Forecast creep has pushed the National Weather Service's storm forecast upward again. The latest Winter Storm Warning out of Sterling calls for snow totalling one to two feet by Sunday morning.

Here's the latest forecast discussion. And here's the forecast for BWI. 

Foot's Forecast, meanwhile has settled on a storm total of more than 24 inches. Mr. Foot tells me he thinks that may prove to be too little. This is a very "juicy" storm, and some computer models predict accumulations closer to 29 inches, he said. That would be the storm of record for Baltimore.

Just thought you'd like to know.

I had some conversations with forecasters at Sterling this afternoon for the story we're running in the print editions on Saturday. Their best estimate at the time was 14 to 17 inches before it's all over.

No matter which of these forecasts proves accurate. we're in for a pretty good ride, the end of nearly three years of meagre snows in Baltimore. I notice the barometer has been on the skids all day, and the winds are out of the northeast. Let the wild nor'easter begin!

I will be blogging from home for most of the day Saturday, so be sure to check back here for more updates. Send me your reports and photos if you like. I'll try to use as much as I can manage. Blog traffic today, judging from the comments, has been phenomenal.

(SUN PHOTO/Jed Kirschbaum Feb. 17, 2003)

Here's the snow forecast map that Sterling published just before noon on Friday.

Posted by Frank Roylance at 7:27 PM | Permalink | Comments (13)
Categories: Forecasts
        

No sooner do I get the last post - about "forecast creep" in the accumulation predictions from Sterling - and the National Weather Service bumps its accumulation forecast for the coming storm to 10 to 20 inches. Sheesh.

A noon update to the Winter Storm Warning issued overnight for the state calls for the snow to begin  between 11 p.m. and 2 a.m. tonight, with snow continuing throughout the the day Saturday and into early Sunday. The heaviest snow is expected to fall between 8 a.m. and 6 p.m. Saturday. So much for the Christmas shopping.

Temperatures will stick in the upper 20s to low 30s throughout the day, so we should expect an all-snow event for the most part. (There has been some talk of an injection of warmer air into the storm as it cranks up, but I don't see that in the forecast.)

Add all that up and they're now talking about 10 to 20 inches of snow for Baltimore before it all ends. The special bonus will be the winds - 10 to 20 mph, with gusts of 25 to 30 mph, which will keep the snow moving around after its plowed and reduce visibility. Travel, as they say, will be "extremely treacherous."

Did I mention coastal flooding? The deep low-pressure system and prolonged northeast winds will drive Chesapeake Bay water onto the western Shore. Expect some minor coastal flooding in the usual low spots. Nothing like they're seeing from this storm in Florida today.

Posted by Frank Roylance at 12:27 PM | Permalink | Comments (52)
Categories: Winter weather
        

As often happens just before Maryland's biggest snowstorms, the National Weather Service's snowfall predictions continued to creep upward on Friday. The first predictions were issued with Thursday's Winter Storm Watch, and they mentioned "more than 5 inches." 

The Winter Storm Warnings issued overnight for the entire state advise residents to prepare for 5 to 10 inches, with "locally higher amounts possible, mainly in or near Southern Maryland."

The forecast for BWI during the daytime on Saturday now calls for 7 to 11 inches. Add in the 1 to 2 inches expected before dawn Saturday, and you get 8 to 13 inches.

Looking back, it seems to me that is a pattern for the forecasters out at Sterling. They tend to be cautious and conservative with these snow predictions, as they should be, given their responsibilities. As the really big storms close in, and our fate becomes inevitable, they begin to adjust their forecasts, and you can see the numbers begin to climb. Perhaps that's appropriate caution. Perhaps it's driven by sound science.

But it sometimes also seems to leaves them lagging behind some of the commercial and amateur forecasters, who seem to revel in the possibilities on the high side. It's good for ratings. It's good for click counts. It becomes the buzz.

And that's what seems to be playing out this morning. As Sterling weighs each model run, and forecasters add in their own knowledge and experience, their accumulation numbers begin to creep higher. Elsewhere, in the meantime, some broadcasters and commercial forecasters are talking about one to two feet of snow.

AccuWeather.com's headline this morning (if you can get to it; the site is very slow) warns of "a very disruptive Mid-Atlantic Blizzard." Its snow map (left) shows Baltimore in the 6 to 12-inch band. But blogger Henry Margusity is calling for 12 to 18 inches in Washington (and presumably Baltimore). Some of the computer models last night were even scarier, suggesting an historic dump of 24 to 36 inches.

Baltimore, at least, has never had a 36-inch snowstorm, so I think we can dismiss that as likely fantasy for us. In the mountains, maybe. Southwestern Virginia could see two feet in spots. But not here.

That said, it does look like we are in for a memorable storm. It could well be the biggest since the Feb. 11-12 snowfall in 2006 (photo above) that left 13.1 inches at the airport. If some of the higher predictions prove accurate, it could become the biggest snowfall since the record storm in February 2003, that piled up 28 inches at the airport and paralyzed the region for days.

Even a foot of snow, on top of the inch (officially, at BWI) that fell Dec. 5, and this would become the snowiest December since 1966, when 20.4 inches fell at the airport, still a record for the month. It would also become the fifth-snowiest December since record-keeping began in 1883.

