Sunday, February 6, 2011

Winter Stormcast Zone | Mid-Atlantic

Lead Forecasters: Jason M. and Connor M.

9:25 PM Monday 2/21/2011 - SYNOPSIS: A storm system from the Midwest is spreading a swath of precipitation into the region. A low pressure system is rapidly intensifying off the Mid-Atlantic coast and precipitation is transitioning to sleet, then to snow overnight. Winter Storm Warnings have been posted for much of Maryland, the West Virginia panhandle, Northern Virginia, Central Portions of the Laurel Highlands in western PA, Southern Pennsylvania, parts of Delaware and New Jersey.

AMOUNTS: At this time we are forecasting a general 5-7" inches of snow for areas around Baltimore, with 3-5" towards the Washington, D.C. area. Western Maryland and the west Virginia panhandle is targeted for 5 or more inches, with around 3-5" for northern Virginia. Delaware and eastern Maryland will also get snowfall, with an average of 2-3" in the Southern DelMarVa to 5"+ in the Northern zones. There is a possibility of wrap-around banding to deliver an additional inch or two as the storm pulls aways. Updates for this region posted in our Bayshore zone by Forecaster Mike N.

TIMING AND IMPACTS: Rain transitions to snow after sunset, and will continue with brief periods of heavy snow at times overnight. As a low pressure system redevelops near the Virginia capes, and draws in colder air combined with very warm surface temperatures near the center, the system may intensify rapidly. This could produce snowfall rates of 1-2" per hour, not unlike what happened in the Baltimore-Washington areas on January 26 during the "torrential snowfall" event forecasted by our team.

Snow will end by the mid morning hours Tuesday as the intensifying Low pressure system pulls away. Strong gusty northwest winds in the storm's wake will knock Tuesday night temperatures into the teens most of Pennsylvania and West Virginia, northern Virginia and Maryland west of the Chesapeake Bay.

EFFECT ON TRAVEL These unseasonably cold temperatures will quickly refreeze remaining snow and sleet on untreated road surfaces, bridges and overpasses. We strongly expect significant travel delays Wednesday morning in addition to problems on Tuesday.

(Author: Forecaster Jason. Collaborators: Forecasters Winterman, Connor, Advisors Winstead, Lear, and Foot)

10:15 PM 2/19/2011

Team Statement: After a tremendously windy start to the weekend, we are watching the potential for some snow Mid Atlantic Monday night into Tuesday morning. A low will track from the Midwest to the Mid Atlantic coast bringing snow into the area, but accumulations will depend on how quickly a transition from rain to snow occurs, and how much precipitation is expected to fall. Winter Weather Advisories are posted from northern Ohio to northern Pennsylvania and southern New York.

(Authors: Forecasters Jason and Connor. Collaborators: Forecasters Mike N., Dakota S., Winterman)

7:25 AM Sat 2/19/2011 TEAM STATEMENT: A whippingly windy Saturday to all! It is hard to believe we are talking winter weather in the near future after high temperatures in the Mid-Atlantic reached the 60's and 70’s yesterday. However, a storm system now arriving in California will be making its way towards us by Monday night into Tuesday. Timing and impacts still bring many questions, but we do believe most of the Mid-Atlantic above I-70 has a good chance of seeing some accumulating snow by Tuesday morning. An overview of ideas is posted in the Climate Prediction Center's U.S. Hazards Assessment

One scenario shown by some computer models has precipitation beginning as rain Monday evening, before before transitioning to moderate snow after midnight and departing by daybreak or shortly after. However if the storm does in fact not arrive until overnight into Tuesday, the ground may have cooled sufficiently to permit a mostly snow event as well as accumulation. At this time it is too early to project any amounts, but we will try our best to solve this storm as always! Additional details will be posted each day as the event nears.
Image: Projected liquid amounts for the period Saturday-Monday by the NOAA Hydrometeorological Prediction Center. Note: Majority of this precip in the Mid-Atlantic not expected until Monday evening at the earliest. -(Author: Forecaster Winterman; Contributing: Forecasters Mintong N., Jason M., Connor M., Michael N., Editor: R. Foot)


10:30 PM Sunday 2/6/2011 The next weather system will move across the Mid-Atlantic late Monday into Tuesday. Light rain Monday night may mix with or possibly changeover to snow. Any snowfall accumulation will be minor across the region. Low pressure along the Gulf coast Wednesday is expected to push off the Atlantic Southeast coast, with an area of wintry precipitation across portions of the Carolinas. There is uncertainty regarding whether the system will move steadily eastward off the coast or move northward along the coast.

SCENARIO A: The storm remains weak while moving off the Carolina coast and out to sea, with northward extent of precipitation remaining below the Washington, D.C. and Baltimore metro areas. Significant snowfall accumulations would occur in southern and southeastern Virginia as well as the Carolinas. Precipitation amounts would be higher the farther south your location, as shown on the HPC precipitation map.

SCENARIO B: The system in the southern branch of the jet stream interacts with upper level energy from the northern jet stream, resulting in significant intensification of the low and a track up the Mid-Atlantic coast. In this scenario moderate to heavy snow would be confined to areas east of I-95, with snowfall spreading into the Northeast.

At this time the team believes scenario A will most likely verify, sparing the Mid Atlantic and Northeast of significant impacts. Please stay tuned for future updates regarding this potential storm.

(Forecaster Jason. Collaborators: Forecasters Winterman, Connor, Advisor Lear)


Andy, Southern York County PA (FORECAST ADVISOR) said...

Accuweather tends to hype too often in my opinion.  I do read many perspectives on storms and patterns from "well known" mets, amateurs, blogs, and the NWS etc.  I actually like the ideas that Henry M. has presented in this little writeup here, and they reflect what I think for the most part.  Well, I actually hate the ideas, but they do reflect what the best data is showing.

ravensbbr said...

TO: Whoever is operating the anti-snow force field for the Mid-Atlantic.
FROM: MD & PA Powderhounds
RE: Same

Dear Sir or Madam,

Under penalty of the wrath of many, many powderhounds, you are hereby directed to remove the aforementioned ASD (Anti-Snow Device) that is causing these storms to retrack everywhere else but MD & PA. You must have been asleep and forgot to turn it on for the one good storm we had, but that is not an excuse.

Consider this your only warning, or more drastic action will have to be taken.



Powderhound Society of Central Maryland and Pennsylvania

BioPat said...

I tend to agree Andy.  The days are getting longer providing the necessary sunlight to warm the ground significantly on these more moderate temperature days.  I know we're headed for a cold blast lasting the next few days, but the further we progress into February, I do think our chance of another major snow decreases.  I know we have had heavy March snows, but this is just not the year, with the La Ninia still in control.  I do think we stand the chance for some icing before it's over, but so goes the winter. 

Rufus79 said...


Willaim Earley said...

@ PSOMCS&PA...Go west young ones ...Go west!