Tuesday 9:45 a.m.
A southwesterly flow of warm, moist air ahead of a cold front is contributing to a band of rain and thunderstorms that stretches from the Ohio Valley into parts of the Middle and North Atlantic states. We expect some showers and thunderstorms to cross the I95 corridor from D.C. to Boston later today and this evening.
The cold front should slip south then stall from Virginia or Maryland to Kentucky tomorrow. With the front likely to make only limited progress, some additional showers may occur tomorrow from D.C. to New York City and on west. Most of New England should turn sunny.
In general, computer models suggest a low pressure area forms along the front in the Middle Atlantic states on Friday then slowly moves up along the coast this weekend. If that happens, it will be a damp weekend in the I95 corridor of the Northeast.
In contrast, most of the Great Lakes region looks like it will bask in sunshine with afternoon temperatures in Detroit and Chicago close to 70 and nights cooling to the 40s and 50s. The video has more.
In the longer range, the re-curving of the latest western Pacific typhoon may signal an upper air trough (and cool weather) in the Northeast in a week to 10 days.
Late September is not generally known for widespread thunderstorms, but this map shows near 50,000 lightning strokes in the period from 8 EDT last night until just after 8:30 EDT this morning.
In yesterday's report I made an analogy about predicting snow amounts using our 16 year old American Eskimo dog Sam as an example. I told Sam about it before taking this picture, but he just looked at me.
This map shows the pressure pattern around the big storm that some people in Boston and Providence are comparing with the Blizzard of '78.
In the worst-hit areas, plan for travel bans (for all non-emergency activities) because of impassable roads and extremely poor visibility. This map shows our projection for snow accumulations by early Wednesday. In many areas the heaviest snow should fall overnight and tomorrow morning.
In the worst-hit areas, plan for travel bans (for all non-emergency activities) because of impassable roads and extremely poor visibility. If you get stranded, rescue crews may not be able to reach you. Storms like this sometimes generate thunderstorms within the heaviest snow bands. The map shows predicted snow accumulations by early Wednesday.
It appears likely that many normal activities can go on through the day Monday, as long as the typical cautions for light to moderate snowfalls are observed. Tuesday will be an <strong>entirely different story</strong>. This map shows the GFS- predicted snowfall through 7 P.M. ET Monday:
The second storm we have been talking about will affect the Middle Atlantic region late Sunday and Sunday night. This GFS forecast map is for 7PM ET Sunday and shows precipitation amounts for the 6 hours up to that time.