Best of times, worst of times

"It was the best of times, it was the worst of times."

- Charles Dickens, Tale of Two Cities

• COASTAL LOW FORMATION ABOUT 6 HOURS LATER THAN EXPECTED DELAYS ARRIVAL OF SNOW IN MID-ATLANTIC. 
• COLD AIR PRESSING SOUTH INTO EASTERLY FLOW REACTIVATED SNOW ACROSS MARYLAND, DELAWARE AS ENERGY WORKS NORTH WHILE CAROLINA LOW FORMS.
• HEAVIER BANDS EXPECTED TO FORM OVER DELMARVA AND I-95 CORRIDOR AFTER 6 PM AS COASTAL HUGS DELAWARE AND JERSEY COAST TONIGHT. 

10:15 AM 1/26 - UPDATE FROM THE WINTER STORMCAST TEAM

1) Easterly flow has established across the southern Mid-Atlantic while the front that was stalled earlier in central PA moved south past 12 hours. National Weather Service has extended advisories in MD and VA southward to account for likelihood of wintry precipitation impacting area farther south than first expected. 

2) The enclosed surface streamline map shows easterly flow has setup across almost the entire state. This is bringing moist Atlantic air west across Delmarva and over the Bay into the western shore. This is also evidenced on your local radar with snow filling in east to west.

3) With the coastal taking a while to get underway, this easterly flow in place, and energy transfer slow from the primary lows in Virginia, we expect a light steady snow to be the rule of the day for much of the state. Roads may stay wet in eastern counties, but could become snow covered in western counties as they are in the colder sector to the north of the Low.


THE KEY FACTOR TODAY: Sun angle. Those experiencing snow will see it continue at present intensity for another 5-6 hours. 

• Toward early afternoon it may actually decrease some. Then as the coastal Low picks up in speed and intensity, Sun angle will be dropping toward evening. 
• After 3 PM, in a surprisingly magical way, snow will suddenly start to whiten the ground everywhere. 
• We have seen this many times before, and with plenty of Atlantic moisture to work with, there's probably no way out of a snowy, but somewhat manageable day, in Maryland.

TONIGHT AND TOMORROW? We don't like to say "It's up in the air" but honestly, it still is. Since so many computer models have led forecasts astray, we are leaning more on a nowcasting and upper level analysis approach with only very short range model data in small time increments. 

The first image is a projection for Precipitation Type at 9 PM Tonight from the North American Mesocale. This suggests snow continues in the I-95 corridor but changing to rain in the Eastern shore and southern Maryland.

The second image below is the "broadbrush" Precipitation forecast from the NOAA Weather Prediction Center for 7 PM tonight, this shows a more widespread and much snowier solution for a large part of the Mid-Atlantic, with snow likely in many areas.

So the game is a-foot. It will be interesting to see how things stack up. We welcome your take on the situation. It's a nowcast event plain and simple.

Forecasters Foot, Connor M., Joe F., Jolene W., Jason M., Advisors Pete W. and Keith K. 

SIGNIFICANT WINTER STORM TO IMPACT EASTERN MID-ATLANTIC 
AND NORTHEAST SUNDAY NIGHT INTO TUESDAY

• BLIZZARD WARNINGS FROM CENTRAL JERSEY TO NYC TO BOSTON, ACCUMULATIONS  20" OR MORE POSSIBLE. 

• DC - BALTIMORE METRO REGION TO SEE DOUBLE ROUND OF SNOW, FIRST FROM CLIPPER, THEN SECOND ROUND MONDAY NIGHT INTO TUE AM.  WINDS MONDAY NIGHT MAY GUST NEAR 40 MPH CREATING WHITEOUT CONDITIONS.

6:00 PM 1/25 - WINTER STORMCAST TEAM STATEMENT 

ABOVE: CURRENT NWS ADVISORY STATEMENTS FOR NORTHEAST U.S.

SYNOPSIS A highly fluid and rapidly changing forecast situation over the next 24-48 hours is going to require (or test) a high level of patience across the Northeastern U.S. At issue is an eastward traveling clipper moving along a the southern periphery of a large Arctic High pressure system. As you can see from the NOAA Surface Projection for Monday morning, this large scale dynamic will create widespread easterly flow of moist Atlantic air into the much colder Arctic air being pressed southward.

SITUATION Starting later this evening into Monday morning, this storm will first produce round of heavy snow in western and central Maryland, the West Virginia panhandle and southern PA. This first period of snow from the clipper is likely to produce 4-8" in western areas, and 2-4" near metro areas by dawn. 

* By Monday night, bands of snow should begin to fill back in over the I-95 corridor and the Eastern shore at first. An additional 3-6" is possible in counties on west side of the Chesapeake Bay, while the Philly metro region and the Upper Eastern Shore gets clocked with 6-12". 

In the event the storm slows and stalls near the Jersey coast, accumulations could be significantly higher, depending on the track of the storm.

Were that to occur, all forecasts will have to be completely revised. We seek not to over-amplify the situation, but to highlight the significant uncertainty inherent in a rapidly evolving winter storm that will cover a geographic spread larger than most hurricanes. 

COMPARISON The most basic comparison we can make to a setup resembling this could be February 17, 2003. A southern stream system overran a cold High pressure dome. What started out as snowfall projections of 3-6" early in the event ended around 18-24" as the easterly flow, southern energy and moist air all collided over the northeast. 

While this situation is much different in terms of moisture source, the fact that a High pressure looks to bleed out into the Atlantic and stall the storm somewhat may have prompted Blizzard Watches and Warnings along the Mid-Atlantic coast. That is a troubling similarity between this event and the February 2003 and February 10-11, 2010 storms.

So if you are an Emergency Manager or Facilities Operator, it looks to be the worst of times, but for Powderhounds... well, no argument there. They'll be in powder heaven celebrating the best of times. And just think, February is not even here yet! 

ROUNDUP Since this multi-day complex winter storm will have wide ranging impacts across numerous states, and many of our readers, we have assembled this listing of forecast zones from our Mid-Atlantic Team, with an enclosed link for your reference.

• MID-ATLANTIC WINTER STORMCAST PAGE
• NORTHERN WEST VIRGINIA (facebook.com/ffnorthernwestvirginia)
• WESTERN MD (Potomac Ridge & Valley ) 
• CENTRAL MD (facebook.com/ffcentralmaryland) 
• CAPITAL REGION (facebook.com/ffcapitalregion)
• SOUTHERN MD (facebook.com/ffsouthernmaryland)
• NORTHEAST MD (facebook.com/ffnorthernbayshore)
• LOWER EASTERN SHORE (facebook.com/ffbayshore)
• SURF 'N' SAIL (OCEAN CITY, MD) (facebook.com/ffsurfsailmidatlantic)
• CENTRAL NEW JERSEY (facebook.com/ffcentralnewjersey)
• METRO NEW YORK CITY (facebook.com/ffmetronewyork)

DISCLAIMER: Please always remember to consult official statements at your local NWS forecast office, and be advised that information we post here is for educational purposes only. Decisions by local governments are made following the latest official guidance provided by the National Weather Service and the NOAA Weather Prediction Center, as well as State Emergency Management Agencies

BELOW: PROJECTED SURFACE MAP FOR 7 AM MONDAY 1/26

BELOW: LIQUID PROJECTIONS FOR MONDAY THROUGH THURSDAY