Wednesday 9 a.m.
Early this morning, some heavy showers and thunderstorms straddled I95 from Washington, D.C., to New York City. In some individual thunderstorms, the rain has been heavy enough to cause street flooding, and more episodes of that will take place today. This is part of the same disturbance that caused local flooding in Batavia, N.Y., yesterday and at other spots from central Pennsylvania through West Virginia and at places farther southwest.
Once the current shower zone moves offshore, hotter, humid air will drift east to send temperatures to or past 90 degrees for at least three consecutive days from D.C. to near New York City. Computer models show cool fronts reaching the Northeast late Sunday or Monday then again a few days later.
No tropical storms are targeting the Northeast at the moment, but the tropical Atlantic has come alive with several trackable features. You can read this morning's tropical weather feature here.
In today's video, we look at the period from today (Wednesday) through early next week.
After thunderstorms moves through in late afternoon clouds, the sky often clears. Around and just after sunset at ground level (but not yet at cloud height), the sunlight can illuminate the bottoms of clouds. This scene appeared west of my location in the middle of Pennsylvania last evening.
map shows predicted rainfall between now and next Wednesday. This will need to be watched in order to assess the risk of flooding.
Looking farther ahead, it appears a summer version of THE POLAR VORTEX will send much cooler air into the Great Lakes and then the Northeast. The first map shows the flow aloft next Tuesday night. The second map shows what could be a heat wave a week and a half later!
There were numerous thunderstorms yesterday. This is the lightning stroke map covering the period from 8 ET yesterday morning to 7:30 ET this morning. Thunderstorms will be less numerous today, but any that do form can cause briefly strong and gusty winds.
One area of concern is Lake Erie, where unprepared boaters could suddenly be blasted by 60-mph winds. The National Weather Service Storm Prediction Center has outlined a large area where the threat of strong wind exists. The map is below today's forecast video.
Tomorrow, a cold front will cross the Great Lakes, then reach the Northeast by the end of Wednesday. Today, a southwesterly current of very warm air is evident on the surface pressure map.
The center of Arthur (shown here at noon ET) should pass less than 50 miles southeast of Nantucket this evening, causing heavy rain and gusty winds across much of eastern New England. Meanwhile, the Great Lakes and much of the Appalachian region have a lovely Fourth (but take a jacket or sweater as you head out to the fireworks).