You could almost call it a "cool wave." But "cool" is probably not the best word to describe the slightly-lower-than-normal highs and lows in the NWS forecast for the next seven days. A "mild wave," maybe?  Or a "pleasant wave"?

Whatever. It's welcome and it's saving us all money.

The real weather news is that we've slipped into this pattern of what meteorologists out at Sterling are calling "troughiness," as in, persistent low pressure to our north that is sweeping disturbances through the region, giving us plenty of clouds, with daily chances for scattered showers and thunderstorms.

And that seems to be keeping the temperatures in check. Highs for the next week will stall out in the low- to mid-80s. And the overnight lows will sink into the low- to mid-60s (maybe even some 50s in some places) - good sleeping weather if the humidity doesn't bother you. That's all a few degrees below the long-term averages for this time of year in Baltimore, which are in the 86/87-degree range on the top end, and 65/66 at night.

Baltimore seems to have been the focus of last night's rainstorms. One city church was struck by lightning. We could hear the thunder from the WeatherDeck in Cockeysville, but only received a bit of the water. Here at Calvert & Centre streets, however, The Sun's weather instruments picked up 0.92 inch of rain. (The station was down for a few hours this morning after some computer reconfiguration. Should be back shortly.)

And that was close to the most reported anywhere in the metro area. Hamilton reported 1.13 inches to the CoCoRHaS network this morning. Towson reported 0.92 inch. Kingsville, in Harford County, had 0.86 inch. St. Mary's County also got a good deal of rain, though probably from a separate storm cell. BWI reported only 0.37 inch up until midnight yesterday.

Sunday still looks like the best weather day of the long weekend for Central Maryland, with no rain chances in the forecast, partly sunny skies and a high near 84. The 4th comes with a 30 percent chance of showers and thunderstorms, starting after 2 p.m. and continuing into the evening. 

(SUN PHOTO/ Mauricio Rubio/Cooler-than-normal bagpipers in Catonsville parade 2008) 

Posted by Frank Roylance at 10:52 AM | Permalink | Comments (0)
Categories: Forecasts
        

Looks like the long holiday weekend will carry a risk of showers and thunderstorms clear through Saturday night, with a 30 percent risk that storms will impact the fireworks. Sunday's forecast, for now, comes with no mention of rain, so if the pyrotechnics are postponed, Sunday should be ideal. (That's what happened in 2007. Sun outdoors writer Candus Thomson snapped the pic at left at the Inner Harbor on the 5th. Amazing.)

But the highest chances for thunder and lightning come tonight, rated at a "likely" 70 percent. So far, all the convection on radar appears to be well to our west, just beginning to move into western Virginia at 4 p.m. But forecasters out at Sterling seem pretty confident things will fire up around the I-95 corridor by 8 p.m. EDT, and cross the Chesapeake by 10.

After tonight, rain chances diminish to the 20-30 percent range, save for 50 percent tomorrow night. That should allow us some sunshine, at least, and time to enjoy the mild, low-80s temperatures over the holiday weekend.

Headed for the beaches? Here's the Ocean City forecast. Looks like folks headed east will have fine weather after Thursday night. No rain in the forecast at all for the weekend, with highs in the upper 70s and low 80s. Perfect. 

Going west? The forecast for Oakland, in Garrett County looks a bit wetter and grayer. But Independence Day itself looks good. Rain chances return for Sunday. Bring a book.

Posted by Frank Roylance at 3:51 PM | Permalink | Comments (0)
Categories: Forecasts
        

The U.S. Geological Survey is reporting a small earth tremor at about 9:45 a.m. EDT this morning, measured with a magnitude of just 2.8. That's not likely to be felt by many, but is enough to detect and report. 

The center of the shaking was pinpointed in southern New Jersey, on the eastern shore of the Delaware River near Pennsville, NJ, about 8 miles south southeast of Wilmington, Del.

The quake was centered about 3 miles deep. Here's a map. Anyone feel anything?

