight low around 35 degrees Friday into Saturday. That's when we may see some snow mixed in with our rain.BWI/Nov. rain

Farther west, the snow will start to accumulate, and the National Weather Service is expressing "increasing confidence" in a need to issue some Winter Weather Advisories for Maryland's western counties by then. If you're driving west for Thanksgiving at Deep Creek Lake, or Pittsburgh or to visit relatives in West Virginia, pay attention to the forecasts.

Sunshine? You want sunshine? Hang on until the weekend. We should see some blue sky on Saturday. Sunday and Monday look better, too. Then the next storm system moves in.

Posted by Frank Roylance at 10:48 AM | | Comments (2)
Categories: Winter weather

November 23, 2009

NWS: Moderate El Nino winters can be Md.'s snowiest

For those readers hoping for a snowy winter this year after a series of disappointments, there is hopeful news Monday morning out of the National Weather Service's Sterling forecast office. (Likewise, for those who loathe the ice and slush, dangers and inconvenience of wintery weather, these will be discouraging words.)

Forecaster Jared Klein has done a statistical analysis of winters since 1950 and has found 17 winters that were influenced by the El Nino phenomenon in the tropical Pacific, like this one is expected to be. The long and short of it, says Chris Strong, also at Sterling:

NOAA/NWS"With moderate strength El Nino's [like this one] we have statistically the greatest chance of above-normal snowfall."

What they're saying is that not all El Nino winters are alike for the mid-Atlantic states. Some will be snowy; some not. Here's how they tend to break down, according to Klein:

* On average, weak El Nino winters bring below-average temperatures and below-average precipitation. Not generally conducive to lots of snow.

* Strong El Ninos, on average, bring us above-normal temperatures and precipitation. The cold air tends to remain well to our north, so most of the precipitation falls as rain rather than snow.

Moderate El Ninos, on the other hand, seem to offer the greatest statistical chance that moisture and storms passing across the southern U.S. will "seed" the Atlantic coastal storms that tend to bring us our deepest snowfalls. We've already seen plenty of coastal storms this fall, including the big one last week that battered OC's dune line, and another one today.

Nothing is guaranteed, of course. There are other shorter- and longer-term climate patterns - Snowstorm 1996including the North Atlantic Oscillation - that can determine whether there will be, for example, enough cold air in place to make snow-makers out of the coastal storms.

That helps to explain why, of the 17 El Nino winters since 1950, eight produced above-normal snowfalls, while nine were below-normal. (Weak La Nina winters can produce big snow, too, as it did in January 1996, right, although that's less common.)

Still, there is plenty to look forward to this time, Klein said. "The above-average El Nino winters have been associated with some of our snowiest winters, especially during moderate El Nino episodes. With the ongoing El Nino episode expected to continue, even strengthen to moderate levels this winter, El Nino will likely play an important role with the winter climate here in the greater Baltimore and Washington, D.C. area."

Among the most memorable snowstorms in El Nino winters was the Feb. 11, 1983 storm that dropped 22.8 inches on Baltimore. Then there were three storms in 1987: Jan. 22 (12.3 inches), Jan. 25 (9.6 inches), and Feb. 22, (10.1 inches).

Here is another summary of the El Nino effect on Baltimore snowfall, also from the NWS at Sterling:

"El Niño winters in the Baltimore Region mean a milder than normal December. They also tend to be all or nothing when it comes to snowfall. Either there are no significant snow storms and season snow totals average less than 5 inches or there is a tendency toward multiple snow storms with seasonal totals above 30 inches.  These storms usually occur in January and February. November, December, and March often see little or no snow."

Here are still more statistics on Baltimore snow and ice.

Here are the snow totals for the past 10 years at BWI. The long-term average (1971-2000) is 18.2 inches:

2008-2009: 9.1 inches

2007-2008: 8.5 inches

2006-2007:  11.0 inches

2005-2006:  19.6 inches

2004-2005: 18.0 inches

2003-2004:  18.3 inches

2002-2003:  58.1 inches

2001-2002:  2.3 inches

2000-2001: 8.7 inches

1999-2000:  26.1 inches

Posted by Frank Roylance at 11:06 AM | | Comments (6)
Categories: Winter weather

A damp and gloomy week ahead

Another coastal storm, followed by a passing cold front and yet another coastal storm will keep our weather gray and drippy this week. The Seasonal Affective Disorder patients among us will have to hold out for sunshine on the weekend. Or fly off to sunnier climes.

On a related topic, the snow lovers along us will like the latest word from Sterling on the likelihood for some respectable snow during this upcoming El Nino winter. More on that in the next post.

For now, we're looking at rain. Or at least threatening skies, drizzle, showers and a steadier rain for at least some of us as the week goes by.

NOAAWe'll start with the next coastal storm - a harbinger, some say, of the snowy winter to come. This one is drifting up the Eastern Seaboard today, bringing Central Maryland plenty of clouds and a promise of rain later today and overnight into Tuesday.

Combined with high pressure spinning over New England, the two systems will act to funnel east winds into the region, off the Atlantic, and laden with moisture. The steadiest rain is expected to our south, in Southern Maryland, where residents can anticipate as much as a half-inch of rain.

And, while there is high pressure expected once the coastal low pulls away tomorrow, the rising barometer is not expected to be able to clear the atmosphere of the low-level moisture being pumped in today. So we'll stay cloudy on Tuesday, and may even see some patchy drizzle.

Behind that we can expect the next cold front to approach on Wednesday, bringing more clouds and increasing chances for rain. Then, by Thanksgiving Day, yet another coastal storm will be brewing, delivering more rain into the nighttime hours.

Once that low passes by, cold air will move in behind it, producing a rain/snow mix in the higher elevations of Western Maryland late on Thursday into Friday. Our highs will not top 50 degrees by Friday as colder air fills in from the northwest. But this time the rising barometer will begin the clear the skies for the weekend.  

Posted by Frank Roylance at 10:34 AM | | Comments (1)
Categories: Forecasts

November 20, 2009

Saturday is your best bet for the weekend

If you're hoping for at least one good outdoor day this weekend, it looks like Saturday will be your best bet. The next coastal storm in this autumn's continuing parade is fixing to spin on up the East Coast, and we're likely to fall under its rain shield as early as Sunday afternoon.

Saturday, however, looks great for a hike or a roll up the bike trail. High pressure centered in the Ohio Valley is building across the region today (Friday) and will bring us more sunshine Saturday, Bike trailwith a high in the upper 50s.

The relatively mild temperatures are the work of bright sunshine, and something called "downsloping." Winds out of the west or northwest flow across the Appalachians and slide down the eastern slope. And as they descend, the air is compressed, which warms it up. The average highs at BWI at this time of year are in the mid-50s.

By Sunday, however, clouds will be on the increase, with the chance of showers rising in the afternoon as a low-pressure system forming over the Gulf moves off the Southeast coast. The computer models disagree, of course, on the timing, and on how close the low will come to the shore. And, as it does with winter storms, that storm track will determine just how much precipitation we see.

