Moderate to sometimes heavy snow rolls on 1000 6FEB10

Posted at 10:00 AM ET, 02/ 6/2010

Many of our best storms conclude with a final snow thump when the upper-level energy swings through and interacts with the moisture from the coastal surface low -- this one fits the bill. As temperatures continue to cool aloft and at the surface, the previously moisture-laden snow has transitioned into a fluffier and more powdery one. Accumulations are now ranging from over a foot to around two feet, leading to downed trees and wires which have helped cause numerous power outages.


Heavy wet snow continues to pile up in Cleveland Park this morning. Photo by CWG photographer Ian Livingston.With the low pressure slow to move out and still pumping moisture back into cold air, another general half-foot of snow should fall with some spots getting more and others perhaps less. It is likely that much of the snow from here out will be moderate until it starts to taper this afternoon, but there will also be embedded heavier bands capable of producing 1-2"+ per hour. One rather large band is currently drifting in from the north and will slowly move southeast through the entire area during the midday into early afternoon.

Posted at 05:30 AM ET, 02/ 6/2010
Metro Forcast
Today: Snow ending late, windy. Total accumulations 16-26". High near 30. | Tonight: Gradual clearing, breezy and cold. 10-16. | Tomorrow: Mostly sunny. Near 30. | A Look Ahead | Get Express Forecast by E-mail

Generally 12 to 18 inches of snow has fallen across the metro region (with a few spots over 20") and we still have the final 1/3 of Snowmageddon to go. Steady, wind-driven snow will continue into the afternoon, boosting snow tallies to historic levels. The snow is likely to finally taper in the mid-to-late afternoon, with only lingering flurries by dark. Day time accumulation should range from 5-8 inches (locally higher where heavy bands set up, mainly north of town), with the lightest amounts south of the beltway. Total storm accumulations will likely fall in our predicted range of 16-26 inches throughout the region, though a few areas (e.g. upper Montgomery and Loudoun counties) could total 30" or so.

Gusty winds from the north will cause blowing and drifting snow -- that is, blizzard conditions. Winds will generally be sustained at around 20 mph (to 25-35 mph east of town) with gusts of 30-40 mph (45 mph east of town). The combination of wind and snow will continue to bring the risk of power outages.

Tonight, Tomorrow, and Monday: Skies will gradually clear overnight. With the deep fresh snow cover, temperatures will tumble into the mid teens downtown to around 10 in the colder suburbs. Wind chills will be near zero. Sunday and Monday will be dry with afternoon highs near 30 Sunday and 32-36 Monday, and lows Monday morning from 7-17 (suburbs-city).

Tuesday and Wednesday: Clouds increase Tuesday with another chance of snow or mixed precipitation in the afternoon lasting into Wednesday morning. Highs will be near 35 Tuesday, and near 30 Wednesday, with lows in the 20s Tuesday night. We'll have more details on this next possible wave of winter weather in updates later today and/or tomorrow.

(Next update to be between 5:30 and 6:00 a.m. Saturday)

High intensity snowfall has been pasting the metro area for hours now and will continue into tomorrow morning. The combination of the heavy, wet snow and wind is causing scattered power outages throughout the metro region. This storm is just over 1/3 of the way through and conditions will continue to deteriorate overnight. Snow will fall at a rate of 1-2" per hour for at least the next 6-8 hours, probably longer. Winds are likely to increase to around 20 mph, with gusts of 30-40 mph. Fortunately, as temperature continue falling, the consistency of the snow will become a little more powdery, so it will not adhere as well to trees and power lines later at night.

Throughout the region, snowfall totals so far are in the 6-12" range. Sleet has been reported primarily in Fredericksburg and points to the south. In the metro region, thunder has accompanied the snow in some cases and some additional thundersnow is possible in the next few hours.

Posted at 07:45 PM ET, 02/05/2010
The intensity of snow has continued to gradually increase this evening. Snowfall rates should at least persist at current levels if not increase. Rates of between 1-3" per hour are likely overnight. By morning (over the next twelve hours), most places in the metro region should pick up another 10-12 inches of snow, with locally higher amounts. Another 4-8" is possible during the day Saturday. We continue to expect total accumulations of 16-26". Temperatures are holding right around freezing which is making this a heavy, wet snow. Unfortunately, that may increase the risk of power outages as the night wears on (although temperatures should start dropping off some more after midnight), especially with winds increasing.

