Wednesday, December 7, 2011

Fast and furious


5:00 AM EST 12/7/11 | The coastal bomb, currently at 989 millibars, has raced northeast to the Massachusetts coast and will leave behind clear skies and windy conditions today.  If you have experienced snow, flooding or wind damages this rapid fire event, please report yourobservations and location in the comments.




Here is a science tidbit for Meteorology fans and science teachers, who, like sports fans, love statistics: This storm will more than qualify as the classic "atmospheric bomb." As Forecaster Jason first noted, the pressure fall from this storm over an 18-hour period from noon Wednesday to 7 AM Thursday will end up near 40 millibars! HPC projects the storm to reach 964 mb within a few hours, per HPC:




Maryland Madness, 
Virginia's Vengeance
6:50 PM EST 12/7/11 | While Maryland has Winter Storm Warnings all the way over to Severe Thunderstorm Watches, Virginia has ramped up to Severe Thunderstorm Warnings. Forecast details in facebook for the Bayshore and Tidewater Zones, as well Central Maryland

The image below shows Winter Storm Warnings in western MD (pink), Flood Warnings for the I-81 and southern I-95 corridors, and Severe Thunderstorm Warnings (orange) for southern Virginia with Winter Weather Advisories in between (purple). Latest advisories from the Baltimore/Washington NWS.




FOR MARYLAND READERS: Reports and updates for the I-95 corridor are posted in a "web filter-friendly" link to our Central Maryland page


FOR PENNSYLVANIA READERS: Latest reports are in our facebook pages for Southeast PA and Central PA. 


FOR VIRGINIA READERS: If you are able to appropriately access facebook, our latest update for Northern VA (Forecaster Kurt) and Central VA (Forecaster Nikki) are posted.

Here we go again
WINTER WEATHER ADVISORIES, WATCHES AND WARNINGS NOW STRETCH FROM EAST TENNESSE TO MAINE. FLOOD WATCHES FOR CONNECTICUT, RHODE ISLAND AND EASTERN MASS.
Current NWS advisories for Mid-Atlantic & Northeast
Coastal "Bomb" may develop Wednesday night off the Virginia Capes, to rival Hurricane Irene* in central pressure; Winter Storm Watches and Warnings from North Carolina to Maine, up to 10 inches expected in the Appalachian mountains. More on the atmospheric "bomb" below...




11:40 AM EST 12/7/11 
INCREASING SEVERE WEATHER RISK | The southern Chesapeake Bay and portions of the Delmarva peninsula may see a period of thunderstorm wind gusts near 50 mph from 4 PM to 8 PM today. The NOAA Storm Prediction Center has outlooked this area for a slight risk of tornadoes as shown in the enclosed graphic. Our latest reports for this area posted in facebook for the Virginia Tidewater and the Bayshore of Southeast MD.




*The Hurricane Irene comparison? On August 26, 2011 Irene reached a central pressure of 942 millibars. Since Tuesday, computer models have shown that this storm will rapidly deepen in the overnight hours. The anticipated drop in central pressure is projected to be over 24 millibars in a 24 hour period. This is the unofficial criteria for an "atmospheric bomb" or "bombogenesis" which is a meteorological slang along the eastern seaboard. The October 2011 Northeast U.S. snowstorm is the most recent example of this phenomena.

‎7:45 AM EST 12/7/11
MID-ATLANTIC STORM UPDATE Overnight, computer models and forecasters alike came to a consensus that the influence of powerful upper level low is going to fire off a rapidly deepening coastal "bomb" at the surface. By tonight, an explosively developing storm along the Virginia Capes will begin to move northeastward. As a result, areas up to 200 miles west of the storm may be impacted by "dynamical cooling" which will be responsible for generating snow in this early season event, even into the major metro areas of Baltimore and Washington as well as much of the Central Appalachians by tonight.

Evidence of the National Weather Service's concern for this potential are the surprisingly widespread Winter Weather Advisories, Watches and now even Warnings from North Carolina to Maine. Current advisories 


TIMING & IMPACTS Precipitation has already entered over most of the region with rain possibly heavy at times today. A change over to snow is expected from west to east across the region tonight, beginning around 3 pm in the central Appalachians. Rain in the I-81 corridor is expected to change over to snow around 8 pm and progressing north and east through the overnight hours. 

