Thursday 10 AM
As a cold front lumbers toward the East Coast, the warm, humid air mass out ahead of it is ripe for thunderstorm formation. Be alert for any signs or warnings about severe weather, especially in the zone outlined as "s" on this map.
Much chillier air will advance in the Northeast and Middle Atlantic regions tomorrow and tomorrow night, setting the stage for an unusually cool start to the Memorial Day weekend.
This is the Northeast video
This video is for the Chicago area, where the chill has already arrived,
We can use radar, satellite pics and other methods to predict thunderstorms. Here, a distant unseen storm is blocking part of the sunlight that is coloring the cirrus clouds.
This upper air map shows (1) there is no strong heatwave ridge over the Midwest or Northeast any more and (2) a broad trough populated with smaller disturbances will move from the Mississippi Valley to the Appalachians by Sunday.
On this satellite picture, we see the plume of moisture advancing northeastward from the Ohio Valley.
In this picture, the sun had set as seen from the ground. However, sunlight was able to light up the clouds from below to create this look outside my home:
Now, drier air has arrived, and most of the Northeast will have abundant sunshine today and tomorrow.
A front that will usher in slightly less humid air for the Northeast tomorrow will trigger locally strong thunderstorms today.
Thunderstorms will continue to erupt near the northern edge of the heatwave, enhanced by a series of disturbances rippling along in the upper air flow. This is the NWS Storm Prediction Center's severe thunderstorm outlook for today