12:00 PM | **Some snow tomorrow morning in the DC-to-Philly-to-NYC corridor with the arrival of the next Arctic air mass…very cold conditions tomorrow night and Friday**
Paul Dorian
“Post-frontal” snow will be possible tomorrow partly as the result of a strong upper-level jet streak that will produce upward motion in the Mid-Atlantic region. Map courtesy NOAA, tropicaltidbits.com
Overview
An Arctic frontal system will work its way through the Mid-Atlantic region early tomorrow and some “post-frontal” snow can cause slick spots on the roads from about the time of the AM rush hour to around mid-day. Rain will break out later tonight in the DC-to-Philly-to-NYC corridor ahead of the Arctic front, but then as colder air filters into the region, precipitation will mix with and then change over to snow right around morning commute time on Thursday. Accumulations are likely to end up in the 1-3 inch range by mid-day tomorrow after the changeover takes place. Bitter cold conditions will follow the system for tomorrow night and Friday with overnight lows in the 10-15 degree range and highs doing no better than the 20’s to end the work week.
There can be a period of steady, moderate snow tomorrow morning as depicted here by the 12Z GFS (shown in dark blue) in the DC-to-Philly-to-NYC corridor. Map courtesy NOAA, tropicaltidbits.com
Details
The weather has turned noticeably milder today in the Mid-Atlantic region as low-level winds have shifted to a southwesterly direction ahead of the next incoming Arctic cold frontal system. Temperatures should reach well into the 40’s for afternoon highs - making today easily the mildest day of the week. An Arctic front will slowly edge its way towards the I-95 corridor later tonight initially bringing with it some rain to the region.
Upward motion in the atmosphere will be aided on Thursday by a weak short-wave (circled region) pushing overhead into the Mid-Atlantic region. Map courtesy NOAA, tropicaltidbits.com
Early tomorrow, the Arctic front will inch its way through the DC-to-Philly-to-NYC corridor and Arctic air will filter into the region from northwest-to-southeast. As a result, any rain that is falling early in the day will mix with and change over to snow - likely in the 5-8 AM time period which happens to coincide with at least part of the morning commute time. There can even be a brief period of moderate “post-frontal” snow on Thursday morning as upward motion in the atmosphere will be generated by a strong upper-level jet streak and a weak disturbance pushing overhead. Temperatures will slowly drop through the day and this could result in some slick spots on the roads while snow falls into the late morning or mid-day hours.
Following the snowfall, it’ll turn bitter cold tomorrow night with late night lows likely in the 10-15 degree range in most spots along the DC-to-Philly-to-NYC corridor. Despite some sunshine on Friday, temperatures will be confined to the 20’s for highs and the breeze will remain from a northerly direction. Low pressure will strengthen off the Carolina coastline later Friday night and it continues to look like this system will stay to the south and east of the I-95 corridor early this weekend. Currently, it appears the biggest impact from this next storm will be across the Carolinas to southeastern Virginia to the southern half of the Delmarva Peninsula.
Meteorologist Paul Dorian
Arcfield
arcfieldweather.com
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