Whatever we get, it's likely to arrive late Sunday into Monday. We may get a brief look at the sun again on Tuesday, but there's more rain likely at mid-week as the next cold front slides by. From this distance, Thanksgiving Day is looking like a gray one, too, with a 40 percent chance of rain.

(SUN PHOTO/Jerry Jackson/2007)

Posted by Frank Roylance at 2:01 PM | | Comments (0)
Categories: Forecasts

November 19, 2009

An account of deadly 1926 La Plata tornado

Steve Zubrick, science and operations officer at the National Weather Service in Sterling, Va., has sent me a link to an historic National Weather Service report on the Nov. 9, 1926 tornado that SUN PHOTO/Karl Merton Ferron/La Plata 2002swept across parts of Charles and Prince George's counties, leaving 16 dead (or 17, depending on your source) - including 13 school children.

The F-4 twister demolished homes and barns, carved a cross-country trail of splintered trees and carried debris as far as 50 miles before dropping it. A school teacher describes how she and her students were lifted into the air and swept away, along with parts of their demolished schoolhouse.

Sun reporter Fred Rasmussen interviewed one of the school's students, who survived because she was not in class that day; but her sister was among the dead. (No, Fred's not quite that old; the woman was in her 80s when they spoke.) Read his story, below.

Fred tracked the woman down after a similar tornado struck La Plata in April 2002. Only the third F-4 in the record books for Maryland, the 2002 tornado ravaged the town and cut a path all the way across Southern Maryland. It then spawned a waterspout on the bay, and touched down again on the Eastern Shore. Six people died. The photo above was taken four days later.  

By Frederick N. Rasmussen
   Irene B. Wood couldn't believe that it was happening again.

    A lifelong La Plata resident, Wood, 86, was watching TV in her home on Oak Avenue early Sunday evening when the sky began to grow dark.She got up from her chair to make her way to the basement after seeing a storm warning broadcast. 

    "I looked at the clock. It was six minutes after 7," she said. "I was on my way to the basement when it came, and I only got as far as the dining room. I sort of froze there." She never got downstairs. Instead, she witnessed the ferocity of the winds.

    "I kept hearing something hit the side of the house. As the widows cracked and broke, I just prayed. I lost electricity, phone, and my home was damaged," said Wood, who had been hospitalized in recent weeks for congestive heart failure. "But I thank God that I'm alive. I still get emotional when I think about it." 

    For Wood, Sunday's tornado was especially disturbing, rekindling memories of La Plata's other devastating storm -- that of Nov. 9, 1926, which killed 17, including her sister and 13 of her classmates.

    "Whenever I hear of tornado warnings in November, it comes to mind very quickly," said Wood in a telephone interview yesterday from her daughter's home in nearby Spring Hill.

    Wood was 9 years old when she attended the two-room schoolhouse on the outskirts of La Plata. She recalled that day more than 75 years ago as being unseasonably warm for November.

    "I was not in school that afternoon. I had left earlier to go to the dentist for an appointment. His office was in his home, and when we heard the wind roar, his wife took me to the window and said that the noise was that of a large airship passing overhead," she said.

    A little after 2 p.m., the savage storm raced up from the Potomac River and struck the community, creating a path of destruction 18 miles long and 140 yards wide.

    The schoolhouse that stood in its path held 56 students and two teachers. It was ripped from its foundation by the howling winds and dropped into a grove of trees about 50 feet away.

    Several children were carried 500 feet away by the swirling winds, and the naked body of a child was found in the top of a tree about 300 feet from where the school had stood.

    Beneath tons of splintered wood and debris came cries for help as residents feverishly tried to extricate those who were trapped.

    The storm zigzagged on to Prince George's and Calvert counties. A piece of the schoolhouse landed in Upper Marlboro, 25 miles away. A page ripped from a school ledger was found 36 miles away in Bowie.

    "It was horrible," said Wood. As injured children were taken to the porch of a nearby doctor where they waited for medical treatment, news came that her 7-year-old sister, Mary Ellen Bowie, was severely injured.

    "We didn't have fire or rescue squads in La Plata in those days, and someone put Mary Ellen in their car. She was so badly mangled and died on the way to Washington. It was a blessing," said Wood, who recalled that the entire town turned out for the funerals of the children.

    In Sunday's storm, Wood's brick home lost all its windows, several holes were torn in the roof and a porch column collapsed.

    "It's eerie. There is glass everywhere but not a thing out of place in the house," said Betty Carney, her daughter. She attributes the house's survival to sound construction by her father, Harry F. Wood, who built it in 1937.

    "Nothing moved or broke in the house, not one knickknack or piece of furniture moved during the storm," she said. "It's the way it's always been."    

All content herein is © 2009 The Baltimore Sun
Posted by Frank Roylance at 5:06 PM | | Comments (0)
Categories: History

November 18, 2009

More rain due; east wind brings high water

Thursday looks like a wet one as clockwise winds around a high pressure system to our northeast continues to pump an east wind and Atlantic moisture our way.

Forecasters are calling for drizzle, showers or rain late tonight, followed by a 70- to 80-percent chance for more rain on Thursday as a cold front approaches from the west. In the meantime, the Tides Onlineeast wind is shoving bay water on the western shore, with flood advisories posted for the bay south of Baltimore and for the tidal Potomac River. Feels just like last week's forecast.

Behind the cold front we'll get some clearing for nice weather Friday and Saturday. But then the next coastal storm will be firing up off the Carolinas, with another bout of rain due late Sunday into Monday.

No wintry precip expected around the northwest side of that storm, except perhaps at the very highest elevations to our west. But this pattern of repeated coastal storms bodes well for snow lovers if it keeps up through the colder months.

Posted by Frank Roylance at 6:16 PM | | Comments (0)
Categories: Forecasts

Western "fireball" may have been small asteroid


A brilliant meteor that startled residents across parts of Idaho and northern Utah early Wednesday morning may have been a small asteroid, scientists say. It exploded in the atmosphere with a force equal to a thousand tons of TNT. reports:

"Witnesses in Colorado, Utah, Idaho and elsewhere say the fireball "turned night into day" and "shook the ground" when it exploded just after midnight Mountain Standard Time. Researchers who are analyzing infrasound recordings of the blast say the fireball was not a Leonid.  It was probably a small asteroid, now scattered in fragments across the countryside.  Efforts are underway to measure the trajectory of the asteroid and guide meteorite recovery efforts."

Security camera footage of the event shows a flash that brightened the sky so much that a street light operated by a light sensor winked out for a time before the sky grew dark again.

Here's a video from local TV.

If this was a small asteroid (or a big space rock of some sort) entering the atmosphere, it would be second one in recent weeks to make news.

Posted by Frank Roylance at 5:22 PM | | Comments (3)
Categories: Sky Watching

November 17, 2009

"Vomitoxin" disaster declared in 10 Md. counties

A fungal grain infestation caused by last spring's wet weather in Maryland was bad enough to earn a federal agricultural disaster declaration for 10 Maryland counties. U.S. Agriculture Secretary Thomas J. Vilsack approved the state's request for aid in a Nov. 13 letter to Gov. Martin O'Malley.

