textproduct: State College

WHAT HAS CHANGED

* Upgrade to level 2/4 excessive rain and flash flood risk for south central and southeast PA Thursday afternoon & evening

KEY MESSAGES

1) Torrential downpours and strong to locally damaging thunderstorm wind gusts may impact portions of south central PA Thursday afternoon and evening

DISCUSSION

KEY MESSAGE 1: Torrential downpours and strong to locally damaging thunderstorm wind gusts may impact portions of south central PA Thursday afternoon and evening

Most CAM guidance indicates a forward-propagating tstm cluster moving across southern PA/northern MD and the DelMarVa area tomorrow afternoon before tracking offshore the Mid-Atlantic coast by late evening. SPC upgraded to a level 2/5 SLGT risk which clips southern York and Lancaster Counties. The remainder of the Lower Susquehanna Valley is in a level 1/5 MRGL risk with potential for strong to perhaps locally damaging wind gusts dependent/contingent on location of strongest storms. The best CAPE and shear overlap is forecast farther to the south over the DelMarVa. HREF shows 2+ inch pwats available this area to drive very intense rain rates and increased flash flood risk. WPC will upgrade the excessive rainfall outlook to level 2/4 for Thursday in their updated forecast later this afternoon.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

Sub-VFR ceilings and visibility have improved to VFR at most terminals as of 18Z. Outside of a brief shower/t-storm downpour in the vicinity of KJST/KAOO/KUNV, expect VFR flying to continue into early tonight with waning shower activity.

Outlook...

Thu-Fri...T-storm impacts likely during the afternoon. AM low clouds and fog possible.

Sat...Reduced chance and more limited coverage of PM showers/t-storm.

Sun-Mon...Mainly VFR/no sig wx.

CTP WATCHES/WARNINGS/ADVISORIES

None.