Thursday 10 a.m.
Thunderstorms raced from Pittsburgh to Philadelphia in less than seven hours this morning. Wind gusts to 50-60 mph hit a number of locations, but for most people the intense lightning and cloudburst of rain made the biggest impression. Heavy rain will now head from New York state across southern and central New England. Dry, pleasant weather should take over in the Northeast to start the weekend, but showers and thunderstorms can return to the Great Lakes Saturday and reach the I95 corridor later Sunday.
Here are the Northeast and Chicago area videos from this morning.
More than 110,000 lightning strikes occurred in the northeast third of the nation in the 24 hours ending at 11 a.m. EDT today (June 13).
I will be out of the office until July 1, but I expect to post here occasionally.
A storm strengthening off the Middle Atlantic coast will cause episodes of rain and cool gusty winds from Maryland to Maine. The heaviest rain today is focused on the Washington, D.C., to New York City area. Later tonight and tomorrow, the heaviest rain and strongest winds (gusts of 30-40 mph) should spread northeastward across New England. As the storm slowly departs, the weather will improve from southwest to northeast. This map shows the circulation around the storm as of 9 a.m. ET.
The reason for this is a growing and then stalling storm aloft. This map shows the predicted circulation around the storm on Wednesday evening, showing how the moisture could keep going round and round until the storm leaves.
This mornng, showers were moving across the lower Great Lakes region. A band of thunderstorms developed near Chicago before 6:30 a.m. CT and reached the southwest Michigan shoreline an hour later (8:30 a.m. ET). The following maps show the shower zone and Chicago area lightning.
The tropics have been more active recently. This map shows various entities that area being tracked and analyzed. Hurricane Gonzalo stands out clearly.
A couple of days ago, the storm entering the East had a stronger circulation than it does now. Here is the pressure analysis from earlier this morning. Several minor disturbance can be seen, and trough lines representing those have been sketched on the map. Note that there is little difference in temperature from western Pennsylvania to Wisconsin.
The rain band is only 100-200 miles wide, but it is moving slowly. This map shows its location at 10 a.m. today. Once the main rain band passes, it won't be quite as warm as it was when the rain started. However, by mid-October standard, it will still be mild.