The 95 corridor and adjacent counties in Maryland may start to see snowflakes after 1 am then a brief period of snow is possible over I-95 from Wilmington, DE to NYC. Precipitation is expected to depart from southwest to northeast starting near 3 am in central MD, with the back end of precipitation departing the interior Mid-Atlantic by mid morning and coastal areas by noon. 


IMPACTS TO 95 CORRIDOR (SOUTHEAST PA -- DC METRO): 

Influence of heavy rainfall prior and lack of substantially cold air drives our low projections for the I-95 corridor. For the most part, right along I-95 and to the south and east, we expect a coating to an inch. To the north and west of I-95, accumulations will likely remain from 1-2 inches. Once you get north and west of northern VA, Frederick, MD, Westminster, MD, and Lancaster, PA, accumulations are expected to range from 2-4 inches. 



IMPACTS TO 81 CORRIDOR (CENTRAL PA -- CENTRAL VA) : 

The I-81 corridor and just to the north is expected to receive some accumulating snow, likely 2-4 inches with some isolated spots to 6 inches from northern VA through Hagerstown, MD, Harrisburg, PA. North of Harrisburg, the region may see a general 3-6 inches, but higher elevations could see accumulations of approaching 10 inches. Other than that, highest amounts are expected in the mountains of West Virginia, northern Virginia, and western Maryland with a general 3-6 inches expected in that area along with isolated amounts of up to 8 inches. 

SHARE YOUR WEATHER WITH US...We encourage all readers to post their photos of the storm throughout the event in our comments section or on any of our regional/local facebook pages. Updates will continue throughout the day.


(Forecasters Natoli, Meehan, Foot and the Winter Stormcast Team) 

17 comments:

hocoKtchr said...

Rain, rain go away! Some snow would be so so so much better!  Even a little.... C'mon man!!!!  :-D

Amy said...

I would be thrilled with a two hour delay!  Just a little sleep in time before we hit the books again.

hocoKtchr said...

Amen to that!!!!! 

ravensbbr said...

Coldest rain I can remember, almost feels like slushballs, but not quite...

Julie Ray Smith said...

can I get a flake? just a flake. FAITH IN THE FLAKES

ravensbbr said...

<span>OK, so the fact that Andy hasn't weighed in on this...whatever it is precip system means one of two things.  
 
He's either dead, or there's no snow coming. Thinking it's the latter...</span> :-P

Andy, Southern York County, PA said...

I actually had to work late tonight :( to compensate for the 4 hour lunches I usually take.  Moderate snow falling here and 33 degrees.  Slushy dusting on cars and garden.  I think the higher elevations around northern Carroll and Baltimore sqeek out 1-2 inches.  Anything further south will be hard to get much of anything to stick as the storm is moving way too fast.  Ground truth will tell!

Andy, Southern York County, PA said...

Taken 10 minutes ago, snowing very heavy now. 

Andy, Southern York County, PA said...

Oh, well.  Some snow is better than none. 

Andy, Southern York County, PA said...

Not dead, just frozen, so I can be reanimated and share my thoughts during the next ice age!

ravensbbr said...

yeah, just a dusting here, snow rate and flake size is incredible, but not much sticking. It's a step in the right direction...

Julie Ray Smith said...

where is Rufus?

Andy, Southern York County, PA said...

Waiting patiently for the period from 12/14-12/20 ;)

ravensbbr said...

Here here!

Andy, Southern York County PA said...

http://www.accuweather.com/en/weather-news/a-stormy-week-before-christmas/58851

HMM....... it seems that others are liking 12/14-12/20..... Wonder why?

Jason Mitchell said...

Hmm. My thinking (and the rest of the FF Winter Stormcast team) is that Dec 21-31 would be the next real shot for snow chances. I just don't think there will be enough cold air in place with the next two systems. Hopefully I'm wrong though.

ravensbbr said...

Track still look favorable to you on this one? Looks to me to be a skosh too far west for us, not sure yet though obviously.