December isn't often a snowy month in Baltimore. The long-term average snowfall in December is just 1.7 inches. Our snowiest months, on average, are January (7 inches) and February (6.4 inches). Here are the "snowiest December" numbers to watch as the snow piles up Saturday on your sidewalk:

December 1966:  20.4 inches

December 1904:  17.1 inches

December 1960:  15.6 inches

December 1932:  14.7 inches

(SUN PHOTO/John Makely/Feb. 12, 2006)

Posted by Frank Roylance at 10:50 AM | Permalink | Comments (2)
Categories: Winter weather
        

There doesn't seem to be a way around this anymore. The National Weather Service has posted a Winter Storm Watch for the entire state of Maryland, plus Delaware. Forecasters now expect at least 5 inches of snow in Baltimore on Saturday, with some other forecasters putting the totals at more like 8 to 12 inches.

"A WINTER STORM WATCH MEANS THERE IS A POTENTIAL FOR SIGNIFICANT
SNOW THAT MAY IMPACT TRAVEL. CONTINUE TO MONITOR THE LATEST
FORECASTS."

The storm is already cranking up in the northern Gulf of Mexico, dropping some big rains from Texas to Alabama.

From Sterling, NWS science officer Steve Zubrick told me this afternoon the storm looks pretty "impressive" on radar. "The upper level jet [stream] is starting to align better, to keep the low closer to the coast than what we were thinking a few days ago. The radar is showing a lot of moisture along coastal sections. There's precipitation already, and it covers all of the southern third of Mississipppi, all of Louisiana and most of southeast texas. It's a pretty solid [rain] shield even right now."

He expects the Sterling office will begin forecasting accumulations by Friday morning.

On Friday, the storm will emerge off the southeastern Atlantic coast, where it will intensify and begin a Saturday run up the coast, pumping Gulf and Atlantic moisture into the cold air in place along the I-95 corridor, where it will fall as snow.

Here's the latest forecast discussion from Sterling.

Here's the AccuWeather.com take on the storm. 

And here's the latest from Mr. Foot.

If it does snow, you can blame me. I wore my snow tie today.

Posted by Frank Roylance at 5:18 PM | Permalink | Comments (9)
Categories: Forecasts
        

The National Weather Service forecasters out in Sterling have finally come around, raising the snow chances for Central Maryland to 80 percent for Saturday. They're still uncertain how much moisture, and therefore how much snow, the storm will produce here. But, apparently, snow it will. Winter weather advisories, or watches, could begin to appear in the forecast this afternoon.

UPDATE 5 p.m.: The National Weather Service has posted a Winter Storm Watch for all of Maryland, from late Friday night until late Saturday night. At least 5 inches of snow is expected, with more possible. AccuWeather.com is calling for 8 to 12 inches from Washington to Dover, Del. The earlier post resumes below.

Snow fans and school kids should check out Mr. Foot's forecast. He's talking about 8 to 12 inches, with some impact on school schedules on Monday.

As we've said, there will be plenty of cold air in place. There's a low-pressure system parked over Nova Scotia, and the counter-clockwise rotation around that low is pulling a steady stream of cold air around the western side and pumping it into the Northeast. That will make it cold enough for this storm to be all snow here, with a rain/snow line - this time- well to our south and east.

The real snow-maker will be the low that is cranking up over the Gulf of Mexico. It will track east, providing another drenching for the Deep South. Then it will emerge off the southeast Atlantic coast early Saturday and begin to head north and east.

Circulation around that low will begin to pump Gulf and Atlantic moisture our way. The main snow band on the AccuWeather.com maps (that's one possible scenario, above) runs from western North Carolina, straight up the I-95 corridor to Boston. Here's another from AccuWeather's Henry Margusity, showing that he believes 3 to 6 inches could fall here.

The snow is likely to start falling here in the wee hours of Saturday morning, if the forecast holds up. Highs on Saturday will hover near freezing, so we should see some snow all day, continuing into early Sunday morning.

It's supposed to stay cold early next week, and there is some chatter about a Christmas storm. Could we have a rare Baltimore white Christmas? Stay tuned.

Posted by Frank Roylance at 7:17 AM | Permalink | Comments (29)
Categories: Winter weather
        

The National Weather Service has posted the flakey icons on its main page today, a recognition that forces are aligning to bring some sort of wintry storm to the region as early as Friday night, continuing into Sunday. Sterling forecasters this afternoon have been expanding their snow (or snow-and-rain) window. But just how significant the snowfall will be remains an open question.

Here's the setup so far:

The high pressure system building over the region today, and bringing us the blue skies and bright sunshine, will begin to move away on Friday. But while it remains, we will be getting brisk northwest winds in the clockwise flow around the high - an open door to cold air from Canada. We're running something like 8 degrees below normal today at BWI.

The clear skies will mean lots of radiational cooling overnight, and lows in the low- to mid-20s. So, as the high begins to slide away, we will have plenty of cold air in place as the weekend opens.

The next shoe to drop will be the development of another coastal low, the latest in a series this autumn that are typical of our weather during an El Nino winter. The Pacific Ocean phenomenon sends the sub-tropical jet stream across the lower portion of the continent, grabbing plenty of moisture from the Pacific, then the Gulf of Mexico and the Atlantic and packing it into storm systems that skirt the Gulf Coast, and then come marching up the East Coast.

(New Orleans is having a record-wet December - 22 inches! BWI has already topped 4 inches for the month, and nearly 52 for the year. The 1.41 inches of rain that fell on Dec. 9 set a new record for the date, breaking the old mark of 1.08 inches, set in 1991.)

When those storms reach the mid-Atlantic during an arctic outbreak, the resulting precipitation can mean snow. And sometimes it means lots of snow.

But as we're told every winter, everything depends on how cold the air in place is, and where the storm's center actually goes. And at this point, forecasters and their models remain somewhat uncertain about the storm track. The map above shows where the highest Sunday snow probabilities are, for now, in the forecast model ensemble.