So far, most areas have picked up 3-6", with locally heavier amounts to the northwest and southwest of the immediate metro area. From Fredericksburg to Charlottesville, Va., there have been reports of sleet. Some sleet may advance northward and mix with snow in southern and eastern suburbs through around midnight, but the predominant precipitation type for the most of the metro region should be snow.
Posted at 06:00 PM ET, 02/ 5/2010
Blizzard warning expanded west to D.C

5:50 p.m.: The blizzard warning, earlier in effect for only the far eastern suburbs, has been extended west through the District.

Snowmageddon is here and it's just warming up. So far, the snow has been light to moderate as temperatures settle to and below freezing. Accumulations through now are on the order of a dusting to around 1-2" and road surfaces are begining to be affected as temperatures cool and the sun sets. The real deal arrives this evening and overnight, when snow could temporarily fall up to 2" or 3" per hour, rivaling the most intense rates this region ever witnesses. About as thrilling of a National Weatherperson Day as one could put together, right?


Periods of heavy snow are expected to enter the region around 7 p.m. (0z) and continue through much of the night. Through tonight: Get ready (if you stay up) for some of the heaviest -- if not the heaviest -- snowfall rates you ever see around here. It will come down in buckets, perhaps with some thunder, most of the night after things intensify markedly by 7 p.m. or so. The heaviest focus is likely from around 10 p.m. through sunrise. While most locations should pick up at least 1 foot overnight alone, don't be surprised if some spots pick up a good bit more. Lows drop to the mid-and-upper 20s as northeast winds blow around 20 mph, with higher gusts, leading to near-blizzard conditions.

Tomorrow (Saturday): If the huge amount of snow on the ground in the morning is not enough, no worries, because snow continues through much of the day Saturday. Snow will be most intense early but we should see a lighter and fluffier snow with some moderate to heavy periods lasting into the early evening. Additional accumulations of 4-8"+ are possible before it winds down. Highs rise to the upper 20s to around 30. Winds remain gusty from the northeast causnig blowing and drifting of snow.

Brief look ahead: As if we have not seen enough wintry weather lately, there's already another (much smaller) threat in the pipeline for late Tuesday into Wednesday. Right now it looks like it could threaten with just about every precipitation type depending on the ultimate track. In an already very snowy winter, it is certainly worth watching.

Posted by Ian Livingston | Permalink | Comments (315)
Share This: E-Mail | Technorati | Tag in Del.icio.us | Digg This

Posted at 02:15 PM ET, 02/ 5/2010

National Oceanic and Atmospheric Admistration (NOAA) Administrator Dr. Jane Lubchenco has released the following statement:

An epic snowstorm has the mid-Atlantic region in its cross hairs. At this time, personal safety must be first and foremost. National Weather Service forecasters have been tracking this storm for the past week and now that the storm is here it must be taken very seriously.
Chris Strong, Warning Coordination Meteorologist for the NOAA's National Weather Service (NWS) Office in Sterling, Va. just emailed CWG and other media outlets the following note:

Our media partners,

If you would, please ensure these points get some airtime. Tonight into Saturday morning will be about as dangerous as winter weather can get around here. Thank you.

Chris Strong
NWS Baltimore/Washington

IMPORTANT SAFETY TIPS FROM NWS

1. ENSURE PORTABLE GENERATORS ARE ADEQUATELY VENTILATED.

2. TRAVEL CONDITIONS TONIGHT ACROSS THE REGION WILL BE EXTREMELY DANGEROUS AND LIFE THREATENING. HELP YOUR LOCAL AND STATE GOVERNMENT FIRST RESPONDERS AND TRANSPORTATION AGENCIES BY STAYING OFF ROADS LATER THIS EVENING AND TONIGHT.

Keep reading for critical safety information...

Continue reading this post »

Posted at 01:45 PM ET, 02/ 5/2010
Weather Service: All-time snow record in jeopardy
*** Latest Capital Weather Gang Storm Update ***

The National Weather Service in Sterling, Va. has issued the following statement:

...RECORD SNOWFALL FORECAST IN THE BALTIMORE-WASHINGTON DC REGION...

...EXTREMELY DANGEROUS WINTER WEATHER CONDITIONS DEVELOPING TONIGHT...

