Tuesday 11 a.m.
Here is a video I prepared at 6:30 this morning. Since then, the worst rains have shifted toward coastal New Jersey. Earlier, Philadelphia's western suburbs got 2-4 inches of rain, turning roads into rivers, streets into streams and parking lots into ponds.
With more than 2 inches of rain in Philadelphia, the rainfall total since June 1 is now above 27 inches, which is about three times the average rainfall for the same period. So far this year, there has been more than 40 inches of rain, which is close to the average total for the entire year. There has also been more rain so far this year than all of last year.
This map shows the pressure pattern early this morning. The most intense rainfall was associated with the low pressure area over Delaware. The system also spawned damaging thunderstorm winds as it tracked from Delaware across southern New Jersey.
At first, the heaviest rain was in Philadelphia's western suburbs. This radar map shows the boundary between where it was pouring and where it was doing nothing.
As the low pressure area moved northeast, the heavy rain swept eastward across southern New Jersey.
...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.