Forecasters are beginning to lean toward a path that moves the storm's center off the coast sooner, rather than later. Here's some of today's discussion from Sterling. Brackets are my translations of weather-ese:

"[Computer models) ARE STARTING TO COME INTO BETTER AGREEMENT WITH THE
TRACK OF THE SYSTEM...BUT CONSIDERABLE SPREAD/UNCERTAINTY STILL
EXISTS. LATEST THINKING IS THAT THESE SYSTEMS [the coastal storm and a reinforcing disturbance from the Midwest] WILL PHASE BUT
LATER THAN SOONER...RESULTING IN A TRACK FURTHER S/E AND AWAY FROM
THE COAST. THIS COLDER SOLUTION WOULD PROVIDE A GLANCING BRUSH OF
WINTRY PRECIP DURING THE SAT THRU EARLY SUN. TIME FRAME."

And from an earlier NWS discussion: "The cold air that will be reinforced for the latter half of this week will be ample throughout the column for snow across much of the area, and a mix closer to the bay, Southern Maryland and adjacent areas overnight Saturday and into early Sunday. This activity will be forced off the mid-Atlantic coast into the late morning, early afternoon hours."

We'll just have to wait and see how far inland the snow reaches. Officially, Sterling is rating our snow chances at 30 percent. The forecast low for Sunday morning at BWI is 26 degrees. The Sunday high is 37.

AccuWeather.com offers two possible scenarios for the weekend. Both bring us some snow, but one (map above) brings a more "substantial" storm, smack-dab on the I-95 corridor. But their snow blogger, Henry Margusity, seems to have some doubts about the impact of this storm. He does drop a hint about a Christmas storm, however.

Here's Mr. Foot's offering on the weekend snow.

Posted by Frank Roylance at 2:35 PM | Permalink | Comments (2)
Categories: Forecasts
        

Looks like we will have a very pleasant and unseasonably mild start to this week, with a high near 50 degrees today and in the mid-50s on Tuesday. But a cold front is due to pass by late on Tuesday, dropping daytime temperatures into the low 40s by Wednesday - about 5 degrees below normal for BWI at this time of year. The lows will sink into the near-normal mid-20s.

The good news is that skies will remain sunny for pretty nearly the entire week, if the forecast holds up. The only smudge on the forecast is the "mostly cloudy" forecast for Tuesday as the front passes. But there is no rain at all expected from the frontal passage, or right through the weekend.

And that will be a nice break, indeed. Baltimore-Washington International Thurgood Marshall Airport has recorded 51.86 inches of precipitation so far this year. That is nearly 10 inches of surplus beyond the 41.94-inch average for an entire year. (The surplus is the dark green area in the chart). It is very close to becoming the fourth-wettest year in the past 30 years at BWI.

2003:  62.66 inches

1979:  58.98 inches

1996:  58.31 inches

1989:  51.88 inches

2009 (to date):  51.86 inches

Average (full year): 41.94 inches

Average (to Dec. 14): 39.96 inches

Posted by Frank Roylance at 10:47 AM | Permalink | Comments (1)
Categories: Forecasts
        

Cold weather brings scarcity for many, both human and avian. And we all need to look out for each other in hard times.

A story I wrote for last Sunday's Sun, about a big crow roost near Loch Raven Boulevard and The Alameda (left), caught the attention of Sun reporter Fred Rasmussen. Fred spent some time this week watching a pair of crows working together to keep themselves fed for another day. Here's his tale:

"Frank: I loved your crow piece. While I was off earlier this week, I observed several crows who had found three ears of corn, tied together, that had been used as a fall door decoration.

"One crow kept dropping it in the street until its kernels started to pop off, which they ate with vigor. Then they separated the ears - so each crow could munch on their own ear. It was an incredible performance. Birdbrain? I don't think so. Cheers! Fred."

Anyone else have a good crow story?

(SUN PHOTO/Kim Hairston)

Posted by Frank Roylance at 11:59 AM | Permalink | Comments (14)
Categories: Phenomena
        

The cold, dry air that has moved into the region will keep Baltimore temperatures in the 30s on Friday. Radiational cooling tonight will drop the lows into the single digits in the Potomac Highlands, and into the teens in the northern and western suburbs of Baltimore and Washington.

This morning's low of 22 degrees at BWI (it was 24 here at The Sun) was the coldest airport reading since March 5, when the low was 18 degrees. Tonight's forecast low for the airport is 19 degrees. Bracing.

For stargazers, all this cold, clear air is great news. It's an open window to the bright winter constellations - Orion (left) most prominent among them - now coming into view in the evening. Jupiter is still bright in the southwest in the evening, too, and Mars is becoming amazingly bright and red in the east late in the evening as it approaches opposition late in January.

The annual Geminid meteor shower - arguably the best of the year if it weren't so darn cold - is also on tap for Sunday night into Monday morning, peaking around midnight EST. The Geminids have been gaining steadily in their activity in recent years (see chart), now topping 130 per hour at their peak under ideal dark-sky conditions. 

UPDATE: Well, if the skies are cloudy, you can try listening for the Geminid meteors. You can actually hear them on the radio. Here's a tip from Herman Heyn, Baltimore's Streecorner Astronomer:

"In the east it looks like the clouds won't allow
them to be seen. But here's an idea. You can try hearing
radar pings from them on your computer. Go to
<www.spaceweather.com> and click on
"Spaceweather radio". The later in the evening
the better, I believe.** They peak around midnight
our time (Dec. 13/14). For an update on the shower,
itself, click on "Geminid meteor shower".
Best regards,
Your Street Corner Astronomer"

Earlier post resumes:

But the weather forecast for Sunday night is not promising. The day will likely start with some mixed wintry precipitation, changing over to all-rain by late morning. The overnight forecast isn't much better.