Posted by Frank Roylance at 11:23 AM | Permalink | Comments (0)
Categories: Phenomena
        

June ended at midnight last night without having delivered a single day in the 90s. May ended the same way. Baltimore - or BWI at least, the station of record for the city - has had just three days in the 90s so far in 2009, all of them in April.

So, does that mean we're in for a "cool" summer ?  "Maybe," said Steve Zubrick, the science and operations officer for the National Weather Service's Sterling forecast office. He's been crunching the numbers for the past few months, and found the following:

1. June 2009 had the fewest 90+ days (zero) since 1979. That's only happened six times since they began keeping official records for the city - in 1886, 1903, 1916, 1972, 1979 and 2009. The average number of 90+ degree days in June in Baltimore is 5.7. Last year we had nine. The record is 18, in 1943.

2. May passed without any highs in the 90s, too. The last time May and June both stayed out of the 90s was in 1979. That's only happened four times: in 1979, 1972, 1886 and 2009.

3. So how do summers with no 90-degree weather in June turn out? Zubrick said the coolest three-month (June-August) summer period on record for Baltimore was in 1903, which saw no 90-degree weather in June. The summer of 1886 was the 6th coolest, and also had no June days in the 90s. The summer of 1912 was the 12th coolest on record, and likewise had no June days in the 90s.

4. On the other hand, that latest long-term forecast for Baltimore for this summer, issued at the end of May, called for a cooler-than-normal June, but above-normal temperatures overall for the 90-day summer period. If they're right, we're in for a hot July and August.

5. As for rainfall, April, May and June together produced 19.74 inches of rain at BWI. That ranks as the second-wettest April-June period on record for the city.

For Zubrick's complete (unofficial and preliminary) report, read on.

(SUN PHOTO/John Makely 2006)

Continue reading "May, June without 90s ... Cool summer ahead? " »

Posted by Frank Roylance at 10:28 AM | Permalink | Comments (4)
Categories: Forecasts
        

A tremendous eruption by Russia's Sarychev volcano, in the Kuril Islands, on June 12 is causing strange and beautiful violet and lavender sunsets around the northern hemisphere this week. The astronauits aboard the International Space Station shot some amazing video of the eruption as they flew over. 

The sunset colors occur when fine particles of ash and sulphur dioxide blasted into the stratosphere by the eruption begin to scatter blue light. Mixed with the reddish colors of a normal sunset, they produce the purplish hue.

Photographers in northern countries have been taking remarkable pictures of the sunsets. I'm not sure whether the particulates have made it as far south as Maryland, but it's worth watching the sunsets this week.

In addition to the unusual colors, some photos show high clouds, bright yellow bands called a "twilight arch," and tall crepuscular rays fanning out from the western horizon. Here is a gallery showing some of these phenomena.

The eruption on the remote island in the Kuril chain northeast of Japan smothered half the island in lava. Here (below) is a photo of the island, snapped today by NASA's Terra Earth-observing satellite. The gray color on the northwestern side is lava. The red in the false-color image is actually green vegetation. 

For a comparison shot, showing what the island looked like before the eruption, click here. 

Posted by Frank Roylance at 5:30 PM | Permalink | Comments (1)
Categories: Phenomena
        

Charlie, on the Eastern Shore, left a comment here this morning asking why the rivers and creeks over there have been experiencing unusually high tides in recent days:

"I wanted to ask if you have any idea why we seem to be having a month's worth of very high tides here on the Upper Choptank and Tuckahoe Creek. Its been going on day after day, super high tides one after the other. What gives? Thanks. Charlie"

Well, he's right about the tides. Below is a graph of the tides at Cambridge over several recent cycles. You can see that water levels (red lines) have been running a foot or so above predicted levels for several days - at least four high tide cycles are captured on this graph. 