Wheat and barley crops planted here became infected with the Vomitoxin (deoxynivalenol toxin, or DON) during May and June. The toxin is produced by a fungus called "Fusarium head blight," and the contamination makes the grain unmarketable, and unusable as feed.

Maryland barleyThe North Dakota State University describes its impact this way: "Grain with DON would have to be ingested in very high amounts to pose a health risk to humans, but it can affect flavors in foods and processing performance. Human food products are restricted to a 1-ppm level established by the FDA. This level is considered safe for human consumption. The food industry often sets standards that are more restrictive. DON causes feed refusal and poor weight gain in some livestock if fed above the advisory levels."

Maryland Agriculture Secretary Buddy Hance said, "Farmers in the disaster designation areas experienced market value losses ranging from 30 to 55 percent."

The federal disaster declaration makes farmers in the primary designation areas, and all adjoining counties, eligible for "consideration" for assistance from the USDA Farm Service Agency.

The primary counties in the disaster declaration are Baltimore, Carroll, Cecil, Harford, Howard, Kent, Montgomery, Queen Anne's, Talbot and Washington.

BWI Marshall Airport recorded more than 9 inches of surplus rain during April, May and June. Since then, more than 3.5 additional inches of surplus rain have been added.

(SUN PHOTO/Glenn Fawcett 2008)

Posted by Frank Roylance at 3:18 PM | | Comments (0)
Categories: Phenomena

Tom Turkey on the road to ... dinner

 Tom, on the road

I was driving to work on I-83 Monday when I pulled alongside this flatbed truck from Locust Point Farm in Elkton, loaded with cages holding dozens of turkeys. It wasn't hard to imagine where they were headed.  Fortunately for these guys, we celebrated early. All turkeyed out. 

Speaking of seasonal critters, anyone else under siege by box elder bugs and ladybugs? They all want to come indoors. Crickets, too.

Posted by Frank Roylance at 2:50 PM | | Comments (4)
Categories: Cool pictures

Last week's rain totals mapped

AP Photo/Jason HirschfeldThe National Weather Service has produced a map of the 72-hour rain totals during last week's nor'easter.

The map makes clear just how much more seriously affected counties to our south were, and especially those in southeast Virginia (left). Rain totals there ran above 10 inches in some places.

Out in far-western Maryland, meanwhile, there was little or no rain from the coastal storm.

(AP Photo/Jason Hirschfeld in Hampton Roads. Va. Nov. 13, 2009)


Posted by Frank Roylance at 2:39 PM | | Comments (0)
Categories: By the numbers

Antarctic ozone hole shrinks, a little


The ozone "hole" over Antartica reached its southern springtime peak in September, according to researchers with the National Oceanic and Atmospheric Administration. Measurements there indicated the size of the gap in the layer of the planet's atmosphere that protects us from dangerous ultraviolet radiation was the 10th largest on record.

That sounds bad, but the data suggest that the hole has actually begun to shrink thanks to international restrictions in the early 1990s on the production and sale of products containing chlorofluorocarbons (CFCs), mostly as propellants and refrigerants. The chemicals were discovered to be responsible for high-altitude chemical reactions in the coldest places on Earth that were destroying ozone molecules. Man-made ozone is a pollutant at ground level, but naturally occurring ozone high in the atmosphere acts as a shield against harmful solar radiation. NOAA

The other piece of the measurement is the amount of ozone in a vertical column of air over South Pole Station. That's measured in something called Dobson Units.

The least amount of protective ozone ever measured there was 89 Dobson Units, in 1993. This September, the lowest reading was 98 Dobson Units. That's the seventh lowest on record, but an improvement.

The chart at right shows the average Dobson readings for the last half of October each year. You can see that the depletion appears to have ended during the 1990s, and ozone readings have stabilized and perhaps ticked up a notch.

But the progress is painfully slow. At this rate, the ozone hole won't return to normal until the 2060s. By then, lots of us (including me) will be dead. But our children and grandchildren will be around, and I hope they throw a big party and thank their ancestors for thinking for the long-term (for a change).

You can read more about this year's measurements here.

Posted by Frank Roylance at 11:02 AM | | Comments (0)
Categories: Phenomena

November 16, 2009

Forecast hopeful for Leonid meteor shower tonight

With the moon entering its "new" phase tonight, the skies should be ideally dark for viewing Tuesday morning's peak of the annual Leonid meteor shower. And the weather forecast, while not ideal, calls for partly to mostly clear skies. With cooler air moving in with a high-pressure system out of the Great Lakes, our skies should be drying out from this morning's foggy humidity. That will help clear the atmosphere for the best view of the "shooting stars." 

The Leonids occur each November when the Earth, in its annual orbit around the sun, passes through remnants of the dust trails left behind by the passage of Comet Tempel-Tuttle, which passes through this area of the solar system every 33 years. Astronomers say the trails we'll be intersecting tonight were laid down by the comet in AD 1466 and 1533.

Here's more from Sky & Telescope.

Leonid meteor/Mike HankeyUPDATE: Here (left) is a meteor captured by amateur astrophotographer Mike Hankey, in northern Baltimore County, during the Leonid shower. It may be a "sporadic," rather than a Leonid. Still a nice shot, better than anything I've ever managed. Mike said:

"At the time I was focused on Procyon and shooting continuously and waiting and watching. I saw a meteor radiate directly out of [the bright star] Procyon and was like, NO WAY! But I check the camera screen and couldn't see anything. I didn't realize I caught it until this morning when I was reviewing the pics.

"It was much brighter in person, it's a little faint in the pic. Still really happy I caught it."

Here's Mike's Web site.

Earlier post resumes here:

Some Leonid showers have reached "storm" proportions, with counts of more than 1,000 per hour in some locations. This year's show, for eastern North America, is expected to produce rates of a more conventional 20-30 per hour. But any time you can spend an hour under the night sky and see 20 meteors, some with persistent trails, is a memorable night out.  

The best time to look will be in the hours before dawn - say, 3 or 4 a.m. until the dawn begins to brighten the sky.

Intrepid meteor watchers should find the darkest location they can, as far from urban light pollution as possible. Look for a place with a broad view of the sky. The shower's "radiant" is the constellation Leo - the place in the sky from which the meteors seem to emerge as the Earth plows into them. 

Leo rises in the northeast after 11 p.m. By 4 a.m. it will be high overhead, and the meteors will appear to be flying away from it in all directions. So you can look anywhere for them.

When it's over, as always, come back here, leave a comment and let everyone share the experience. Good luck!

Posted by Frank Roylance at 2:52 PM | | Comments (6)
Categories: Sky Watching

November 13, 2009

24-hour rain totals top 5 inches in St. Mary's Co.

While Baltimoreans may simply be tired of the gray, and the gloom, and the drip, residents of Maryland's southern counties - on both sides of the Chesapeake, are dealing with a serious deluge of rain and high tides from the big coastal storm that remains almost stationary off the NOAACarolina coast, driving wind, rain and water inland.

Here's an animation of the storm's water vapor movement, from satellite sensors.

