Monday Update on Wednesday’s Winter Storm

The forecast models continue to disagree on the exact track of the coastal storm and how quickly it strengthens. For those of you who wanted all snow in the immediate Metro Area, the models have trended toward a more inland track bringing the rain/snow line right into the 95 corridor. There is still time for models to adjust the track further east and any shift  eastward even by 25 miles would have a significant impact on how much snow, sleet and freezing rain falls in your neighborhood. For those of you in southern Maryland this is looking like mainly a rain event.

The latest North American Model (NAM)

The NAM model (image below courtesy Tropical Tidbits) tracks the storm system from near Raleigh, NC toward the NJ coastline and depicts a mix on Wednesday changing over to rain with little to no snowfall accumulations across the interstate 95 corridor. 

If the above track verifies, there would be little to no snowfall accumulation across the 95 corridor!

The Global Forecast System (next image, courtesy Tropical Tidbits) has been the most bullish for a significant accumulating snow in DC because it keeps the track of this storm system off of the NC coastline before it moves northeast and eventually out to sea. 

If the GFS track verifies, there would be significant snowfall accumulation in DC and crippling accumulations across  northern Maryland and along/east of the Blue Ridge in northern Virginia. Southern Maryland and Fredericksburg would receive very little/no snow in this scenario.

The European Model (image below courtesy WxBell) has also trended west in track and brings rain into DC on Wednesday evening and sleet and freezing rain all the way to the Blue Ridge before precipitation changes back to snow before ending. 

If the European model track verifies, there would be a very tight snowfall gradient sitting right over the US-29 (Virginia) and 95 corridor (Maryland). Even the snow totals below would be cut down due to sleet/freezing rain mixing in along/east of the Blue Ridge.

The Canadian model (image below, courtesy WxBell) also brings the storm system inland and produces more of a crippling sleet and freezing rain event from the Blue Ridge mountains eastward to interstate 95 with snow being the predominant precipitation type across the Shenandoah Valley, Panhandle of WV, and along/north of the Mason Dixon line.  An Ice Storm is not what any of us wants as there would be gusty winds bringing down trees/power lines.

Canadian model showing the bulls-eye of snow from western Loudoun County to the western suburbs of Philadelphia and NYC.

Canadian model (image below courtesy WxBell) showing very heavy sleet accumulations in DC including in the northern and western suburbs. This amount of sleet would shut things down on Wednesday for sure. 

 The image below (courtesy WxBell) is from the Canadian model showing over a half-inch of ice accretion (from freezing rain) accumulating across the interstate 95 corridor. Sleet is frozen rain droplets that bounce when they hit a surface. Freezing rain is liquid rain falling to the ground and freezing on surfaces that are at or below 32 degrees. 

So there you have it, now you know just how difficult it is to forecast the weather when the forecast models do not agree on an exact track.

The odds are increasing that DC and its northern and western suburbs will receive more of a wintry mess with snow to start, then changing over to sleet and freezing rain.  The District may even go over to plain rain if temperatures rise above freezing as many of the latest models are suggesting.  

The northern Shenandoah Valley, WV Panhandle, northern Fauquier and western Loudoun counties and northern Maryland have the best probability of receiving crippling snowfall totals (8″ or more) with this storm system.