The Calm after the Storm

Synopsis:

After two days of warmer than average temperatures, a strong cold front will move through the Northeast on Saturday. This front will bring the chance for damaging winds, large hail, and an isolated tornado or two.  After it passes, high pressure will build and result in seasonably cool temperatures, mostly sunny skies, and comfortable dewpoints.

Weekend Outlook:

It will definitely be a stormy Saturday for Pennsylvania.  Both the NAM and GFS 1200Z models indicate a chance for an isolated storm in the western portion of the state during the morning hours.  Then, the cold front associated with the Canadian low will move through and bring strong to severe weather along with it.  NAM 4KM models show a squall line developing and moving into western PA by 1500Z, while NMM/ARW, NAM 12KM, and GFS models all show the line moving in later in the afternoon, around 1800Z.  Whatever the timing, the possibility of a strengthening lower jet, along with sufficient CAPE (~1500-2000 J/kg), might create enough vertical wind shear to support the development of supercells embedded within the squall line. 

Models indicate the squall line moving out of PA around midnight tomorrow, and up and out of New England by 1200Z Sunday morning.

Next Week:

The calm after the storm sets in Sunday morning after the front moves out to sea.  High pressure will settle in and bring cooler temperatures, mostly sunny skies, and little chance for precipitation through the middle of next week.

Matt Flournoy