Precipitation totals in St. Mary's County for the past 24 hours have topped 5 inches, with some locations reporting nealy six inches and one - Great Mills - exceeding 7 inches. Normal rainfall for the month of November at BWI is 3.12 inches.

Here is a rain total map for the storm

High water and fallen trees have forced a number of road closings in the Leonardtown area, and delayed delayed school for some students Thursday as buses were re-routed around flooded roadways.

Ocean City has received 3.69 inches of rain since the storm arrived, the heaviest falling early Thursday evening. That's the Rehoboth Beach Web cam below.

Coastal Flood Warnings remain in effect Friday morning for Charles, Calvert and St. Mary's counties. Tides were expected to run 2.5 to 3 feet above normal  into Saturday before the storm begins to drift away from the mainland. Colton's Point and St. George's Island in St. Mary's County, and Solomons Island in Calvert were warned to expect significant flooding.

In addition, Ocean City was under Wind Advisories until 7 p.m. Friday. An earlier hHigh Wind Warning was cancelled. Winds are now forecast to Rehoboth Beach camaverage 25 to 35 mph, with gusts to 50 mph before weakening late in the day. With the soil saturated, such winds can be expected to topple some trees, causing more power outages. The Atlantic coast is also under a High Surf Advisory until 6 p.m. Friday. Tides at the Inlet are expected to exceed predictions by more than 5 feet, with moderate flooding in Ocean City.

Coastal Flood Advisories were up for Anne Arundel and Prince George's counties. Gale warnings and small craft advisories were posted for the Chesapeake. 

The rain amounts decrease as you travel north almong the Western Shore. Prince Frederick, In Calvert County, recorded 4.18 inches by Friday morning. Baltimore-Washington International Thurgood Marshall Airport reported 1.24 inches. The storm has left just under an inch here at The Baltimore Sun in downtown Baltimore.

Here is a list of rain reports, as of Friday morning, from the National Weather Service.

As thick and damp and gloomy as it is here, it's interesting to note that clear, dry, sunny weather lies barely 150 miles to our west, beyond the reach of this slow-moving nor'easter.

Oakland, in Garrett County, is reporting "a few clouds" this morning. Elkins, W.Va. is sunny. So are Pittsburgh, Pa., and State College, Pa.  

Posted by Frank Roylance at 10:35 AM | | Comments (1)
Categories: By the numbers

November 12, 2009

Storm sits and spins; we get wet


That storm off the Carolinas continues to churn on Thursday, stoked by energy and Gulf moisture from the remnants of Tropical Storm Ida. Coupled with the high over New England, the two weather engines are sending northeast and east winds onshore, bringing us a steady drip of rain, and driving tides high onto the east-facing shores of the Atlantic and up the Chesapeake.

Here's the view from orbit. Here's Weather Underground blogger Jeff Masters, calling the storm surge at Norfolk "historic." And here is more on the storm from NASA.

The National Weather Service has issued a slew of watches and warnings today as tides swell toward minor-to-moderate flood levels. High winds and heavy rain mostly south and east of Baltimore and Washington are adding to the local problems, which have already resulted in some road closures in Southern Maryland. More are expected.

Leonardtown and Hollywood, both in St. Mary's County, have already reported more than 2 inches of rain from the storm.   Ocean City, too, was getting hammered by rain, wind and high water.

The forecast for BWI coming out of Sterling calls for a pretty steady rain Thursday and Friday, with rain chances only slightly reduced for Friday, but diminishing overnight and into Saturday morning. The drying out should begin later on Saturday, with sunshine on tap for Sunday and the early part of next week. In all, Baltimore could see as much as an inch of additional rain, on top of the inch or so we've already recorded. If this were January we'd be out shoveling.

Among the many watches and warnings out this morning: NOAA/Tides Online

The NWS has issued coastal flood advisories for the Western Shore of the Chesapeake, where tides were running a foot above predicted levels Thursday morning at Annapolis (right), with higher levels expected at high tides times on Friday.

Flood watches and warnings are up for Friday from Anne Arundel County south to St. Mary's. Md. 244 near Redgate and Old Rolling Road in Great Mills were flooded in spots this morning as heavy rains drove streams over their banks, county authorities there reported.

Gale Warnings (winds 34 to 47 knots) are up for the northern portion of the Chesapeake, including Baltimore Harbor, with Storm Warnings (winds 48 to 63 knots) until 6 Thursday evening for the southern portion.

A High Surf Advisory is up for the ocean beaches, with rip currents and local beach erosion expected. Here are some OC Web cam views of the surf

Posted by Frank Roylance at 10:18 AM | | Comments (5)
Categories: Forecasts

November 11, 2009

Developing coastal low deals us rain into weekend

Persistent northeast winds, energized by a slow-moving coastal storm intensifying off the Carolinas, and high pressure over New England, will keep Maryland in a northeasterly flow off the Altantic for the rest of the week. And that will mean a series of cool, gray, drippy days, with gusty winds and increasingly high tides.Calvert Street ginkgos So much for what had been a sunny forecast for the end of the week.

Some of this mess can be linked to the remnants of Tropical Storm Ida, including much of the rain that has moved into the region overnight and the energy that is fueling the coastal storm.

The counter-clockwise flow around the coastal low is combining with the clockwise flow around the New England high-pressure center. And that is funneling northeast winds into the region. 

The storm is shoving Gulf and Atlantic moisture northward into the region, where it is running up against the cold front and clear, dry air, that lies to our north and west. And that flow is what's delivering our drizzle and rain today.  (Those are The Sun's ginkgo trees, on Calvert Street, at right. The photo doesn't do them justice.)

The heaviest rain is expected to remain south and east of the Baltimore-Washington area. So will the gale-force winds forecast for the central and southern portions of the Chesapeake. Along the coast, winds will reach 15 to 20 mph in the next day or two, with gusts to 25 or 30 mph.

Town of Ocean CityAll that wind, coupled with an approaching new moon, will drive more water onto the beaches, and hold it against the Chesapeake shoreline. Coastal Flood Watches have been posted for Friday on the Chesapeake Bay and the tidal Potomac River. Minor to moderate flooding is possible at periods of high tide Friday afternoon and Saturday.

A Gale Warning is up for Thursday on the lower tidal Potomac and the Bay south of Sandy Point.

Out on the ocean beaches, there is heavy rain in the forecast. (Ocean City's beaches, left, were deserted this morning.) 

The National Weather Service's Wakefield, Va. forecast office has posted High Wind Warnings from Maryland to the Outer Banks, effective from 6 p.m. Wednesday evening until 11 a.m. Friday morning. Winds will average 30 to 40 mph with higher gusts.

High Surf Advisories Coastal Flood Warnings are also up for the Delmarva beaches, with tides two to four feet above predicted levels.  

Posted by Frank Roylance at 10:20 AM | | Comments (1)
Categories: Forecasts

November 10, 2009

October was wettest, third-coolest on record for U.S.

NOAANOAA's October data are in, and the agency is rpeorting the October in the U.S. was, on average, the wettest, and the third-coolest October on the 115-year record for the lower-48 states.