The Western Shore has been seeing the same thing. Annapolis and Solomons Island are also running about a foot high. The NWS says the next several high tides will also be a foot or two above predictions. Here's this morning's tidal discussion from Sterling:

"EARLY MORNING TIDES WERE RUNNING 3/4 TO 1 FOOT ABOVE NORMAL. WATER
LEVEL AT ANNAPOLIS CRESTED JUST BELOW THE LOWEST THRESHOLD LEVEL FOR
MINOR TIDAL FLOODING AT 2.5 FEET. POSITIVE ANOMALIES SIMILAR TO
THOSE OCCURRING EARLY THIS MORNING WILL LIKELY CONTINUE FOR THE NEXT
COUPLE OF HIGH TIDE CYCLES. WILL MENTION TIDES UP TO 1 FOOT ABOVE
NORMAL IN CWF PRODUCT. MINOR TIDAL FLOODING IS NOT EXPECTED DURING
THE AFTERNOON HIGH TIDE WHICH IS THE LOWER OF THE NEXT TWO.
ANNAPOLIS WILL GET TO 1.9 TO 2.0 FEET. HOWEVER...THE FOLLOWING HIGH
TIDE CYCLE OVERNIGHT BEARS MORE WATCHING. 1 FOOT ABOVE ASTRONOMICAL
PREDICTIONS WOULD PUT ANNAPOLIS JUST ABOVE 2.5 FEET."

The blue arrows on the next graph down show wind direction. And they also reveal a persistent component out of the west or southwest. That would tend to blow water up into the Bay, and hold more of the water in at low tide.

The next chart down shows atmospheric pressure, which has been trending low in recent days. Tides tend to run higher under low air pressure.

There is also the moon to consider. The moon was "new" on the 22nd, and that would have exerted an extra tug on the tides for several days, making the highs higher and the lows lower last week. The astronomical, or lunar component, however, would have been weakening in recent days, leaving the winds as the dominant factor. The moon will become a bigger factor closer to the full moon in another week - on July 7

The persistent winds would seem to be the result in part of low pressure systems that have been lingering off the New England coast, and the Great Lakes for several weeks.

That's my take on it, anyway. Anyone else? Take any good high water photos? Email them to me at frank.roylance@baltsun.com

Posted by Frank Roylance at 10:08 AM | Permalink | Comments (1)
Categories: Events
        

It doesn't have to take six months to watch a hurricane season unfold. NASA has strung together orbital imagery of the 2008 season into a brief animation and set it all to a nice island beat.

You can find the download links here.  Unfortunately, we'll have to wait and witness the 2009 season in real time.

Posted by Frank Roylance at 2:18 PM | Permalink | Comments (1)
Categories: Hurricanes
        

You'll only be a few minutes, you think. Just long enough to run in for a box of diapers or a carton of milk. Surely you can leave the kids, or the dog in the car that long without worrying about them.

Well don't. Emergency room physicians are reminding us that our cars can become hothouses, even 130-degree ovens in as little as 10 minutes when outside temperatures are as pleasant as 80 degrees.

Such temperatures can quickly be deadly to children and pets. And it happens every year. Harried grownups are sure their errands will be quick, but they're not. Or worse, they forget the kids are even in the car, and they park for work, only to realize too late that they forgot to drop them at day care.

UPDATE: A local example of exactly this phenomenon occurred recently in Ellicott City, when a 23-month-old child was left in the family car, in the driveway, all day. She died of heat stroke.

UPDATE 2: The state Department of Health and Mental Hygiene is also reporting the death of an elderly Prince George's County man, found inside a dwelling where the temperature had climbed to 99 degrees. His death was complicated by cardiovascular disease, health officials said.

A study published in the journal Pediatrics in 2005 found that even when it was 72 degrees outside, the temperature increase inside the car can put children at risk for hyperthermia, reaching 117 degrees. And "cracking" the windows 1.5 inches made no significant difference, either in the speed of the temperature increase or the final temperature.

Here's more from Dr. Nick Jouriles, president of the American College of Emergency Physicians.:

“Putting it bluntly, leaving your child in a hot car is like leaving your child in a lit oven,” he said. “The most important thing to know is that it does not have to be brutally hot outside for it to be brutally hot inside the car.  Be especially careful if you are sleep deprived or experience changes in your schedule or your child is in the back seat, making it more difficult for you to see.