GUSTY NORTHEAST WINDS 20 TO 30 MPH WITH VISIBILITIES FREQUENTLY FALLING BELOW ONE-QUARTER MILE DUE TO HEAVY SNOW WILL DEVELOP TONIGHT TO PRODUCE NEAR-BLIZZARD AND EXTREMELY HAZARDOUS WINTER WEATHER CONDITIONS TONIGHT THROUGH SATURDAY MORNING. TRAVEL IS HIGHLY DISCOURAGED TONIGHT AND WILL BE VERY DANGEROUS.

LOOKING BACK AT THE BIGGEST STORM OF RECORD FOR WASHINGTON DC... THE JANUARY 1922 KNICKERBOCKER STORM ... 28.0 INCHES OF SNOW WAS PRODUCED FROM 3.02 INCHES OF LIQUID WATER. CURRENT FORECASTS FOR THIS EVENT HAVE TOTAL LIQUID FALLING FROM THIS STORM APPROACHING 3 INCHES ... WHICH ACCORDINGLY WOULD CREATE A SNOWFALL THAT WILL RIVAL THE KNICKERBOCKER STORM TOTAL. GENERALLY ACROSS THE REGION ... 20 TO
30 INCHES OF SNOW WILL FALL BY SATURDAY EVENING

Posted at 11:00 AM ET, 02/ 5/2010
Snow underway: Some could see 2 feet or more
Worst of it is this evening into early tomorrow
The snow has started in many parts of the metro area, and as it becomes steadier and heavier, temperatures will drop and road conditions will go downhill. Treated roads should fare decently (not ideal, but probably passable) into mid-afternoon or so with temperatures near or a little above freezing. But as daylight wanes in the late afternoon, you'll want to get to where you plan to be for at least a couple of days.

Confidence remains high that most, if not all, metro area locations will get a minimum of around 16 inches by the time the storm finishes later in the day Saturday. There's a pretty good chance that some or many spots reach near or over 2 feet. For more, see our detailed forecast, which includes an accumulation forecast map, timeline, answers to FAQs and more.

One of the most difficult aspects during winter storms, for meteorologists and news organizations, is actually knowing what's happening on the ground, because radar only tells you so much. So help us out with comments below about the conditions where you are, and any other thoughts you have on what has a very good chance of becoming the second history-making storm this winter.

Posted at 11:00 AM ET, 02/ 5/2010
Eating our way through 'Snowmageddon'

While area grocery stores try to keep up with demand, some items are more popular than others. Now that Snowmageddon is here, the question remains: What do we all eat while stuck indoors over the next three days?

While some area residents have flocked to grocery stores to stand in line for yet a third time this week, others are relying on leftovers or dusty cans of non-perishables in the back shelves of their pantries -- that is, if there are any left after this season's storms.

Meanwhile, those who are hoping for area restaurants to stay open on Saturday may have a hard time finding one. Home-bound residents, such as the elderly and disabled, may have an especially tough time this weekend -- a good reminder for all of us to lend a hand during this storm.

Keep reading for some tasty Snowmageddon recipes. And see previous stories in Ann Posegate's "Wx and the City" series.

Posted at 09:40 AM ET, 02/ 5/2010
Today's Daily Digit

A somewhat subjective rating of the day's weather, on a scale of 0 to 10.

Though a thrill for snowlovers, this is a serious, potentially dangerous storm coming in.

Today: Snow/mix developing, changing to snow. 33-37. | Tonight: Heavy snow with high accumulations. 26-30. | Tomorrow: Snow, gradually ending late, breezy. 27-31.

SETTING THE SCENE

Not just major but most likely historic snow is approaching. Please take this potentially dangerous storm seriously. Snow will start between mid-morning and mid-day, slowly lowering the temperature to around freezing. Mixed precipitation may accompany the light, beginning period of the storm. Slowly through the afternoon and early evening the snow will accumulate. But the bulk of the storm's fury will come after dark when snow rates over an inch per hour are likely. Snowfall intensity will diminish Saturday afternoon, slowly. But breezes will pickup, creating cold wind-chilled air. The impact of this storm will be felt for long after snow ceases by Saturday evening.
9 AM to 1 PM FRIDAY
Snow develops SW to NE. Possible mix with rain/sleet. Temps 33-37.
1 PM to 7 PM FRIDAY
Snow, becoming heavy late. Some mix S&E. Temps 30-34.
7 PM to 1 AM SATURDAY
Snow, likely heavy. Some mix S&E. Temps 28-32.
1 AM to 7 AM SATURDAY
Snow, becoming breezy. Temps 26-30.
7 AM to 1 PM SATURDAY
Snow, decreasing some in coverage/intensity. Breezy. Temps 27-31.
1 PM to 7 PM SATURDAY
Snow tapering to flurries. Breezy. Temps 27-31.
Forecast Confidence: High

IMPACT FORECAST

How confident are you in your forecast?