So, if you want to catch of glimpse of the Geminids this year, tonight may be your best shot. The shower is active between Dec. 7 and 17, so the activity is already ramping up toward Sunday's midnight peak. Reader Corine Schramke is thinking along the same lines:

"Frank: As I stepped outside to call my dog in last night, I saw a meteor streak across the sky. Looking at the forecast, tonight might be the best time for sky watchers in our area to bundle up and go out to look. It's a shame that the peak meteor showers this year seem to have all occurred during cloudy nights. But then, with all the rain we've had, maybe that isn't a surprise, either!  Happy sky watching!"

Bundle up, indeed. In addition to the lows in the teens and 20s, winds will be blustery, especially earlier in the evening. The meteors will appear to radiate from the twin stars of Gemini, Castor and Pollux, rising in the northeast after 8 p.m. The best time to look may be around midnight when Gemini is high above the eastern horizon.

If you miss the show tonight, the next clear night in the forecast is next Wednesday.

Posted by Frank Roylance at 10:57 AM | Permalink | Comments (5)
Categories: Forecasts
        

Four Marylanders have died already this autumn under circumstances in which cold weather has played a role.

The state Department of Health and Mental Hygiene said Thursday the Office of the Chief Medical Examiner has ruled that hypothermia - low body temperature - was a contributing factor in the deaths of a Baltimore woman on Nov. 21; a Montgomery County man a week later; an Anne Arundel County man on Nov. 30, and a Baltimore County woman on Dec. 4.

There was no information on the other circumstances surrounding these deaths. But in past years, health authorities have said that most deaths involving hypothermia also involve such factors as advanced age, alcohol consumption, cardiovascular disease and dementia.

These four deaths were the first, but more are sure to follow. Last year the state counted 54 deaths involving hypothermia.

"Just a little preparation and common sense will keep you and your family safe and warm during the days and nights of sub-freezing temperatures this winter," said Maryland Health Secretary John M. Colmers. "We can save lives in severe weather by keeping our eyes open and checking our friends and neighbors, especially seniors.

Deaths from hypothermia do not require extremely low, or even freezing temperatures, only exposure to the cold, even indoors due to inadequate, failed or unused heating systems. The days on which these four Marylanders died were not particularly cold for this time of year. Here are the highs and lows at BWI for each of the deaths.

Nov. 21:  High 58  Low 39

Nov. 28:  High 50  Low 34

Nov. 30:  High 58  Low 38

Dec. 4:  High 48  Low 34 

The average highs for these dates are in the low 50s; the average lows are in the low 30s.

This weekend promises the coldest weather so far this season, with a low of 19 degrees forecast for Friday night into Saturday morning.

(SUN PHOTO/Kenneth K. Lam 1994) 

Posted by Frank Roylance at 10:42 AM | Permalink | Comments (4)
Categories: Winter weather
        

There is a wind advisory posted for the region late today as deep low pressure  to our north (the barometer in Baltimore is currently a low 29.24 inches) drags a cold front through the area. Here's the scoop:

"A WIND ADVISORY REMAINS IN EFFECT UNTIL 1 AM EST THURSDAY.

"A DEEP LOW PRESSURE SYSTEM TO THE NORTH WILL BRING A COLD FRONT
TO CROSS THE AREA LATE THIS AFTERNOON AND EVENING. STRONG AND
GUSTY WINDS FROM THE WEST AND SOUTHWEST WILL DEVELOP BEHIND THIS
FRONT. GUSTS UP TO 50 MPH WILL OCCUR. THE GROUND WAS SATURATED BY
HEAVY RAINS OVERNIGHT...AND DOWNED TREES WILL BE LIKELY"

Posted by Frank Roylance at 3:35 PM | Permalink | Comments (0)
Categories: Watches and warnings
        

The 2009 hurricane season has been over for exactly 9 days and already an intrepid band of forecasters has issued its predictions for 2010.

Phil Klotzbach and William Gray, at Colorado State University, say the El Nino event that was blamed for suppressing hurricane formation during the 2009 season (and influencing this stormy autumn we've had) will wane by next summer.

That, they say, will take the brakes off the underlying conditions - warm sea surface temperatures in the tropical Atlantic - that have been sending us unusually active Atlantic seasons, on average, since 1995.

So, nearly six months out, the CSU team expects to see 11 to 16 named storms next season. Of those, 6 to 8 will reach hurricane force, with 3 to 5 of those reaching Cat. 3 strength (111 mph).

The long-term averages are: 9.6 named storms; 5.9 hurricanes; 2.3 "intense" (Cat. 3) storms.

Their December forecast predicts a 40 percent chance that at least one major (Cat. 3) storm will make landfall along the East Coast, including Florida's Atlantic coast. The long-term average is 31 percent. 

It's the first time Klotzbach and Gray have used number ranges in their initial forecast. They say they will list specific numbers in their next update, in April.

The CSU forecasts are based on 58 years of data on hurricanes and air and water conditions in the Atlantic basin. They claim their system has correctly forecast above- or below-average seasons in 44 of those 58 years.

Time will tell. In the meantime, here's an interesting take on the surprising amount of Maryland damage done by Ida, the Gulf hurricane remnants that stalked the U.S. East Coast in November. That's the Calvert County shoreline of the Chesapeake above, where a storm surge driven by Ida's passage eroded many feet of beach.