Continue reading "Your car can become an oven in 10 minutes" »

Posted by Frank Roylance at 1:15 PM | Permalink | Comments (1)
Categories: Heat waves
        

It will be hard to find anything negative to say about the weather today. Blue skies, low humidity after the dampness from overnight showers dries up, and temperatures near seasonal averages should make just about everybody happy.

We can thank low-pressure systems to our north. They're drawing air in from the west, and it's being dried and warmed as it comes over the mountains. That will keep skies mostly clear today, with highs in the mid-80s. Might be a bit breezy this afternoon, but that's just going to keep us comfortable in the sunshine.

It won't last, of course. Winds will shift tonight more to the south, bringing in higher humidities. And that will increase our clouds and our chances for showers and thunderstorms on Tuesday and Wednesday. The clouds and showers will keep temperatures comfortable - in the low 80s for the latter part of the week.

Shower risks will stick with us Thursday night into the holiday on Friday. But the 4th itself, and the rest of the weekend will be rain-free with highs in the 80s if the current forecast holds up.   

Posted by Frank Roylance at 7:57 AM | Permalink | Comments (0)
Categories: Forecasts
        

Montgomery County authorities reported around 7:30 p.m. Friday evening that a large tree had fallen on a minivan at the intersection of Connecticut Avenue and East West Highway in Chevy Chase. Three people were reported pinned in the vehicle.

A technical rescue team rushed to the scene to free the people in the van. Two did not get out alive. Here's the Associated Press story that moved last night:

BETHESDA, Md. (AP) — Montgomery County fire officials say two people were killed when a part of a large tree fell on a minivan in Bethesda.

It happened about 7:20 p.m. Friday in windy and rainy weather on southbound Connecticut Avenue near East-West Highway.

Capt. Oscar Garcia of Montgomery County Fire and Rescue says part of the tree, about two and a half to three feet in diameter, fell on the minivan, which had eight occupants.

Garcia says an adult and a child were killed. He said another child sustained serious, life-threatening injuries.

Posted by Frank Roylance at 10:46 PM | Permalink | Comments (0)
Categories: Storm reports
        

The National Weather Service has issued a Severe Storm Watch for the entire region this afternoon and into this evening as an approaching cold front begins to kick off some thunderstorms. The radar loop above was valid at 3:45 p.m. EDT

Here are the counties covered by the watch. Baltimore City is also included:

ALLEGANY             ANNE ARUNDEL        BALTIMORE
CAROLINE             CARROLL             CECIL
FREDERICK            HARFORD             HOWARD
KENT                 MONTGOMERY          PRINCE GEORGES
QUEEN ANNE`S         TALBOT              WASHINGTON

A Severe Storm Warning was issued at 3:44 p.m. for parts of Washington and Frederick counties. We can expect more as the front moves closer. 

The good news is that the passing front will take the sizzle out of this little heat wave, dropping high temperatures tomorrow back into the mid-80s, near the long-term averages for this time of year. It should also lower the humidity a bit, swinging the winds around from the west (which generally brings high temperatures at this time of year) to the north.

A second cold front due through here on Sunday could generate a few more storms, but by next week we should be enjoying pleasant highs in the mid-80s, with some sunshine and more showers possible around mid-week. Good for the garden.

Speaking of sizzle, we're reading 92 degrees as I write here at The Sun's Weather Desk. We touched 93 degrees a little earlier this afternoon. It's 90 at Dulles Airport in northern Virginia, and 87 at Reagan National.

Out at BWI-Marshall, the high so far looks like 88 degrees, a shade cooler than Thursday's high of 89. The BWI record for this date is 99 degrees, reached most recently in 1954.

Posted by Frank Roylance at 3:25 PM | Permalink | Comments (0)
Categories: Forecasts
        

The National Weather Service forecast office in Wakefield, Va. has issued a Coastal Flood Statement for the beaches from Maryland south to North Carolina (green in the map) that includes a warning of rip currents this afternoon. If you're on the sand, or headed there, it's worth a read:

MODERATE RIP CURRENT RISK IN EFFECT UNTIL 8 PM EDT THIS
EVENING...

