A huge difference on the NAM MOS and GFS MOS for Monday. The NAM has 71 while the GFS has 82 degrees at Philadelphia International Airport. Our current forecast high is 77 degrees. Extensive cloudiness and showers though could easily prevent us from getting into the upper seventies and there is definitely a path there for lower maximum temperatures on Monday . Tomorrow's forecast is one of very low confidence. The models have speed up the timing of precipitation for tonight and are also not in much in agreement on the actual amount. More details on the precipitation forecast can be found in the post written by Tom from earlier today.
After Wednesday, there is still the slight chance of some showers as some of the model guidance has slowed down the arrival of high pressure as the low currently responsible for the clouds and showers takes a long time to clear to the northeast. I have taken a more optimistic route and will not insert shower chances at this time.
As for the GFS and the tropics, the GFS 24 hours later at 12z today has shifted this " potential" storm (around the end of the month into early September) into the Gulf of Mexico. Other models are not even in range yet. Again, I view this more as a trend to be prepared for a possible increase in tropical activity potentially involving the U.S. in some way or another. More drastic changes are quite likely on the GFS and we have 12 days to watch the developments.
This weatherman is a bit under the weather today.... so that is all for now!