(Photo by Karl Hille, for NASA)

Posted by Frank Roylance at 1:12 PM | Permalink | Comments (0)
Categories: Hurricanes
        

Woke up this morning to the sound of heavy rain on the roof and, soon after, a forecast of more rain, and more snow chances for late Saturday into Sunday. Nothing dull about this autumn's weather so far.

So I drove out to Loch Raven Dam (above, and left), where the water was roaring over the top and flooding portions of the valley below. (Many thanks to the very nice Baltimore County police officer who did not give me a parking ticket.) The Jones Falls (below) was over its banks, too.

More immediately, we're looking for minor coastal flooding as southerly winds and heavy runoff push high tides as much as two feet above the predicted levels. Then there will be gale-force winds, a chance for thunderstorms (and more rain) in parts of the state this afternoon as a cold front passes behind the storm. And once the front passes, we'll see plummeting temperatures ahead of the weekend snow.

Where to start on this storm, which has clobbered much of the country with rain, wind and snow.?

The rain. We measured about 1.5 inches on the WeatherDeck in Cockeysville overnight. BWI airport reported 1.71 inches, which is almost exactly what we had in our gauge here at The Sun, North Calvert and Centre streets. It fell at rates exceeding 1.1 inch an hour at times. 

For the month, the airport has seen almost 4 inches of rain, well above the 3.35-inch average for the entire month at BWI. The total for 2009 is now about 51.5 inches. That makes this the fourth-wettest year in the last 20 years, after:

2003:  62.66 inches

1996:  58.31 inches

1989:  51.88 inches

Many locations on the Eastern Shore reported well over 2 inches of rain overnight. Here are the totals from CoCoRaHS.  Closer to Baltimore, the rain totals ranged from 1.08 inches in Ellicott City, to 1.76 inches in Sverna Park, to 1.96 inches in North East, up in Cecil County.

As the cold front approaches today, we will remain on the warm side of this storm, with persistent winds from the south pushing water up the Chesapeake Bay and holding it there. That is going to mean minor coastal flooding along the western shore. The NWS has issued a Coastal Flood Advisory from Harford to St. Mary's counties, forecasting high tides two feet above normal levels. (Annapolis tide graph below.)

A Gale Warning is also up today for the lower tital Potomac River and lower portions of the Chesapeake Bay.

Then there's the snow. Forecasters say once the cold front blows through this afternoon, temperatures will drop as "modified" arctic air pours in. The overnight low forecast for Baltimore on Friday night into Saturday morning is 21 degrees. A quick-moving disturbance will pass to our south, strengthening a developing coastal low. There's a 30- to 40-percent chance that will bring us "accumulating snow" late on Saturday into Sunday. No depth predictions yet, but the storm is described as "brief."

Beyond the weekend, forecasters see more arctic air arriving early next week.

(SUN PHOTOS by Frank Roylance)

Posted by Frank Roylance at 11:23 AM | Permalink | Comments (3)
Categories: Forecasts
        

Some of the biggest surf in decades -30 to 40 feet - is rolling onto the north shore of the Hawaiian Islands. And surfers - crazy? brave? suicidal? You tell me - are all over them. Here is some jaw-dropping footage shot today at Pe'ahi and posted on You Tube by Billabong (www.BillabongXXL.com).

Surf News put it this way: "Sean Collins, head forecaster for Surfline.com, said this swell ranks in the top five biggest ever experienced on Oahu's North Shore, comparable to historic El Niño-fueled episodes in 1998 and 1969. The extreme surf is expected to continue for several days with High Surf Advisories issued for all north-facing shorelines of the entire Hawaiian Chain. The swell is so powerful forecasters expect it to significantly impact the West Coast of North America in the coming days, reaching California on Wednesday and Mexico on Thursday, working its way south throughout the Pacific until finally reaching Chile over a week from now."

Posted by Frank Roylance at 8:40 PM | Permalink | Comments (2)
Categories: Cool pictures
        

Oh my. What a forecast Sterling has dished up today. Don't let the sunshine this morning fool you. There's a real mess headed our way late today and tomorrow.

Depending on where you are, there may be a Flood Watch, a Winter Storm Watch or a Winter Storm Warning posted for your area. And forecasters are already watching the next round of wintry weather - another coastal storm with a 30 percent chance for snow here on Saturday.

Are we having fun yet? (The school kids are. Here's the discussion at Foot's Forecast.)

First on the menu is that huge storm system that came ashore in Southern California (left) yesterday. It's now grinding across the continent with heavy snow and rain, and deep cold in the northern Plains. (It was 33 degrees BELOW zero this morning in Havre, Montana.) Some mountain locations are expecting 3 to 4 feet of snow.

The storm should begin to affect us late today as the storm's center moves toward the Great Lakes, staying to our west and keeping us on the warmer, wetter side of the circulation.

Forecasters say it should begin around dinnertime here, with snow and sleet for the I-95 corridor. That will change to rain and sleet during the late evening, and then to all rain before midnight as surface temperatures rise.

The rain, fueled by copious moisture from the Gulf of Mexico and the Atlantic, could be moderate to heavy at times. Widespread amounts of 1 to 2 inches are expected, with some locations receiving as much as 3 inches. A Flood Watch has been issued for all of the Western Shore, from Harford to St. Mary's counties, westward to Frederick and Montgomery, and for the Lower Eastern Shore. Watch for small streams to overflow their banks, and for more standing water in poorly drained and urban areas.

