Monday 10 AM
A cool front moving through the Northeast is ushering in less humid weather. It was a fine, comfortable morning in Wisconsin and Michigan, with temperatures outside the cities dropping into the 50s. Meanwhile, it was still oppressively humid from coastal New England through the Middle Atlantic states. Those areas will be a little cooler and less humid tomorrow (although the change will be much more subtle in Maryland than in New York and Massachusetts).
Humidity will increase again from midweek on as the winds become southerly and a low pressure area takes shape near the southern edge of the Great Lakes region. Both the European Model (ECMWF) and U.S. model (GFS) place the low pressure center over Pennsylvania on Friday, then take it northeastward during the weekend. This kind of a system would cause widespread showers and thunderstorms as it approaches and moves through. Another shot of cooler and drier air should follow the storm during later in the weekend and early next week.
The video has more:
This map shows estimated rainfall totals from July 30 through early this morning (Aug. 6). Comparing the map with actual rainfall totals, it is clear that the map overestimates the rain that fell... in many areas by more than a factor of two. The main thing I wanted to show was that there has been at least some meaningful rain during the past week in areas hard hit by drought... except for central and West Texas, where there has been virtually nothing. I am not considering the normally dry Western states for comparative purposes; at Los Angeles California, the average rainfall from June 1 though yesterday is only 0.12 of an inch, so the fact they have had no measurable rain in that period really does not mean much. In the same period, Savannah, Ga., has received just over 10 inches of rain, but even that amount is two and a half inches below average.
In the Northeast, a high pressure area now in control will be reinforced by another high from northeastern Canada. In the "what could go wrong?" department, a batch of cloudiness has appeared east of New England and has been spreading southwestward toward the New Jersey coast this morning.
The clouds over parts of the region are starting to break up, a sign that the predicted drier air from the northeast is making progress.
Cloudiness covers a large area. A few pockets of clearing show up where south winds ride downhill from mountains to lowlands. Air warms and dries with descent. Notice clearing downwind (northwest of) the Smoky Mts.
So, there could be more showers at times late next week as forest we can tell. For now we are stumped. But, it is our beleaf that this weekend you will like being outside. I know a dogwood. It may be a little cool for the beech, but you can take your dog for walk in the bark. What about next weekend? Don't ax.
If the pattern turns out damp as suggested by this map for Sunday, it could turn gray and drizzly from D.C. to New York City for early next week. If the high does not move offshore and no disturbance approaches from the west, it would be sunny and warm.
Two things stand out: (1) a warmup this weekend and early next week (the top graph), and (2) the overall dryness for the weekend and early next week. This graph is for Philadelphia.