Temperatures were below-normal in all regions except the Southeast (and in New Jersey, Delaware and Maryland, which were near-normal). Florida was the only state to report above-average temperatures. (Left)

The cross-country average of 4.15 inches of rain was the highest on record, nearly doubling the long-term average for October. Moderate-to-exceptional drought covered 12 percent of the contiguous United States, the second-smallest drought footprint of the decade, based on the U.S. Drought Monitor.

You can read the entire release, here. (Cue the global warming skeptics...)

On the other hands, atmospheric scientists say the proportion of record high temperatures to record lows across the U.S., is going up.

Posted by Frank Roylance at 4:02 PM | | Comments (0)
Categories: By the numbers

Ida's remnant rain may stay mostly south of us

Forecasters at the National Weather Service's Sterling forecast office are wrestling with computer models that can't quite agree on how much of Ida's moisture will make it to Maryland this week.

Remnants of what was once the third hurricane of the 2009 season have crossed the Gulf Coast and swept inland, bringing heavy rains to parts of the Deep South. But there is high pressure to NOAAour northwest, and a cold front ahead of it that appears to constitute a barrier to the northward advance of Ida's rains.

"It's the remnants of Ida, and how quickly/how far its rainfall spreads northward that will determine the outcome of this forecast," the forecasters say in this morning's discussion.

For now, the official forecast out of Sterling is calling for a chance for rain to develop after 10 p.m. this evening as the Gulf moisture begins to run up against the cold front. Veterans Day comes with a 30 percent chance for rain or drizzle, with temperatures held in the mid-50s. The drizzle chances continue in to the evening. But the rest of the week, and right into early next week, looks sunny with seasonable highs near 60 degrees.

Whatever happens here, it appears the coastal counties will see some considerable wind and rain in the next few days, with some chance for minor coastal flooding as a series of offshore lows keep persistent northeast winds shove more water onto the bay and ocean shorelines.

Posted by Frank Roylance at 11:32 AM | | Comments (2)
Categories: Forecasts

Reader recalls early 1953 snowstorm

Last week I wrote a brief comment on the print weather page about the early snowstorm that paralyzed Baltimore back on Nov. 6-7, 1953. I wondered if anyone would remember the storm, which was the earliest "heavy" (four inches or more) snowfall in Baltimore weather records.

This week I received the following note from Joan Parr, who clearly did. She writes:

1953 SNOWSTORM"Mr. Roylance:

"If my memory serves me right, the storm you mentioned in your blog (on Friday, Nov. 6. 2009)  was indeed a traffic-snarler.  Drivers acted as if they had never seen snow before, and they just kept moving, right into intersections, creating gridlock. 

"This storm was, I believe, the impetus for Baltimore City to lure Henry Barnes away from Denver to come and make sense of our streets and traffic lights.  He did a very good job; one of his legacies which still exist in Baltimore is the "Barnes Dance,"  where all vehicular traffic is stopped and pedestrians are free to walk across the streets unobstructed by cars and trucks.

"Thank you for the reminder of that storm.    Joan K. Parr "   

(SUN PHOTO/Nov. 6, 1953/Cecil County)

Posted by Frank Roylance at 10:43 AM | | Comments (0)
Categories: Winter weather

November 9, 2009

Unhealthy air quality in Baltimore

Air Now  

The Maryland Department of the Environment is forecasting unhealthy air quality for "sensitive groups" in Baltimore again on Tuesday, for the second day in a row. Sensitive groups include children and people with heart and respiratory ailments. They should limit their time outdoors. Healthy adults are unlikely to be affected.

Until this week there had been only four "Code Orange" days this year when particulate readings have reached unhealthy levels in the Baltimore region, with none since March, according to the MDE. (That's the Key Bridge through this morning's haze, above.)

High pressure over the region, combined with stagnant air, may be contributing to the unhealthy levels of particulates (soot), weather forecasters said. Air quality in Baltimore also reached unhealthy levels for particulate matter on Monday. Cecil County, too, is under an air quality alert from 1 a.m. Tuesday until 1 a.m. Wednesday. 

Here's more from the Clean Air Partners Website:

"Unlike ground level ozone, particles are not a seasonal pollutant; high levels can occur any time of the year. Unhealthy levels of particle pollution in the air can cause or trigger significant health problems. These range from coughing and difficult or painful breathing to the possibility of an emergency room visit or even premature death. Exposure to particles can decrease lung function, weaken the heart, and possibly bring on a heart attack. The environment also suffers from particle pollution. Particles are the major source of haze, and can harm the environment by changing the nutrient and chemical balance in soil and water."

Better days are coming soon.

"It shouldn't be long-lived," said National Weather Service forecaster Andy Woodcock said of the air pollution. After Tuesday, "the wind will go to the north northeast and stay there for a while." And that should clear the air.

Posted by Frank Roylance at 5:15 PM | | Comments (0)
Categories: Air quality

NASA posts very cool movie of Tropical Storm Ida

NASA GOESThe NASA Goddard Space Flight Center has assembled a very nifty movie from GOES satellite images of former Hurricane Ida, beginning as the storm entered the Yucatan Channel Nov. 7 and began to threaten the U.S. Gulf Coast, where it is making landfall today.

Have a look here.

From the clip, it becomes clear that the clouds that have overspread our region today formed from Gulf moisture and convection just west of Ida. But that flow of moisture from the western Gulf has now merged with Ida's, and the result is mild, cloudy weather for Maryland.

Posted by Frank Roylance at 3:00 PM | | Comments (0)
Categories: Cool pictures

Ida limps toward land; could become nor'easter

An increasingly disorganized Ida weakened to tropical storm force overnight, but continues to pose a significant threat to the Gulf Coast and inland regions of the Southeastern U.S.

After landfall, the storm could reform off Cape Hatteras as an Atlantic coastal storm, bringing rain, wind, heavy surf, beach erosion and coastal flooding to shore communities from the NOAACarolinas to New Jersey, forecasters say.

The biggest immediate worry is probably heavy rain and flooding in an area of the Deep South that has already seen more than enough rain this fall.

As Ida's center moves toward land Monday, wind shear is sending the heavy precipitation onshore well ahead of the surface low. Rainfall along the Gulf Coast today will likely total 3 to 6 inches, with some locations receiving as much as 8, forecasters said.

Once the storm's center finally reaches shore, high winds will bring water levels 3 to 5 feet above normal along the Gulf near and to the east of landfall, all compounded by large and destructive waves. 

Winds, meanwhile, have diminished. The storm's top sustained winds were "just" 70 mph at last check. All hurricane watches and warnings have been dropped. Tropical Storm Warnings remain in place from Grande Isle, La. to the Aucilla River, Fla. New Orleans and Lake Ponchartrain are included in the warning area.

