Monday 9:45 AM
A storm crossing the Gulf states dropped heavy rain over a wide area, and the moisture is moving northeastward. However, the upper air trough supporting the rain is shown to weaken slowly on the computer model (I use this term interchangeably with numerical forecasts) maps, and so places in the Northeast should not match the Gulf states in the rainfall amount department. One thing that is apparent is with a persistent flow from the Gulf states to New England, it will be warmer than average for this time of year.
Last week at this time, I showed a GFS forecast map for Oct. 10 that suggested it could snow in central and northern Pennsylvania. I suggested the model would change looks over time and, in fact, the very next run has a warmer look and no snow. On the other hand, a typhoon re-curved over the western Pacific, and this kind of event has often been followed by an upper air trough n the East about 10 days later. The most recent runs of GFS has trended toward this trough in the East scenario, and this suggests next week will be quite a bit cooler than this week (with the first push of cooler air arriving this weekend).
The numerical forecasts (I use this term interchangeably with computer models) for next week will certainly change in various ways before next week arrives, but there are hints that the higher terrain downwind from the Great Lakes could get their first snow showers of the season next week. This map for next Thursday shows a close call setup for this:
Meanwhile, my daily video shows what we can expect this week:
you can see clear skies out ahead of the cold front that is causing showers and thunderstorms from Michigan to Missouri. The resulting heating will add fuel for developing thunderstorms ahead of the front this afternoon. The National Weather Service Storm Prediction Center highlights this in its outlook
While the Northeast and Great Lakes regions had fine weather much of the Fourth of July weekend, thunderstorms were very common in other parts of the country. This map shows lightning strokes from 7 a.m. ET yesterday until 6 a.m. ET today:
Over the Ohio Valley, rain is starting nudge northward again, prodded by one of a series of upper air disturbances embedded in the flow. It appears the rain will advance across Pennsylvania overnight, reach the area from New York City to Boston tomorrow... then head out to sea.
Farther north, the area from Chicago to Boston looks most likely to have sunshine and dry weather. Cloud cover will vary during the weekend, and I focus on that aspect of the weekend forecast in this video.
A band of heavy rain and locally violent thunderstorms moved from the New York City area at 4 a.m. to just past Boston (distance: 188 miles) by 9:30 this morning. Note the stunning contrast between where it is pouring (dark red) and where it has dried out.
On the map, showers and thunderstorms were located along and ahead of the gray line that cuts through Pennsylvania and along/ahead of the blue line. Both should be off the East coast by Thursday. Drier air from the Upper Midwest should filter into the Northeast later in the week.