Bill Hark
EF5
There is a possibility of tornadic supercells Saturday in the Mid-Atlantic. There is an approaching trough with an unstable airmass across the area. Dewpoints will be in the 70’s. At the 500mb level, there will be 30 to 40 winds from the SW in northern Virginia and Maryland. A low is predicted to move across West Virginia into Pennsylvania. Backed winds ahead of the low should produce sufficient shear for tornadic storms. The 12Z GFS for 00Z July 23 shows the low in northeast Penn while earlier at 18Z, the low is in Northeast West Virginia. In this scenario, the backed winds should be best in northeastern Maryland, southeast Penn. The 12Z run Eta has the low a bit farther south and I would expect the backed winds to be in Eastern Maryland, close to the Virginia border (near Washington D.C.) over to Delaware. I like this solution better and would pick Annapolis as a theoretical target. Negatives include slightly less forecast CAPE than than ideal (approx 1000).
A decision to chase will be made Saturday morning when I can get a better handle on the position of the low and area of backed winds in relation to the 500 mb wind max. The though of chasing across the Washington D.C. area doesn’t excite me. There is major construction on the WW bridge (495 crossing the Potomac near Alexandria) and there are often summer delays on the bridge over the Chesapeake by Annapolis. I also have to decide whether to blow off my wife’s friends who will be staying as houseguests Saturday afternoon to Sunday.
Bill Hark
A decision to chase will be made Saturday morning when I can get a better handle on the position of the low and area of backed winds in relation to the 500 mb wind max. The though of chasing across the Washington D.C. area doesn’t excite me. There is major construction on the WW bridge (495 crossing the Potomac near Alexandria) and there are often summer delays on the bridge over the Chesapeake by Annapolis. I also have to decide whether to blow off my wife’s friends who will be staying as houseguests Saturday afternoon to Sunday.
Bill Hark