Here is the latest advisory for Ida. Here is the forecast discussion. Here is the forecast storm track. And here is the view from space. Ida may already have played a role in the heavy rains and mudslides that killed more than 120 people in El Salvador over the weekend.'s Alex Sosnowski, meanwhile, is looking ahead a few days. He says Ida's energy could reorganize off the Atlantic coast after mid-week, taking on the proportions of a strong nor'easter. That would mean gusty onshore winds, large swells, rough surf and coastal flooding for interests from Hatteras to the Jersey Shore, including Maryland and Delaware beaches.

"The angry sea will lead to strong and frequent rip currents," Sosnowski said. "Bathers are advised to avoid the water from Wednesday into the weekend." Likewise, small craft operators should stay in port from Florida to Long Island, at least until Friday.

Baltimore's forecast calls for a chance of showers Tuesday through Thursday.

As they depart, Ida's remnants are expected to draw cold air into the region, dropping daytime highs from the low 70s, which are expected to go today, to the 50s by the latter half of the week. "The threat of heavy snow with this event has diminished," he adds, "since the storm will quickly migrate to the coast."

Mr. Foot, take note.

Posted by Frank Roylance at 10:12 AM | | Comments (1)
Categories: Hurricanes

November 8, 2009

Hurricane Ida steams into Gulf; watches up for La.


Just when you thought we'd slipped by without a late-season hurricane this fall, Hurricane Ida puffs up and appears to be headed for the northern Gulf Coast.

The National Hurricane Center has posted Hurricane Watches from Grand Isle, La. to the Alabama, Mississippi state line. There are flood warnings up for New Orleans, which is expected to get heavy rain. The Hurricane Watches mean hurricane conditions could develop within 36 hours, although forecasters do expect the storm will begin to lose its tropical characteristics Tuesday as it nears the Gulf Coast and experiences wind shear and cooler waters. Some chance remains, however, that it could still be a tropical storm at that point.

The storm at last check was about 75 miles northeast of Cozumel, Mexico, and about the same distance southwest of the western tip of Cuba. The storm is moving through the Yucatan Channel, and into the Gulf of Mexico.

Top sustained winds are estimated at near 90 mph, making Ida a Cat. 1 storm.

UPDATE: Ida has strengthened today to a Cat. 2 storm, with top sustained winds of almost 100 mph. The watches have been extended farther east along the Gulf Coast. The National Hurricane Center's advisory includes the following:


Here is the latest advisory. Here is the forecast storm track. And here is the view from space.

Posted by Frank Roylance at 11:28 AM | | Comments (0)
Categories: Hurricanes

Mr. Foot sees "smackdown" storm coming

I missed this when it appeared last week. Some kind of problem with my "Favorites" list. Anyway, Mr. Foot, a Baltimore County science teacher and Maryland weather watcher much-consulted by county teachers and students eager for a snow break in winter time, is forecasting a "smackdown" storm here by mid-month.

Says he: David Hobby/Sun Photo

"I've maintained a position that the atmosphere is primed and ready to deliver, all we wait for now is "Only Time." I realize we haven't dug out the Thanksgiving decorations yet, but I can't resist the urge to tell you that before long, we will be reveling in the sight of "White in the Winter Night."

Here's the sequence for his early-season prognostications:

11/01-09: A mild to cool period then brief warmup

 * 11/10-15: Possible outbreak of Arctic air on or before 11/15

 * In same week, a "smackdown" storm with snow at the onset

 * 11/15-25: "yo-yo" period of below then above-normal temps

 * 11/25-12/5: Seasonal temps leading to kickoff event by 12/5.

To read the rest of his forecast, visit his blog, here.

(SUN PHOTO/David Hobby/McHenry, Md., October 2006)

Posted by Frank Roylance at 7:23 AM | | Comments (3)
Categories: Winter weather

November 7, 2009

Heads up! Space Station flyby Sunday evening

The International Space Station is back in our evening skies, and on Sunday evening the big contraption will be flying up the East Coast and almost directly over Baltimore. (And even more directly over Ocean City.) 

The weather forecast is quite promising for this pass, and the station will appear especially bright, even in badly light-polluted urban settings. It's also a convenient early-evening pass, so sky watchers will have no excuse not to step outside with the kids and get a look at your (and their) tax dollars at play.

The only hitch is that on this pass the ISS will fly into the Earth's shadow and disappear well before reaching the northeast horizon, cutting short our view, which of course depends entirely on sunlight reflecting off the hardware.

Watch for the station as it rises above the southwest horizon at 6:14 p.m. It will appear like a bright star, hustling across the sky. If you see blinking strobes, multiple or colored lights, that's a airplane. Keep looking.

NASA ISSThe ISS will pass well above the planet Jupiter, which is now the brightest object in the southern sky. It will reach a maximum elevation of 70 degrees above the southeastern horizon at 6:17 p.m., and soon after that fade quickly away as it enters the Earth's shadow - another brief nighttime for crew aboard the station.

There are currently six crew members aboard the ISS. They include two Americans (one male, one female); two Russians; one Belgian (the first European expedition commander) and one Canadian, all male.

They are currently preparing for the scheduled arrival of the Space Shuttle Atlantis on Nov. 16. The flight, to deliver spare parts to the station, is one of the last six shuttle flights on the NASA manifest before the fleet is retired in 2010. After that, under current plans, the U.S. will have to rely on Russian vehicles to support the station and its crew. 

Note to Bucket Listers: If you have never seen a shuttle launch in person, start planning now to get down to Florida to watch one of these spectacular events before it's too late. TV images of a shuttle launch do not do the experience justice. You can't see that blinding flame, hear the crackling engines, or feel the sound in your chest.

And, with the cameras focused on the shuttle, you lose all sense of the space ship's acceleration and speed as it leaps into the air and disappears from view. You simply can't believe that people willingly ride that monster. Be there.

Posted by Frank Roylance at 7:00 AM | | Comments (3)
Categories: Sky Watching

November 6, 2009

Ida headed for Gulf this weekend

Weakened to tropical depression status and somewhat disrupted by its passage over parts of eastern Nicaragua and Honduras, Ida is continuing to drop life-threatening rain over the Central American countries. But the storm is expected to move back over water late today, into the NASA GOESnorthwest Caribbean, and on toward the Gulf of Mexico over the weekend.

Forecasters at the National Hurricane Center are getting conflicting predictions from their computer models and other guides. But the guesswork seems to be settling on a storm track into the central Gulf by early next week, with a likely curve toward Florida.

Although there is at least one model forecasting the storm will regain hurricane force, the NHC seems to be holding Ida's redevelopment to tropical storm force for the moment, citing continuing wind shear in the region and cooler waters in the Gulf.

Here is the latest advisory. Here is the forecast discussion. Here is the forecast storm track, and here is the view from orbit.

Posted by Frank Roylance at 12:20 PM | | Comments (0)
Categories: Hurricanes

Freeze warning tonight; tender plants doomed

Temperatures along the I-95 corridor are set to drop into the upper 20s and low 30s Friday night into Saturday morning. The National Weather Service has posted freeze warnings from 1 a.m. to 8 a.m. Saturday for Baltimore, Washington and all counties along the Chesapeake from Harford in the north to St. Mary's in the south.

The hard freeze will finally bring the 2009 growing season to a halt in the area, and kill off any Calvert Street ginkgostender plants that are still outdoors tonight.