Farther north and west, including Baltimore's northern and western suburbs up to the Mason-Dixon Line, the cold air at the surface and frozen precipitation will linger longer, posing more of a hazard to travelers. A Winter Storm Watch is posted for Carroll, Frederick, Montgomery and Washington counties, where freezing rain could accumulate up to a quarter-inch of ice. 

The most significant ice accumulations are expected still farther west, in Allegany County, where temperatures at the surface may stay near freezing for most of the night, increasing the risk of freezing rain. The NWS has posted a Winter Storm Warning for Allegany until  7 a.m. Wednesday.

Had enough yet? Wait. There's more.

After this storm moves off, temperatures in its wake will drop sharply. High temperatures will slip through the mid-30s for the rest of the week, with overnight lows falling to 20 degrees by Friday morning.

With that cold air in place, the next system could deliver another Saturday snowstorm. It's too soon for guessing accumulations. Chances for snow in Baltimore are put at 30 percent for now. But forecasters do expect higher amounts this time will be in the southern counties, closer to the coastal low that's expected to develop.

And winter is still two weeks away! 

(AP Photo/Marcio Jose Sanchez, Monday)

Posted by Frank Roylance at 10:54 AM | Permalink | Comments (6)
Categories: Forecasts
        

"Desperate" as we are for more rain, the forecasters out at Sterling are cooking up a pretty good helping for late Tuesday into Wednesday.

The source this time is a big Pacific storm, now moving into Southern California (map), that will be making its way across the country over the next 48 hours. The powerful low will generate snow and some blizzard conditions across parts of the country's midsection, rain farther south, and there's a potential for some severe weather in sections of the Deep South.

But as the center of the low swings north and east into the Great Lakes, we will be on the warm and very wet side of the circulation. That should mean all rain for Baltimore (AccuWeather.com map, right), with more of a "wintry mix" changing to rain in the western counties.

UPDATE: The national Weather Service today issued a Winter Storm Watch, calling for an ice storm, Tuesday evening through Wednesday morning, from Carroll and Montgomery counties westward to Garrett County:

"PRECIPITATION IS EXPECTED TO BEGIN TUESDAY AFTERNOON IN THE
CENTRAL SHENANDOAH HIGHLANDS AS A PERIOD OF SNOW...MOVING NORTH TO
THE PENNSYLVANIA BORDER EARLY TUESDAY EVENING. PRECIPITATION IS
EXPECTED MIX WITH SLEET...BECOME HEAVIER TUESDAY EVENING AND
CHANGE TO RAIN. HOWEVER TEMPERATURES AT THE SURFACE WILL STAY
BELOW FREEZING...SO RAIN THAT FALLS WILL FREEZE ON IMPACT.
FREEZING RAIN IS EXPECTED TO CONTINUE THROUGHOUT TUESDAY NIGHT
BEFORE WARMER AIR MOVES IN WEDNESDAY MORNING.

"ONE QUARTER INCH OF FREEZING RAIN ACCUMULATION IS POSSIBLE. THE
MOST LIKELY PLACE TO RECEIVE THAT MUCH WOULD BE IN THE COLDER
LOW LYING AREAS OF THE SHENANDOAH VALLEY AND ALLEGHENY HIGHLANDS.

"A WINTER STORM WATCH MEANS THERE IS A POTENTIAL FOR SIGNIFICANT
SNOW...SLEET...OR ICE ACCUMULATIONS THAT MAY IMPACT TRAVEL.
CONTINUE TO MONITOR THE LATEST FORECASTS"

Earlier post resumes:

Here's how they expect it to play out:

We'll continue to enjoy some sunshine today, and get rid of most of the snow and ice that remains. Cold air moving into the western counties is triggering some lake effect snow showers and flurries in the higher elevations into this evening.

The clouds will move in tonight and tomorrow ahead of the mid-week storm, which will be cranking up in the southern plains on Tuesday and move toward the Great Lakes by Wednesday morning.

The counter-clockwise flow around the low will drag lots of warm, wet air north from the Gulf of Mexico and the Atlantic, which will fuel our rain. Up to an inch is possible Tuesday night.

What's less certain is how long it will take this warmer, wetter air to "erode" the cold air that's now in place. Overnight lows on Tuesday/Wednesday will be close to the freezing mark. That could mean we start with freezing rain or sleet.

"Current feeling is that precipitation will begin in the form of a wintry mix late Tuesday afternoon/Tuesday evening before gradually changing over to all rain early Wednesday morning," the forecasters said. 

Western counties have the best chance for any of the frozen stuff to accumulate. "And the best chance for significant icing from freezing rain will be from the Blue Ridge mountains westward," forecasters said. That seems to leave the Baltimore-Washington metro areas mostly in the clear as far as ice. That is, if the forecast holds up.

Here, they said, "precipitation will likely be in the form of rain south and east of I-95, with a wintry mix north and west of I-95 changing to rain. The best chance for any significant snow/ice accumulations will be across north-central Maryland near the Mason-Dixon Line."

Up to a half-inch of additional rain is possible here during the day on Wednesday as another cold front blows through behind the storm. That will bring clearing, but colder weather, with daytime highs in the 30s, and lows in the 20s, from Thursday through the weekend.

Posted by Frank Roylance at 11:36 AM | Permalink | Comments (1)
Categories: Forecasts
        

The official measurement on Saturday's snowstorm for Baltimore came to a whopping 1 inch. The National Weather Service's station of record for the city is at Baltimore-Washington International Thurgood Marshall Airport, which was on the rainier, warmer side of this very varied storm.

But the snowfall map issued Monday by the forecast office in Sterling shows what we all already know - that the totals north and west of the airport were considerably deeper. Some locations within Sterling's forecast area reported as much as 8 or 9 inches of snow.