LOW PRESSURE WELL OFF THE NORTHEAST COAST WILL SLOWLY WEAKEN
THIS AFTERNOON. HOWEVER...THE COMBINATION OF HIGH ASTRONOMICAL
TIDES...AND LINGERING LONG PERIOD SWELL WILL LEAD TO A MODERATE
THREAT FOR RIP CURRENTS TODAY FOR THE BEACHES FROM OCEAN CITY
MARYLAND...TO CURRITUCK BEACH LIGHT NORTH CAROLINA.

PRECAUTIONARY/PREPAREDNESS ACTIONS... A MODERATE RISK OF RIP
CURRENTS MEANS WIND AND OR WAVE CONDITIONS SUPPORT STRONGER OR
MORE FREQUENT RIP CURRENTS...ESPECIALLY IN THE VICINITY OF
JETTIES...PIERS AND SANDBARS. ONLY EXPERIENCED SURF SWIMMERS
SHOULD ENTER THE WATER

Posted by Frank Roylance at 1:06 PM | Permalink | Comments (1)
Categories: Forecasts
        

Are you ready for some HOT weather? Doesn't really matter. You're going to get it anyway. What has been, until now, a relatively cool June with plenty of rain is about to kick into the 90s in Baltimore. And it's not going to go away quickly.

Forecasters out at Sterling are calling for a high of 92 degrees downtown on Thursday, and readings seem likely to stick near 90 right through the weekend. The forecast highs for the suburbs are only slightly lower. And with the heat comes increasing humidity. Our Chesapeake Summer begins.

This will be the first stretch of 90-degree weather in Baltimore since that surprise heat wave in April that posted three straight afternoons in the 90s (April 25-27). And that came before we had even seen highs in the 80s! Set that freaky weather aside and this will be the first true summer weather in the 90s since last Sept. 14.

The heat comes to us as the low-pressure system that's been hanging off the Atlantic coast for days, dragging relatively cool air and showers down from the north, begins to move away. That's allowing the high that's been COOKING the South and the Midwest to move our way. Here's AccuWeather.com's take on it all.

Lemonade?

Posted by Frank Roylance at 5:06 PM | Permalink | Comments (0)
Categories: Forecasts
        

Although we seem to have passed through the biggest barrage of thunderstorms of this spring storm season, with notably sunnier weather ahead, there are always risks of thunder and lightning in Maryland in the summertime. So, here are some lightning facts to know and use, courtesy of the National Weather Service in observance of Lightning Safety Awareness Week:

What are thunder and lightning, and how are they produced? 

BY DEFINITION, ALL THUNDERSTORMS CONTAIN LIGHTNING.  LIGHTNING IS A
GIANT SPARK OF ELECTRICITY THAT OCCURS WITHIN THE ATMOSPHERE OR
BETWEEN THE ATMOSPHERE AND THE GROUND.  AS LIGHTNING PASSES THROUGH
THE AIR, IT HEATS THE AIR RAPIDLY TO A TEMPERATURE OF ABOUT 50,000
DEGREES FAHRENHEIT, ABOUT 5 TIMES HOTTER THAN THE SURFACE OF THE
SUN. DURING A LIGHTNING DISCHARGE, THE SUDDEN HEATING OF THE AIR
CAUSES IT TO EXPAND RAPIDLY.  AFTER THE DISCHARGE, THE AIR CONTRACTS
QUICKLY AS IT COOLS BACK TO A NORMAL TEMPERATURE.  THIS RAPID
EXPANSION AND CONTRACTION OF THE AIR CAUSES A SHOCK WAVE THAT WE
HEAR AS THUNDER (THIS SHOCK WAVE CAN DAMAGE WALLS AND BREAK GLASS).

So how is that giant electrical spark created?