The forecast low for BWI-Marshall Airport - and for much of the surrounding region tonight, is 29 degrees, which would be the lowest reading there since April 13, when the low was also 29. Downtown, the low is likely to be slightly higher, around 33 degrees.

The cold night is brought to us courtesy of high pressure that's been building in from the Ohio Valley. That's bringing clear skies and, as it moves closer tonight, calming winds. And that is the recipe for radiational cooling tonight, which will bleed away much of the solar heating we're able to store up today, and drop temperatures.

The weekend and the early part of next week look like they'll remain mostly sunny during the day, and clear at night. Daytime highs should poke back into the 60s by Sunday.

Then there's this from the NWS:

ANY REMNANTS OF [tropical storm] IDA WELL SOUTH OF THE CWFA [forecast area] NEXT WEEK."

(SUN PHOTO/Algerina Perna/Calvert Street ginkgo tree 11/9/2008)
Posted by Frank Roylance at 10:18 AM | | Comments (1)
Categories: Forecasts

November 5, 2009

See the universe ... from Dundalk

The forecast is promising for Friday evening, a good opportunity to see the stars from the Comunity College of Baltimore County's Dundalk campus.

The Department of Astronomy in the School of Mathematics and Science will have its big Celestron 14-inch CGE 1400 XLT (sounds impressive, doesn't it?) telescope set up to provide the public withNASA a close-up view of the heavens. One prominent target, I expect, will be the planet Jupiter, which is shining brightly high in the southern sky this month. Here it is in this NASA photo, with four of its moons.

This will be the first in a series of Friday evening observing sessions for the public in Dundalk this fall. Here's when and where and how:

Nov. 6, 7-9 p.m.

Nov. 20, 7-9 p.m.

Dec. 11, 7-9 p.m.

If the skies look iffy, give them a call, 45 minutes before the start of the session, at 410 282-3092 to see if it's still on.

Address: 7200 Sollers Point Road, Dundalk. Turn into CCBC Dundalk from Sollers Point Road and take the first right into the parking lot. Walk to the observatory.

Posted by Frank Roylance at 12:48 PM | | Comments (0)
Categories: Sky Watching

Ida is now a hurricane

Tropical Storm Ida became the season's third hurricane overnight, with top sustained winds of 75 mph. The storm moved onshore on the Caribbean coast of Nicaragua, some 60 miles north of the NOAAtown of Bluefields, and was expected to weaken over land. But forecasters are still predicting Ida will move back over water into the northwest Caribbean and restrengthen.

UPDATE: 1 p.m. EST. Ida was downgraded today to a tropical storm.

The storm is producing heavy rains, with 5 to 7 inches likely in most locations, and as much as 20 to 25 inches possible in some spots. Those conditions would produce life-threatening flooding and mudslides.

While there remained some possibility the storm will dissipate while over land, the forecast storm track still has Ida moving into the Gulf of Mexico by Tuesday, at tropical storm strength, posing some risk for the Gulf Coast of the U.S. 

Here is the latest advisory for Ida. Here is the forecast storm track. And here is the view from space. 

Posted by Frank Roylance at 10:34 AM | | Comments (1)
Categories: Hurricanes

November 4, 2009

New tropical depression forms as season fades

The National Hurricane Center is tracking the 11th tropical depression to form this season in the Atlantic basin. The 2009 hurricane season officially ends at the end of this month.

The new storm, designated Tropical Depression 11, got its act together Tuesday in the southwestern Caribbean, and now threatens the Nicaraguan coast and offshore islands with torrential NOAArains and 35-mph winds. It may well become the season's ninth tropical storm - Ida - later today.

UPDATE: 4 p.m. TD 11 became Tropical Storm Ida this afternoon. Top sustained winds are at 60-mph, with higher gusts. Some further intensification is likely before landfall in Nicaragua. Rainfall as high as 20 or 25 inches are possible in some locations, raising the danger of flooding and mudslides.

Forecasters think the storm will weaken as it goes ashore, and crosses over portions of Nicaragua and Honduras. But it is expected to head north, move back over the northwest Caribbean and regain tropical storm strength as it heads into the Gulf of Mexico next week. One computer model even has it reaching hurricane strength.

TD 11 was located this morning about 125 miles east southeast of Bluefields, a former buccaneer hideout on the Caribbean coast of Nicaragua. It was moving toward the northwest at about 8 mph.

Here is the latest advisory on TD 11. Here is the forecast storm track. And here is the view from orbit.  

Posted by Frank Roylance at 10:48 AM | | Comments (0)
Categories: Hurricanes

November 3, 2009

"Killing frost" possible tonight west of I-95

Clear skies and calming winds could combine to produce a hard freeze tonight in portions of the state west of the urban corridor. The National Weather Service forecast office in Sterling, Va. hasn't posted any frost or freeze warnings yet (except in Cecil County and on the upper Eastern Shore), but there is a "Hazardous Weather Outlook" noting that:


UPDATE: The NWS this afternoon issued a frost advisory for all counties north and west of Baltimore, including northern Baltimore, Carroll, Howard, Frederick, Montgomery and Washington counties:




The forecast low for BWI tonight is 37 degrees, but that drops off quickly to 33 degrees in NWSWestminster, 32 in Shrewsbury, Pa., and in Poolesville, Md.

Thursday night may be even colder, with a low of 35 at BWI, and below freezing well west of the city. There are snow showers in the forecast for Garrett County late Wednesday and Thursday.  

NOTE TO READERS: The barrel's empty. Be famous for a day. Send in your weather or backyard astronomy questions and see them answered on the Page 2 print weather page. Or is it Page 3 now?  Thanks! - FDR 

Posted by Frank Roylance at 11:42 AM | | Comments (0)
Categories: Forecasts

Leonid meteors are up next

Astronomers are predicting an exceptional year for the annual Leonid meteor shower, which will peak two weeks from today. The Leonids are among the best meteor displays on the astronomical calendar. November nights (with luck) can be clear and crisp, and this shower has occasionally ramped up to very high - even storm - rates.

This year's viewing, assuming the weather cooperates, will be enhanced by the total absence of moonlight; the moon will be "new" that night.

But the best hope for sky watchers is that the people who have learned to forecast these things seem to be in broad agreement that the Earth this year will be passing through the core of some heavy streams of dust left behind by the comet Tempel-Tuttle in past centuries.

Leonid meteors 1998If they're right, observers in central and eastern Asia will have the best view, with meteor rates forecast to exceed several hundred per hour as we slip through the dust left by the comet during its passes through the inner solar system in the years 1466 and 1533.

That will occur 12 to 14 hours after the best viewing time for those of us stuck here in eastern North America, according to an article on

Here, in the hours between 3:30 and 5:30 a.m. Nov. 17, the Earth will pass through a separate stream of comet dust, spread by Tempel-Tuttle during its pass through the region in the year 1567. Forecasters anticipate "modest" meteor rates of 25 to 30 per hour. Not spectacular, but a very nice display if they're right.