Parts of Carroll and Montgomery counties measured 6 and 7 inches. Locations closer to Baltimore ranged from an inch near the city, to 5 inches in the western suburbs of Baltimore County. Here are some more reports from across the region, from CoCoRaHS. Be sure to change the date to Dec. 6, and click on "New Snow." Some highlights:

Clarksburg, Montgomery Co.:  7.5 inches

Sykesville, Howard Co.:  6 inches

Mt. Airy, Carroll Co.: 5.5 inches

Ellicott City, Howard Co.: 4.1 inches

Cockeysville, Baltimore Co.:  3.1 inches

Severn, Anne Arundel Co.:  2.5 inches

Bowie, Prince George's Co.:  2.5 inches

Hamilton, Baltimore City:  1.1 inch

The distances between hardly any snow and considerable accumulations were often quite small. We had less than 2 inches on the WeatherDeck in Cockeysville, but when we went to see friends for dinner in May's Chapel Saturday evening, they had what looked like 4 inches on their front yard.

And that's pretty much what forecasters had led us to expect. In fact, the forecasting on this quirky storm seems to have been quite good as it approached - from the timing, to the predicted accumulations, to the sharp differences in snow totals across small distances. Well done, Sterling.

(Photo courtesy of Gregory Hill, Owings Mills. Taken Sunday morning.)

Posted by Frank Roylance at 10:55 AM | Permalink | Comments (2)
Categories: Winter weather
        

The U.S. Geological Survey is reporting a small earthquake at about 7:27 p.m. EST Sunday 13 miles from Milledgeville, Ga., southeast of Atlanta. The very shallow tremor was measured at Magnitude 3.2.

Eastern Georgia and especially South Carolina have been the sites of numerous small, and a few very big earthquakes over the past few centuries.

An 1886 quake in Charleston, S.C. killed scores of people, did tremendous damage and was felt as far away as Boston, Bermuda, Chicago and Cuba.

Here are some details on last night's tremor. Here are some more maps.

And here is some information about the history of earthquakes in Georgia.

Posted by Frank Roylance at 10:39 AM | Permalink | Comments (0)
Categories: Earthquakes
        

Well now, wasn't that a nice little snowstorm? With the snow winding down across the region, the coastal low moving off, and the barometer bottoming out, it looks like we're about done. There's about 1.75 inches out on the WeatherDeck. The grass is white but the walks and roads around here are just wet or slushy.

All the same, there were kids out on the hill at Greenwood, on North Charles Street. The sledding looked a bit sticky and slow, but hey ... you take what you can get around here.

Here are some snow measurements from around the region, some of them taken earlier in the day. The local winner appears to be Woodlawn, with 5 inches. Feel free to send in comments with your own reports.

Skies should begin to clear off tonight, and we'll have sunshine on Sunday. This stuff should be gone quickly.

(SUN PHOTO/Frank Roylance)

Posted by Frank Roylance at 4:31 PM | Permalink | Comments (3)
Categories: Winter weather
        

UPDATE: The National Weather Service has issued a Winter Weather Advisory from the Western Shore to Allegany County. Expect 1 to 2 inches of snow Saturday in Baltimore. Points north and west of the urban corridor could see 2 to 4 inches; to the south and east, little to no accumulation. Earlier post below. 

Another storm spinning up in the eastern Gulf of Mexico is expected to be off the Carolina coast by Saturday morning, raising the chances for some snow in Baltimore on Dec, 5. That would be the sixth time that's happened in the past eight years (or the seventh, if you factor in the Leap Year in 2008, when a trace of snow was noted at BWI on the 6th).

The forecast this morning calls for a "slight chance" for rain at BWI after 3 a.m. Saturday morning, changing to snow by dawn, then "rain and snow likely" between 9 a.m. and 3 p.m.

The precipitation would change back to all snow by late afternoon, continuing into the evening - if the forecast holds up. The chances, for now, are put at 80 percent.

AccuWeather.com, as we've come to expect, puts an edgier spin on the forecast, calling for 1 to 3 inches west of I-95, with travel delays, wet-to-slushy highways. (Map at left.) For a calmer analysis, check out Mr. Foot's forecast. He sees an inch. Maybe.

From there - Sunday through Tuesday - things look sunny, with highs in the 40s and lows near freezing.

Once again, precisely what happens Saturday, where it happens and when, will all depend on a delicate balance of timing, the storm track up the coast, and the interplay of temperatures aloft, where the snow will form, and near the surface.

Forecasters say it will "definitely" be cold enough to form the snow aloft as the counter-clockwise spin of winds around the storm draws cold air into our region from the north. But temperatures at the surface will range from the middle 30s in the western suburbs, to the lower 40s in Southern Maryland. On balance, expect flakes in the air west of the cities, and a rain/snow mix east of the urban corridor. For BWI, forecasters are predicting "less than one inch" of accumulation.

Nothing to worry about; just another Dec. 5 with flakes in the air, and perhaps a hint of snowier days to come.

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

Paul M. Novak Jr., of Baltimore, sent me this beautiful photo he shot over the weekend. He said:

"I was in Ocean City this weekend and caught and unexpected shot of a rainbow over the Ocean. It was a very blustery day, and just a real brief shower had passed through the area. I looked out of the hotel and here is what I managed to capture !"

Also in my mail this morning was this sort-of-related note, from Kevin Manning:

"As we approach 50" of rain for the year, can you inform us on the historical records for yearly rainfall? We are nearly 10" above the long-term average, so far this year."

