Tuesday 10:20 a.m.
A frontal zone moving south through the Northeast today will be on a line from Virginia to Illinois tomorrow. The front separates really hot air to the south from more moderate air to the north. Thunderstorms have been breaking out in the boundary zone, and that will continue. Earlier this morning, strong thunderstorms race through the Chicago area causing wind gusts past 60 mph along with sheets of rain. Rainfall in Chicago is now just over the long-term average for the first 24 days of July.
As a low pressure area develops along the western end of the front then tracks toward the lower Great Lakes, the front will move northward ahead of it and southward behind it. Chicago may face temperatures well up in the 90s tomorrow, with the same thing possible in parts of the Middle Atlantic states on Thursday. Violent thunderstorms can continue to break out in the the frontal zone the next three days... and the area just south of the track of the next low pressure area could have destructive thunderstorms. Here is today's video:
Thunderstorm activity has been plentiful, and this map shows the lightning strikes recorded from 10 a.m. EDT yesterday through just about the same time this morning. Just over half a million lightning strikes are recorded here. No. Don't ask me to count them (you would need a much larger map to even try!).
On the map, one band of rain is along the coast at the north edge of the picture, the second is entering the Sierra range straight east of San Francisco, and the third extends from Los Angeles northeast to Las Vegas and on from there.
Some bands of rain broke out in the I-95 corridor, the most important of which brought a batch of heavy rain to the New York City area between 8:30 and 10 a.m.
in response to the approach of a deepening trough from the Plains, a Midwest low pressure area will grow stronger as it moves east to arrive on the New England coast Saturday morning.
In the I-95 corridor from D.C. to NYC, temperatures will be up past 80 this afternoon. However, between now and Saturday, a major change is on he way.
In eastern New England, an onshore flow of cool damp air prevailed all morning. There could be a last-minute warmup this afternoon. The affected areas will certainly be warmer tomrrow morning than they were this morning.
Now, out-of-season warmth is set to be the rule through midweek from the Ohio Valley to much of New England. Peak leaf color in Pennsylvania and New Jersey ranges from now northern mountains) to Halloween (in parts of South Jersey).