Bad Comma

Wednesday 10 a.m.

Yes, the headline could be interpreted as a misspelled way of writing how a New Englander might say bad karma, but there is a comma-shaped feature on the weather map, and when it passed through western Virginia, it dumped such heavy snow that more than 250,000 people lost power. As the eastern part of this swirling cloud mass reached Richmond, Va., this morning, there were thunderstorms followed by snow. This video gives the overall forecast idea for the Northeast, then I will come back to the "bad comma."

The cloud pattern in the East roughly resembles a comma, and a circular comma head is where the heaviest snow was occurring. The picture at the start of my video (above) shows where the comma was at 6 a.m. You can see that it moved a good distance between then and 9:32 a.m. when this picture was made.

I think the main forecast issue for later today, tonight and into tomorrow, is where the comma head migrates. It looks likely to graze the Philadelphia area later this afternoon (most of it passing to the southeast), passing southeast of New York City (suggesting not much snow there), then heading toward eastern New England. The Boston, Providence and New Bedford area could get some accumulation late tonight and tomorrow. The overall storm will likely change size and shape in time, so other factors will come into play. This means the storm should continue to cause wide variations over short distances. The forecast models have shown that the back edge of the precipitation will move more slowly tomorrow over eastern New England than it did farther south today.

Once the storm leaves, milder air will spread eastward from the Midwest. In Boston, the temperature may return to the 40s on Sunday and 50s Monday and Tuesday. The warmup will reach D.C. to Philadelphia during the weekend. Sunday will be the shortest day of the year because the change to daylight time means the day has only 23 hours. We might think of it is a benchmark of spring when you can take a walk after dinner with daylight for the first time since before Halloween.