The precipitation total for the year at BWI-Marshall Airport has nearly topped 49 inches. The long-term average for the airport for an entire year is 41.94 inches. So, after a bit more than 11 months, we are already nearly 7 inches above the yearly average. With just average precipitation in December we should have a 10-inch surplus for the year.

(Year-to-date for Seattle, Wash.: 35.69 inches. That city's reputation for rain is misunderstood. While they have many gray, damp days, the accumulations are generally small, summers are dry, and annual totals are modest.)

But remember that as wet as it's been in Baltimore since April, we began the year very dry, and ended March in drought. So, we are still a long way from record territory, and we'll need a deluge in December just to break into the top five wettest years on record (since 1871) for Baltimore:

2003:  62.66 inches

1889:  62.35 inches

1979:  58.98 inches

1996:  58.31 inches

1952:  56.57 inches

Posted by Frank Roylance at 8:03 AM | Permalink | Comments (12)
Categories: By the numbers
        

Clouds are thickening overhead as a Gulf storm moving north and east along the Appalachians begins to affect our region. (See radar loop, below.) By this afternoon, we should see the rain begin to fall, delivering as much as an inch before it races off to upstate New York and we begin to dry out on Thursday.

We'll be on the east side of the storm's center, which means we'll see the milder, wetter portion of this weather event. Forecasters out at Sterling are even suggesting we'll hear some thunder after midnight as the mild air gets unstable and triggers a few thunderstorms.

The winds from the south will also drive more water up the Chesapeake and hold it there. That will mean some high water at high tides into Thursday. But there are no flood warnings yet.

Once this storm blows away, we'll get some 25 to 30 mph winds from the west, and clearing skies on Thursday and Friday. Rain on the western slopes of the Alleghenies will change to snow overnight into Friday, however, with "up to a couple inches of snowfall expected for some prime upslope locales," forecasters said.

Here on the east side of the mountains, we can expect colder temperatures, from the mid-30s to near 40 degrees overnight into Saturday. And that will set us up for the next event.

On Saturday morning, another coastal storm will be cranking up off Hatteras. The counter-clockwise flow around that low will send plenty of ocean moisture into our region. And with fairly cold air in place, forecasters still think that could produce some sort of wintry mix. Here's how they phrased it in this morning's discussion:

"Broad cyclogenesis off the Carolina coast expected Saturday morning. Some areas of banded precipitation extending northwest into the [forecast area] expected. Temperatures cold enough for snow except over the bay. Included some low chances [in the forecast] for snow or rain/snow mix. Impact potential looks low at this time, though the situation will continue to be monitored closely."

Here's a very impressive analysis of the approaching winter weather by Mr. Foot's panel of area science students. 

Posted by Frank Roylance at 10:54 AM | Permalink | Comments (0)
Categories: Forecasts
        

Enjoy all this sunshine today (Tuesday) because the rainy weather we've come to know and love this fall will move back into the region after lunchtime on Wednesday, as a Gulf storm moves inland and rides north and east along the west side of the Appalachians.

Then, if you wear your jammies inside-out, and put a spoon under your pillow, we might - just maybe - see snowflakes sometime on Saturday - the 5th. If we get at least a trace, it would be the sixth time in eight years Baltimore (BWI) has seen snow on Dec. 5th. More on that shortly.

First, we can bask in the late-autumn sunshine as high pressure moves across the region today before moving offshore tonight. Temperatures will reach the low 50s, which is about average for this time of year in Baltimore.

But as the Gulf low moves closer, clouds will begin to increase, and the rain could begin sometime after lunch on Wednesday, forecasters say. The low will pump plenty of mild air and Gulf moisture into the region on south winds, with up to an inch of new rain possible late Wednesday into Thursday. That will come on top of the 1.8-inch surplus from November in a very wet year.

Colder, drier air moving into the region once the storm rolls into upstate New York will bring upslope snow to the western counties on Thursday. Temperatures here will drop from the 60s to the lower 50s on Thursday. Forecasters say it will be cold enough Friday for all-day snow showers in the high elevations of the Alleghenies.

Then, on Saturday, another coastal low is forecast to develop off Hatteras. "Banded precipitation, certainly cold enough for snow, could expand into our [forecast] area," forecasters said Tuesday morning. "Timing and position uncertainty with this low still fairly high ... Slight chance for snow for the Balto-DC metro areas and west with chance for rain/snow for southern Maryland for Saturday ... Struggling to reach 40 [degrees] F for areas east of the Blue Ridge."  

For now, the official forecast calls for a "chance of showers" and a high of 42 at BWI. Here's AccuWeather.com's take on the prospects for Saturday.

UPDATE: Here's more from the NWS afternoon discussion:

"NEWEST GUIDANCE RETREATING A BIT FROM
EARLIER RUNS THAT HAD MORE OF A WINTRY SYSTEM FOR MID ATLANTIC ON
SAT/SUN. TRENDS NOW SHOW A WEAKLY FORCED AND REGIONAL-SCALE AREA OF
LIGHT PRECIP SPREADING OVER THE MID ATLANTIC AS THE SURFACE LOW SPINS WELL
OFF THE ATLANTIC COAST SAT INTO SUN. FOR NOW A LOW CHANCE EVENT W/ A MIX
OF RAIN/SNOW FOR LATE SAT /MAINLY RAIN DURING THE DAYTIME HOURS AS
TEMPS ARE EXPECTED TO TOP-OUT IN THE UPPER 30S-LOW 40S."

(SUN PHOTO/Amy Davis/Dec. 6, 2005)

Posted by Frank Roylance at 11:17 AM | Permalink | Comments (3)
Categories: Forecasts