Wednesday 8 a.m.
The morning video shows why sunshine should prevail across most of the Northeast right into the weekend.
On Monday, my backyard in the middle of Pennsylvania had its first significant rain in weeks, and there was a a great amount of lightning and even some hail. I was making timelapse movies using intervals of just under 1 second per shot. In the past, I have captured some lightning strikes this way (and saved the individual frames with the lightning as still images). Typically, I use an interval between 3 and 10 seconds depending the rate of cloud movement. When the cloud motion is rapid, a short interval is needed. Otherwise, the clouds would look like they are going so fast that the viewer cannot see the details. Here are couple of lightning pictures from late Monday, Sept. 3, 2013.
This bolt meanders quite a bit.
This bolt is straighter and more vertical than the other one.
While lightning strikes happen suddenly, the thunder can go on for a long time. This is because you first hear thunder coming from the part of the part of the spark that is closest to you. After this, you hear thunder that emanated from parts of the spark (or sparks) that were farther away. The curving or zig-zag shape of the lightning stroke accounts for some of the variation in sound as the thunder continues. Since it takes about 5 seconds for sound to travel 1 mile, you can count out 1accuweather, 2accuweather, 3accuweather and so on to help calculate the number seconds between the light and the boom.
A frontal zone separating cool to mild air to the north from really warm air to the south is becoming established from Illinois to New Jersey. An area of rain is moving east near and just north of the front. This map shows the setup.
Between yesterday morning and early this morning, quite a bit of lightning occurred. There can be some lightning all the way to the East Coast with this cold front, but the activity is likely to diminish. This map shows the distribution of lightning strikes in the (almost) 24-hour period ending at 7:30 ET this morning
The peak of the upcoming warmup should come on Monday for much of the Northeast. This map shows computer projections of temperatures at 4 p.m. ET Monday afternoon. Note the 80+ area in Pennsylvania. Cooler air will arrive by midweek.
As a storm slowly develops along the North Carolina coast, rain that was affecting areas of Michigan, Ohio and western Pennsylvania will tend to redevelop farther east and south. A flow from the east (see map) will keep it cool through tomorrow from New York City to Boston.
A sunny triangle is framed by a band of clouds moving southeast from Wisconsin, rain clouds over the Southeast and the western fringe of a North Atlantic storm.
Jumping ahead almost two weeks, map is the 500mb flow forecast for Mothers Day. If correct, the Middle and North Atlantic states would have a sunny day with afternoon temperatures as high as the 80s! Please remember the models do best in the short range.