It is virtually certain we will see copious amounts of winter precipitation from this storm. We are very confident the region will see double digit snow totals, even if some areas (primarily south and east of the beltway) mix with sleet and/or rain.

Could the storm "bust" or end up being much less than these hyped-up amounts?

We have not hyped the amount of accumulation we are predicting and have arrived at this forecast with careful consideration. Having said that, due to the complexity of the atmosphere and the major effects small changes in storm evolution can have, there is always the possibility that storm totals will be lower or higher than forecast. For this storm, however, we think the bust potential is relatively low given its size and consistency in computer model simulations.

Posted at 11:15 PM ET, 02/ 4/2010
Update: Some FAQs for Snowmageddon Eve
Potentially historic snowstorm still on track
* Winter Storm Warning Friday morning through Saturday evening *
* Bob Ryan to WJLA to team up with Doug Hill? *
* Will the storm make history? | Q&A transcript | Winter driving tips *
* Follow storm on twitter: #Snowpocalypse | E-mail forecast to a friend *
* News, traffic & storm coverage: Local home page | Get There *

A few tweaks to our accumulation forecast for areas to the south, and just a slight change to our estimated start time for the metro area (between 8 a.m. and noon tomorrow, instead of 9 a.m. and 1 p.m.). Other than that, all is on track for a storm that could make a run at history. Check out the CWG team's accumulation map and timeline below, and below that answers to a few questions you might have. Then, get some sleep, and stay with us tomorrow and through the weekend for the latest storm information.
8 AM to 12 PM FRIDAY
Snow develops SW to NE. Possible mix with rain/sleet. Temps 33-37.
12 PM to 7 PM FRIDAY
Snow, becoming heavy late. Some mix S&E. Temps 30-34.
7 PM to 1 AM SATURDAY
Snow, possibly heavy. Some mix S&E. Temps 28-32.
1 AM to 7 AM SATURDAY
Snow, becoming breezy. Temps 26-30.
7 AM to 1 PM SATURDAY
Snow, decreasing some in coverage/intensity. Breezy. Temps 27-31.
1 PM to 7 PM SATURDAY
Snow tapering to flurries. Breezy. Temps 27-31.
Forecast Confidence: High

STORM FAQs

Is this really happening again? Incredibly, yes. What are the odds of two double-digit snows in the same season? Funny you should ask. We have an answer here.

When will it start? Start time is often tricky for snowstorms, because it's hard to judge how slowly or quickly the lower atmosphere will become moist enough to allow falling snow to start reaching the ground, rather than evaporating into air that is too dry. Based on the latest data, our best estimate is that snow will develop across the metro area from southwest to northeast between 9 a.m. and noon. Snow may be mixed with some sleet or rain at the onset.

See our earlier post (which is still valid) for impact forecasts and the detailed forecast into next week.

When will travel get really bad? We're thinking that snow will be primarily light to moderate through the afternoon, with accumulations on the order of a few inches, as opposed to the moderate to heavy snow that's likely tomorrow evening and overnight. So with temperatures expected to be near or even a little above freezing for much of the day, roads may not be too bad until we get into the late afternoon and early evening. Still, you'll want to drive with caution and be especially careful on surfaces that tend to ice over the fastest -- bridges, ramps and overapasses.

Are power outages a concern? Yes. While this snow may not be as wet as the very wet snow we saw Tuesday night, it may well be wetter than the snow that fell during the December storm. The heavier snow combined with winds gusting in the 30-40 mph range tomorrow night and Saturday could bring down trees and power lines.

When's your next update? We'll be back at 5 a.m. with the latest forecast and answers to more FAQs.

Posted by Dan Stillman | Permalink | Comments (62)