Thursday 10 a.m.
The moist air mass that was over the I-95 corridor yesterday has slipped offshore, and the drier air behind is promoting sunny weather. With the sunshine and a light flow from areas where it is hotter, temperatures will be heading high today through Saturday from Chicago to New York City. A strong low pressure area and cold front will come through the Great Lakes and Northeast later in the weekend. There could be some severe thunderstorms as that front advances. This video shows the basic forecast theme for the next few days.
This 24-hour lightning strike map (8 a.m. yesterday to 8 a.m. today EDT) shows the stunning boundary of the excessive heat wave that is roasting the south-central part of the country. South of the lightning zone, it's just searing sunshine with unrelenting heat. The picture probably contains the lightning strike that sent four people who were sitting under an umbrella at Wildwood, N.J., to the hospital. On a map with this scale, you can't see that one stroke, of course.
This map shows a projection from last night's European model. It shows an huge temperature difference in a short distance across northern and central New England.
A number of you have submitted weather photos and graphics that we really enjoy. One person with a keen eye for how to visualize weather and climate events is Ralph Fato of Connecticut, who graciously allowed me to use this graphic about snowfall.
Snowfall amounts yesterday were low from Philadelphia to New York City. Accumulations increased toward the north and northeast.
This map shows the NAM's projection for this Friday night. The isobaric pattern suggests there is a southwesterly flow of mild air from the Gulf states to the Middle Atlantic region. Farther north, we see evidence of the frontal boundary that separates the mild air from chillier air.
A new area of snow now over southern Minnesota should expand southeastward to reach Chicago this afternoon, streak to Pittsburgh this evening, then reach the Philadelphia/New York City area late tonight or early tomorrow morning. This map shows a low pressure area over Missouri.
This map shows expected accumulations.