3:00 PM | *Wednesday looks like another day with a combination of snow, ice and rain with possible snow accumulations on the front end in areas north of the PA/MD border*

12Z NAM (3-km) forecast map for 7am on Wednesday; map courtesy NOAA/EMC, tropicaltidbits.com

Overview
Super Bowl Sunday featured a combination of snow, ice and rain and we may have something somewhat similar to this on Wednesday, but in this case there may be a bit more snow on the front end in areas north of the PA/MD border.  Low pressure will move southwest-to-northeast during the day and frozen precipitation is possible at the front end of this event and can’t be ruled out on the back end as well with plain rain likely in between.

12Z NAM (3-km) forecast map for 10am on Wednesday; map courtesy NOAA/EMC, tropicaltidbits.com

Details
Low pressure is likely to slide from southwest-to-northeast on Wednesday just to the northwest of the big cities and when precipitation arrives there will be cold air in place.  While a wintry mix if possible at the onset in the DC metro region, snow is likely to begin this mid-week event in the Philly, NYC metro regions; especially, in the northern and western suburbs. In fact, an inch or two of accumulation is possible Wednesday morning in the Philly metro region before any changeover and perhaps 2 to 4 inches in and around NYC.  After the initial period of a wintry mix in DC and snow in Philly and NYC, milder air will try to push in from the ocean and precipitation may change to all rain later in the day, but the erosion of the cold air will be more difficult this time compared to Sunday when we had strong southerly winds at low-levels of the atmosphere.  

12Z NAM (3-km) forecast map for 1 pm on Wednesday; map courtesy NOAA/EMC, tropicaltidbits.com

Any shift in the storm track over the next 36 hours or so would have an impact on precipitation type in the immediate I-95 corridor and we’ll closely monitor this possibility.  Higher elevation locations in interior sections of PA may very well receive 6+ inches from this mid-week storm (e.g., NE PA, central PA). The 12Z high-resolution version of the NAM model depicts snow (blue) or ice (pink, purple) at the onset of the Wednesday event with rain (green) for later in the day.

Meteorologist Paul Dorian
Vencore, Inc.
vencoreweather.com