Thursday 8:05 a.m.
In today's video, we look at the transition between warmth coming to the East Coast tomorrow into Saturday and a cool shot later in the weekend into early next week. By coincidence, the change almost matches the calendar change from summer to fall (at 10:49 a.m. EDT this Saturday). I say coincidence because there are many times when the calendar season changes and there is no immediate or noticeable change. In fact, there will be a warmup in the central and western Great Lakes on Monday, and the warming will spread on into the Northeast after that. So, the autumn chill is not taking over permanently.
There is a time-lapse movie at the end of the video. It was made last month on a day when thunderstorms were forming very close to my location. The sudden appearance of an outflow boundary may be noteworthy.
As the second low pressure area develops off the East coast, it will work in concert with a high pressure area from Canada to orchestrate cooler-than-usual conditions with showers in the Middle and North Atlantic states Thursday.
Looking ahead to <strong>next</strong> weekend, the Mothers Day Weekend, we see quite a difference between the GFS model and European models on where cold Canadian air is heading at 2 a.m. Sunday.
Rain is spreading across the Middle Atlantic states today. Dampness will linger from southern New York state to Virginia tomorrow even as the main rain area moves offshore.
For the rest of the week and this weekend, the upper-air "steering winds" will be arranged in two separate streams. The northern branch will send air from central Canada toward New England.
In the Northeast today, the low pressure area shown on this map will move to the East Coast today, pulling the front south as a cold front. Showers and gusty thunderstorm will affect areas south of the front while steady rain and gray skies are common to the north...
This map shows predicted temperatures for 2 p.m. ET today. This is about two hours before the daily high temperature is often reached. Note how close the chilly and warm air masses are to each other in the Northeast and eastern Canada.