Tuesday 9 a.m.
Yes, the GFS operational run from yesterday afternoon included a forecast map for the afternoon of Oct. 10 that suggested heavy wet snow would be falling over the higher elevations of central and northern Pennsylvania. That map is below. The output from the same model run 12 hours later shows no such thing... just a Great Lakes low pressure area causing showers with fairly mild temperatures. That map is below the snowy version.
At this point, we cannot put much faith in either idea.
In the shorter range, southwest winds are sponsoring a warmup in the Northeast from today into tomorrow. A cold front will then move though to cause some showers and in places a thunderstorm... followed by cooler air. The front will stall in Virginia or Norrth Carolina, and a low pressure area forming along the front can then bring rain to the Middle Atlantic states on Friday. The video has more.
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.