An area of low pressure will move out of the lower Mississippi Valley on Tuesday toward the spine of the Appalachians, meanwhile a coastal storm is forecast to develop off of the Mid-Atlantic coastline on Wednesday. The ensemble forecast models are showing an increasing threat of a high-impact winter storm for portions of the Mid-Atlantic on Wednesday.
The image below (courtesy WxBell) shows the latest European Ensemble model and depicts quite a spread in placement of the coastal storm on Wednesday of next week. Notice some of the red “Ls” on the map below are located near Hatteras, NC while others are located just off of the Delmarva coast. The exact track will be key regarding how much cold air locks in across the populated 95 corridor from Fredericksburg to Washington and Baltimore.
Model accuracy will begin to increase once the upper level energy that will be responsible for the development of the surface lows actually makes landfall across the west coast of the United States on Monday morning. There are not enough ocean buoys recording current weather data that the models rely upon for an accurate forecast (garbage in = garbage out). If your mathematical equation has inaccurate input data, the output, or solution will be inaccurate.
In the image below, notice the bright red “U” shape centered over Nevada on Monday morning. This is the upper level spin (piece of energy) that will move eastward on Tuesday, eventually igniting the development of a coastal storm on Wednesday. On Monday morning I believe we will start to see the ensemble models come into agreement on the exact track of the coastal low.
Below are the latest European, Canadian (GEM), and American (GEFS) Ensemble models showing potential snowfall accumulation with this upcoming storm (images courtesy WxBell).
European Ensembles: Potential snowfall accumulation through Wednesday
The 50 images below (labeled 01-50) in the upper right hand corner shows a high-impact snow for portions of the Mid-Atlantic and southern New England. Note that not all are in agreement on how much snow falls across the interstate 95 corridor for reasons discussed above.
GFS Ensembles: Potential snowfall accumulation through Wednesday
Canadian Ensembles: Potential snowfall accumulation through Wednesday
I will provide additional updates as the ensemble models continue to zero in on a solution for the Washington Area, Stay Tuned.