Thursday 10 a.m.
With a weak high pressure area in charge, dry and pleasant weather should be the rule for the Northeast today and tomorrow. Showers are advancing across the western Great Lakes, and they could reach the Buffalo area tomorrow. The main weather maker this weekend wlll be a low pressure area and cold frontal system that will become better organized as they approach the East Coast.
There is still a lot of spread in model solutions for this storm. The European model develops a strong storm in the Carolinas on Sunday, then strengthens it even more as it heads to coastal New England on Monday. Such a storm would cause substantial rainfall from the Appalachians to the Atlantic coast. Then, as it slows down, moisture would wrap around the west side of the storm at the same time that chilly air pours in from the north. The result would be snow from the mountains of Pennsylvania up through central or eastern New York state.
The GFS starts with two storms, one near Maine and the other over Georgia, on Sunday. It then strengthens the northern storm as it moves into eastern Canada. If that happens, rainfall would be quite limited in the Middle Atlantic states, and by the time chilly air is drawn in from the north, it is too dry for much precipitation at all. Until the storm actually starts taking shape, the ultimate outcome will be uncertain.
This afternoon and evening, locally severe thunderstorms can occur from northernmost Texas to southern Iowa. Tomorrow, the area that seems to be at risk is much smaller.
...after all that, the point is that zone will be north of most of the eastern half of the country. It will be very warm to hot south of the jet stream. However, weakening cold fronts can advance south of the jet stream. then return north as the next disturbance in the flow approaches.
Yesterday, the temperature hit 92 at Newark, New Jersey, and 90 in Boston. The following map shows a northerly flow affecting the Northeast today, and so it will be noticeably cooler and less humid.
This map shows lightning strokes from 8 a.m. ET yesterday through 7:54 a.m. ET today. There was quite a bit of it in Utah, Colorado, New Mexico and Arizona. For the whole map, 156,172 lightning strokes were recorded.
Looking at the west-to-east upper air flow over New England well ahead of the storm, it seems like the hurricane should stay out at sea, However, as we look through the series of maps, we see the upper-air flow congealing into a strong eastern trough that helped the storm to come right up the coast instead of heading out to sea.
On this satellite picture, we can see the basically dry weather in the Eastern states. The cold front that will ease the midweek heat in the Northeast is shown by the band of thunderstorms in the Midwest. The thunderstorms may weaken and become more scattered as the front comes into the Northeast.
A storm in the tropical Atlantic is being observed for possible strengthening. This map shows the variety of models purporting to show where the center will go. Most solutions suggest it stays well offshore, but you will notice a few outliers suggesting more threat.