"Y'all Ready For This?"

"Y'all Ready For This?"
By 2 Unlimited, 1991 single and Space Jam Soundtrack

11:20 AM EST 2/11 (UPDATE from 5:25 AM - Winter Stormcast Team) If this next storm unfolds as currently projected, we might end up in a real life "SPACE JAM" like we were in February 2010. Details below and a storm timeline map posted later today. 

SYNOPSIS: 
With 48 hours remaining before a potentially classic "Nor’easter" winter storm is set to impact the region Wednesday night into Thursday, we will begin narrowing our scenarios from the previous post. A storm system from the west will become enhanced by moisture from the Gulf of Mexico. Then the low pressure will track northeastward along the coast. This track is not set in stone, and there is still uncertainty regarding the precise path, the amount of precipitation and to what extent liquid-to-snow ratios will be.

LEFT: Latest precipitation projections show 1.0-2.5 inches of liquid stretch from Louisiana to Maine for the period Tue 2/11 to Sun 2/16, suggesting a possible subtropical moisture feed (known as an "atmospheric river") may be a factor this storm's outcome.

TIMING: For the Mid-Atlantic, start time is expected by Wednesday evening, from south to north. For areas along the I-81 Corridor in Virginia, snow will get underway in daylight hours on Wednesday, and in the Southeast impact are expected Tuesday night.  The storm is expect to depart the coast starting Thursday afternoon. 

PRECIP TYPE: Snow is expected for much of the Mid-Atlantic west of Chesapeake Bay and along the I-95 corridor into Virginia and North Carolina. Precipitation for all these areas could be quite heavy at times Wednesday night into Thursday morning. This projection is a more specific and detailed version of yesterday’s Scenario B, but shifted slightly west as shown on our enclosed map. 

• With a storm track right along the coast, we are currently thinking that those west of I-95 will see snow as the predominant precipitation type. 
• Along and east of I-95, we may have some mixed precipitation to deal with, since there is the possibility the storm pushes in warmer air Thursday morning and flips us over to sleet or rain, before going back to snow at the end. 

ACCUMULATION: Based on latest moisture projections from the NOAA Weather Prediction Center and the North America Mesoscale model output for BWI airport as a representative location, and analysis of latest US and other computer models:

• Liquid for this storm reaches or exceeds 1.0" for much of Maryland, eastern Virginia, the Delmarva, SE Pennsylvania and New Jersey. 
• With possible liquid-to-snow ratios of 12:1 along and west of I-95, 15:1 for extreme northern MD into southern PA, and lower ratios of 10:1 or less in coastal areas near or along the Atlantic, this storm has the potential to drop well over 8"+ in some areas. 
• Locations that remain all snow if no mixing of sleet occurs may top 12" or more. 
• For specific meteorological details on snowfall ideas, you can review the NOAA WPC Heavy Snow Discussion 

IMPACTS: It is critical to note that regardless of precipitation type, wind will be a major factor in this storm. By Thursday morning into the evening, winds may gust near or above 25 mph. If sleet and/or freezing rain are involved in, this combination of heavy wet snow and gusty winds may lead to a new round of significant power outages in areas affected. We urge residents to avoid thinking that "because the storm is changing over the sleet or rain, it must be WEAKENING!" That is NOT true. In fact, you may be at GREATER DANGER if you venture out in those conditions than just all snow.

TEMPS: For much of the Mid-Atlantic, the storm will have a cold start. That is why we think the region will start as all snow. However, the storm does not have access to a feed of Arctic air, so temperatures my actually warm through the event. This  raises the possibility for precipitation to start mixing with sleet in the late AM hours of Thursday.

BUST POTENTIAL  Although this storm is, regarding a spatial scale, one of the largest potential events since 2010, uncertainty in the track could change the outcome drastically like what occurred in the December 25-26, 2010 coastal snowstorm. What first looked like a Christmas Day 6-12" storm in the DC/Baltimore region turned out to be flurries, and Ocean City MD received a surprise 14" of snow.

So with that said, there is always bust potential with any storm forecast:

• Bust Plan A - (25% Chance): The storm track shifts west of model guidance, and pushes warmer uttemperatures into the I-95 corridor. Thus a longer period of mixed precipitation or even rain could be expected. And the NW suburbs may not even stay as all snow. The axis of heaviest snow would be shifted slightly westward as well. 

• Bust Plan B – (15% Chance): The storm track shifts east of model guidance. This would bring snow all the way to the coast, but start to cut down on liquid precipitation for the NW suburbs. This would mean no mixing issues, but less precipitation altogether. 

Stay with us through the day for more information as it becomes available, including a preliminary snowfall later today. For now, if you love snow, we hope "y'all are ready for this."

(Forecasters Mike N., Mintong N., Connor M., Julian B., Greg J., Nikki B., Andrew B., and Advisors R. Foot, K. Krichinsky, B. Lear, Dr. Pete W.)