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.
It appears that a large low pressure area will form in the Plains this weekend and then drift very slowly eastward next week. This could lead to a lot of rain over a large area. This map depicts the Euro model predicted rainfall between now at midday Saturday May 3rd.
Thunderstorms broke out in eastern New England this morning. Here is a lightning map showing strikes between 8 a.m. and 10:30 ET:
I'd like to think that my explanations of what was going on enlightened him, but we all know better! This map shows the distribution of lightning from around daybreak yesterday to the wee hours of the morning today.
Omega blocks are known for causing long periods of whatever kind of weather you had when the block was getting established. In other words, if it was rainy, you were in for more (perhaps a lot).
This satellite picture shows the storm that affected the Southeast on Saturday (1) , the frontal system that will reach the East Coast late tomorrow night (2) and a disturbance in the Pacific Northwest that may affect the Northeast at the end of the week (3) .
A deck of clouds about a half-mile overhead spread westward from the Atlantic to much of the I95 corridor from DC to Boston early this morning. These cloud decks can be a forecaster's nightmare in the spring because ...