Wednesday 11 a.m.
Strong thunderstorms with heavy rain came and went across eastern New England, slowing rush hour traffic to a crawl (swim?) in Providence and then Boston. Things has since settled down. Very dry air aloft has now moved over western Pennsylvania and western and central New York... and this will suppress new thunderstorm development today. However, a short wave trough aloft moving east-northeast from West Virginia is sending clouds into the area from southern Pennsylvania to Virginia, and the disturbance may help to set off a new round of thunderstorms in the I95 corridor this afternoon. The National Weather Service Storm Prediction Center suggested that the greatest threat for damaging winds and large hail will be from the Delmarva Peninsula (the Peninsula that includes parts of DELaware, MARyland and VirginiA). Around 11 a.m., a new thunderstorm fired up over western Long Island.
A cold front from the northern Plains will cross the Great Lakes tomorrow night and Friday then reach the East Coast on Saturday. This front will sponsor thunderstorms along and ahead of it. One question is whether the front stalls temporarily along the Northeast coast or instead simply moves away to allow quick clearing on Saturday. We'll be looking at that issue in the reports tomorrow and Friday. Cooler and drier air will follow the front.
A large thunderstorm developed last evening just east of my house. We got no measurable rain, but a few miles to the east the rain was so heavy that many motorists who would otherwise have kept on going (slowly) pulled off the road. At one point, outflow clouds moved over then northwest of our house. I expect to show a time lapse of this on my video tomorrow, but this picture is a still shot taken during the event.
In the Northeast, a high pressure area now in control will be reinforced by another high from northeastern Canada. In the "what could go wrong?" department, a batch of cloudiness has appeared east of New England and has been spreading southwestward toward the New Jersey coast this morning.
The clouds over parts of the region are starting to break up, a sign that the predicted drier air from the northeast is making progress.
Cloudiness covers a large area. A few pockets of clearing show up where south winds ride downhill from mountains to lowlands. Air warms and dries with descent. Notice clearing downwind (northwest of) the Smoky Mts.
So, there could be more showers at times late next week as forest we can tell. For now we are stumped. But, it is our beleaf that this weekend you will like being outside. I know a dogwood. It may be a little cool for the beech, but you can take your dog for walk in the bark. What about next weekend? Don't ax.
If the pattern turns out damp as suggested by this map for Sunday, it could turn gray and drizzly from D.C. to New York City for early next week. If the high does not move offshore and no disturbance approaches from the west, it would be sunny and warm.
Two things stand out: (1) a warmup this weekend and early next week (the top graph), and (2) the overall dryness for the weekend and early next week. This graph is for Philadelphia.