Tuesday 9 a.m.
The upper-air current arriving in Pennsylvania this week originates over the Gulf of Mexico, so it is no surprise the main weather theme is warmer and more humid than typical for the season. However, computer models suggest that on Sunday, the flow reaching Pennsylvania will have originated in western Canada. Translation: warmer, then chillier. This video has more:
The details of the weather pattern are far less clear-cut than the overall trend. For example, there has been rain, some heavy, in a corridor extending from Pennsylvania to Virginia. Pittsburgh has been near the western edge; Philadelphia just east of the eastern edge. Farther south, violent thunderstorms developed in east-central North Carolina. Here is a map showing where precipitation was at 10 a.m. EDT.
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.
Tomorrow is the anniversary of the birth (in 1564) and death (1616) of William Shakespeare. For this weekend, we expect no Tempest in the Hamlets of the Northeast because no Merchant of Menace will be nearby.