And if we're clouded out, we'll get another chance early on the 18th. The Leonids are typically active a few days before and after the peak on the 17th and 18th.

The best thing about these meteors, forecasters say, is that many will leave persistent trails as they streak into the atmosphere. A couple dozen of those during a morning's watch would be something to remember.

And in the meantime, if you just can't resist getting out of bed to stand around in the cold at midnight or later, the annual Taurid shower is about to begin. It peaks between the 5th and 12th of November and, while not nearly as numerous as the Leonids, the Taurids can and do produce some spectacular fireballs. 

As with all meteor showers, you'll need clear skies and a dark location far from urban lighting. And if you're successful, be sure to come back here, drop us a comment, and let everyone know where you were, and what you saw. Clear skies! 

(AP Photo/Leonid meteors, Nov. 17, 1998)

Posted by Frank Roylance at 10:18 AM | | Comments (4)
Categories: Sky Watching

November 2, 2009

Amaze your friends with Baltimore winter trivia

1994 ice storm in BaltimoreI know it's too early in the season to be amusing readers with winter weather data. But the National Weather Service forecast office in Sterling has posted a compendium of winter weather facts for Baltimore, Washington and Dulles Airport, and it's a fun read if you're into Baltimore's annual love/hate relationship with snow, cold and ice.

For example:

1. What was the iciest winter in recent Baltimore weather history?

2. How many of the deepest snowstorms in Baltimore have occurred since your Weather Blogger moved here from Massachusetts in 1980? Is that my fault?

3. What was the snowiest month in Baltimore history?

4. How long has it been since Baltimore (BWI) experienced sub-zero temperatures? How many times have we dipped below zero since 1960?

5. How many times per winter, on average, does Baltimore get a snowfall of 4 inches or more?

For answers to these questions and more, click here. There's more here. And you can contemplate the role of El Nino in Baltimore winters, here.

(SUN PHOTO/Mark Bugnaski/Ice storm, Baltimore, January 1994)

Posted by Frank Roylance at 5:43 PM | | Comments (0)
Categories: Winter weather

October ends wet; November brings snow risk

The data are in, and no matter how wet and cool you remember October 2009, while it did end very wet, the temperatures averaged out to an almost precisely normal 55.3 degrees for Baltimore.

BWI temperatures Oct. 2009Rainfall for the month totaled 6.24 inches. That's a surplus of more than 3 inches, and the wettest October since 2005, when Tropical Storm Tammy's remnants drove the total to 9.23 inches.

And if you still feel like it was a cold October in Baltimore, it's probably the first half of the month that's stuck in your weather memory. Fourteen of the first 20 days of the month averaged cooler than the norm. 

The month's low was 34 degrees, on the 20th. The high was 83, on the 9th.

The coldest spell was from Oct. 14 through the 20th, a seemingly endless string of chilly, rainy days with temperatures averaging close to 10 degrees below the seasonal norms. Daytime highs stalled in the 40s to 50 degrees for four days straight. More than 3 inches of rain fell at BWI-NOAA BWI rainfall Oct. 2009Marshall in those same four days.

But we also enjoyed 12 October days of 70-plus temperatures, including one day in the 80s. Seventeen days were rated clear or partly cloudy.

And now November...

Average high temperatures for Baltimore in November slide from 61 degrees on the 1st to 51 degrees on the 30th. The average lows dip from 38 degrees to 31 degrees. The records run from 86 degrees (on the 1st in 1950), to 12 degrees (on the 30th in 1929).

Snow becomes a serious possibility in November for the first time. Many Baltimoreans will NOAA BWO November tempsremember the Veteran's Day storm on Nov. 11, 1987, which left an official 6 inches at BWI, but caused much more disruption than the number would suggest.

The deepest November snowfall on record for the city is 8.4 inches, which fell on Nov. 30, 1967. Measurable snow has fallen here on all but eight dates in November.

The oldest weather record still standing for Baltimore in November seems to be the 1.79 inches of rain that fell on Nov. 23, 1879, still the record for that date. Also notable is the cold stretch from Nov. 19-24, 1880, when the maximum daily temperatures stalled near 30 degrees. Four of those high readings are still record low maximums for the dates.  

Posted by Frank Roylance at 11:13 AM | | Comments (0)
Categories: By the numbers

Sun struggles through cloud deck

Sunshine and clear skies continue to grace Maryland counties to the west of the I-95 corridor. But somehow the clouds have lingered stubbornly over the urban corridor, despite all that hope we lavished on the situation Sunday.

NOAAForecasters out at Sterling say the problem has been the slow-moving low off the Carolinas, which has kept the clouds clinging to the coastline. The problem now becomes whether that coastal storm will drift azway, and clear our skies, before the next weather disturbance moves in with a weak cold fron on Tuesday.

"Did an update to try to better depict the cloudy versus clear area. At the rate the cloud cover seems to be waning, another may be needed shortly to paint a more optimistic picture," the weather folks said in their Monday morning discussion.

The good news is that none of the forecasts include more rain for our area, although some places in the mountains could see some showers Tuesday morning, and maybe some snow showers by Thursday morning as temperatures there sink into the 20s. Our week looks generally sunny after today, with highs at BWI in the 50s to near 60 degrees.

The weather news headline for us - aside from those promises of sunshine - may be the Tuesday-into-Wednesday-morning forecast for lows near the freezing mark. That would be the coldest reading of the season so far, and could put an end to the growing season for the northern and western Baltimore suburbs. The city low forecast for Wednesday morning is around 40 degrees.

Finally, the full Hunter's Moon (or, if you prefer, the Frosty Moon or the Beaver Moon) rises over Baltimore tonight beginning at 4:41 p.m. EST. With any luck, the clouds will be gone.

Posted by Frank Roylance at 10:49 AM | | Comments (0)
Categories: Forecasts

November 1, 2009

Here comes the sun

NOAADon't despair, Baltimore. The weather gods have been taking their time, but the cold front is moving off, and the cloud deck over our heads is about to pass off to the south and east of the city.

So the sun should be coming out shortly. Here (left) is the satellite view of the region, taken around noon Sunday.

You can see the clear skies out to our west. And here's the Northeast radar loop.

Forecasters say the week ahead looks cool, but sunny

Hagerstown is already under fair skies.

Hang in there.

Posted by Frank Roylance at 12:56 PM | | Comments (0)
Categories: Forecasts
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About Frank Roylance
This site is the Maryland Weather archive. The current Maryland Weather blog can be found here.
Frank Roylance is a reporter for The Baltimore Sun. He came to Baltimore from New Bedford, Mass. in 1980 to join the old Evening Sun. He moved to the morning Sun when the papers merged in 1992, and has spent most of his time since covering science, including astronomy and the weather. One of The Baltimore Sun's first online Web logs, the Weather Blog debuted in October 2004. In June 2006 Frank also began writing comments on local weather and stargazing for The Baltimore Sun's print Weather Page. Frank also answers readers’ weather queries for the newspaper and the blog. Frank Roylance retired in October 2011. Maryland Weather is now being updated by members of The Baltimore Sun staff

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