Friday 9 a.m.
Here is my morning video showing how the weekend should turn out. As a special treat, you can watch the maps without having to see me!
This map shows the effects of a large upper air high pressure area that is building in the middle of the country. Such a system will create a flow from the northwest over the eastern Great Lakes and Northeast. That is why it should be dry this weekend with low humidity.
However, out in the Plains where low-level hot air is shooting northward, showers and thunderstorms will breaking out where the hot air interacts with cooler air to the north. Once those thunderstorms develop, they will ride southeastward early next week, raising the likelihood of thunderstorms over parts of the Northeast.
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).