AS A THUNDERSTORM CLOUD GROWS, PRECIPITATION FORMS WITHIN THE CLOUD
WITH MOSTLY SMALL ICE CRYSTALS IN THE UPPER LEVELS OF THE CLOUD, A
MIXTURE OF SMALL ICE CRYSTALS AND SMALL HAIL (GRAUPEL) IN THE MIDDLE
LEVELS OF THE CLOUD, AND A MIXTURE OF RAIN AND MELTING HAIL IN THE
LOWER LEVELS OF THE CLOUD.  DUE TO AIR MOVEMENTS AND COLLISIONS
BETWEEN THE PRECIPITATION PARTICLES NEAR THE MIDDLE OF THE CLOUD,
THE VARIOUS PRECIPITATION PARTICLES BECOME CHARGED.  THE LIGHTER ICE
CRYSTALS BECOME POSITIVELY CHARGED AND ARE CARRIED UPWARD INTO THE
UPPER PART OF THE STORM BY THE UPDRAFT.  THE HEAVIER HAIL BECOMES
NEGATIVELY CHARGED IS SUSPENDED BY THE UPDRAFT OR FALLS TOWARD THE
LOWER PART OF THE STORM.  THE END RESULT IS THAT THE TOP OF THE
CLOUD BECOMES POSITIVELY CHARGED AND THE MIDDLE AND LOWER PART OF
THE STORM BECOMES NEGATIVELY CHARGED.

NORMALLY, THE EARTH`S SURFACE HAS A SLIGHT NEGATIVE CHARGE;
HOWEVER, AS THE NEGATIVE CHARGES BUILD UP IN THE LOWER AND MIDDLE
PART OF THE STORM, THE GROUND BENEATH THE BASE OF THE CLOUD AND
IN THE AREA IMMEDIATELY SURROUNDING THE CLOUD BECOMES POSITIVELY
CHARGED.  AS THE CLOUD MOVES, THESE INDUCED POSITIVE CHARGES ON
THE GROUND FOLLOW THE CLOUD LIKE A SHADOW.  FARTHER AWAY FROM THE
CLOUD BASE, BUT UNDER THE POSITIVELY CHARGED ANVIL, THE NEGATIVE
CHARGE MAY BE FURTHER INDUCED.

IN THE INITIAL STAGES OF DEVELOPMENT, AIR ACTS AS AN INSULATOR
BETWEEN THE POSITIVE AND NEGATIVE CHARGES.  HOWEVER, WHEN THE
ELECTRICAL POTENTIAL BETWEEN THE POSITIVE AND NEGATIVE CHARGES
BECOMES TOO GREAT, THE INSULATING CAPACITY OF THE AIR BREAKS DOWN
AND THERE IS A DISCHARGE OF ELECTRICITY THAT WE KNOW AS
LIGHTNING.

(SUN PHOTOS by Karl Merton Ferron 2004)

Continue reading "Lightning lore, and a warning" »

Posted by Frank Roylance at 2:31 PM | Permalink | Comments (0)
Categories: Lightning
        

There may be a few isolated thundershowers around the region by this afternoon. And Thursday could produce a couple more. But the way forecasters see it, this should be a mostly sunny week. Finally.

But all that sunshine in the wake of the summer solstice is going to heat us up a lot. High temperatures by Thursday should be near 90 degrees, and the readings will stay there right through the weekend. Summer is here, with the temperatures to match - about 5 degrees above the long-term averages for late June.

The heat late this week will also likely get the mosquito populations revved up, so you may not be able to spend much time outdoors by then.

So, if you have something you need to do outside, best get it done today, or by Wednesday at the latest. I was out there cutting the grass and seeding some bald spots this morning (working a late shift this week) because I know I won't want to face it by Thursday.

Overnight lows will begin to stall around 70 degrees by Thursday, too. We may need the AC on by then to cool things down for a nice night's sleep.

Forecasters out at Sterling say the relatively cool, breezy weather we've been enjoying comes to us thanks to an unusually strong (for this time of year) low-pressure system off the New England coast. That's dragging fresh breezes down from the north. We could see gusts to 20 or 25 mph this afternoon. 

But we could also get a few little showers or storms from the same setup by afternoon as those disturbances reach the Chesapeake Bay. 

By Wednesday night, a weak cold front could pass through and set off a few more showers, but the risks are low - just 20 percent if the forecast holds up.

Posted by Frank Roylance at 11:04 AM | Permalink | Comments (1)
Categories: Forecasts