Summer's Last Stand

I do believe that Monday will be the last warm and humid day probably until next spring.  I think we can crack 80 with high dew points Monday....it will most assuredly feel summery.  The satellite below shows the streaming of moisture up into PA from the cut-off low over the Midwest and an old frontal boundary just off the east coast.  The red shows this moisture advection and the blue shows the old frontal boundary.  The black is what is waiting in the wings once this cut-off pulls away in the mid-week period.

The front will pass through on Tuesday giving us our last real threat of meaningful precip for awhile!  The upcoming period after Tuesday will be decidedly drier.  Oh, there will be some instability showers, but the pattern suggests a much drier time in the next 10 days!

This front will usher out the humid air that we will have in place now through Tuesday.  Below shows the near 70 dew points in SE PA.

It will be gradual, but the cooling will come in spades by Friday afternoon as a secondary shot of cold air from O Canada comes down and actually creates some lake effect rain showers due to the very cold air aloft at ~5000 feet!  Take a look at that diving trough!

The operational GFS is not as bullish as the Euro is as seen below.  The GFS is on the right.  The graphics below are for the upcoming weekend period.  Both show the dip in the jet stream, but the Euro is much more pronounced!

The ensembles of the GFS, however, do agree with the deep trough.  Remember, the ensembles are many models that are run at slightly different initialization.  The operational is only one of the the models in the battery.

So that is why I believe summer's last real stand is the next couple of days.  Thus the end of summer is now literally upon us as the autumnal equinox occurred last Friday.  And seeing that it is September 25, not only the end of summer but 31 years ago, it was the end of Led Zeppelin due to the death of John Bohnam.  It was a sad day in the world of Rock and Roll and for me as I had a ticket to go see Zep at the Pittsburgh Civic Arena in November.  So I'll leave y'all with this classic!

Have a good Monday!

Smitty

AA:  Summery the next couple of days then cooling down.  Looks to be pretty chilly for this upcoming weekend!