Thursday 9:30 a.m.
The dreariness of yesterday morning in the Northeast has been replaced by dazzling sunshine and deep blue skies. A fast-moving cold front will send clouds streaming across the Great Lakes then New York and New England today and tonight, then a large high pressure area from western Canada will move for the start of the weekend. You can see and hear what this high pressure area should do in this video, along with what the flow behind it should accomplish later in the weekend.
In the short burst of cold air into the eastern Great Lakes tomorrow, showers will break out in the same areas that had them last night and this morning. Since this air mass is a little colder, snow showers are likely over the higher terrain southeast of Lake Ontario. Snow showers with lightning and thunder hit the Tug Hill Plateau last night, and the same thing can happen late tonight or tomorrow morning.
Severe thunderstorms are likely to break out in the middle of the country late tomorrow and tomorrow night, then rain and thunderstorms will advance into the Great Lakes for Saturday. A switch to a southwesterly flow aloft should keep the moisture mostly north of the Middle Atlantic states for much of Sunday... but as a cold front swings around a few showers should reach the area from southern New York to Virginia on Monday.
In most of the Northeast, it is a dazzling day, with the bright sun playing off the leaves that change hue by the day. It's quite a contrast from the dull dreariness much of the region experienced the first half of the week.
...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.