textproduct: State College

WHAT HAS CHANGED

* A bit more cloud cover for Saturday. Rainy conditions for late Saturday and early Sunday.

KEY MESSAGES

1) A nice afternoon today, but increasing chance for widespread moderate to perhaps heavy rain late Saturday into early Sunday.

DISCUSSION

KEY MESSAGE 1: A nice afternoon today, but increasing chance for widespread moderate to perhaps heavy rain late Saturday into early Sunday.

Surface high pressure will drift across Upstate New York before moving off the Southern New England Coast tonight. A southeasterly to southerly flow will develop late tonight into Saturday and low level moisture lurking just south of the Mason/Dixon line will push steadily NE across the state on Saturday.

A notable axis of streamline convergence shifting gradually east across Central PA late Sat afternoon/Sat night will provide increasing llvl theta-E advection and numerous showers with several tenths of an inch of rainfall likely across at least the SE half to two thirds of the CWA by early Sunday.

A few PM TSRA are possible Saturday and/or Sunday afternoons, especially over the western mtns where MU CAPE will climb above 1000 j/kg with pocket of 0-1 KM EHI in the 1-1.5 m2/s2 range.

The timing of the thickening cloud cover late tonight/early Sat morning will allow for moderate radiational cooling of the ground tonight with the llvl inversion being difficult to break for the first half of Saturday across our Central and NE zones. So, Max Temps should turn out to be a few to several deg F lower than today's

A more-active (wetter) pattern is in store for Mon- Tues. But, the flat upper ridge over the southern half of the CONUS will make it difficult for deep moisture to make it into PA ahead of any shots of atmos forcing. The week could end dry as the upper ridge pumps up over the central CONUS.

AVIATION /15Z FRIDAY THROUGH TUESDAY/

Surface high pressure sliding by just to the north of the Central PA airfields will bring widespread VFR with excellent vsby and light/variable or a light North to Northeast breeze this afternoon.

Tonight will be mainly clear to start, with cloud cover overspreading the area from SW to NE late tonight/early Saturday as a disturbance approaches from the Tennessee Valley.

Some patchy drizzle is possible on the SE facing slopes of the Laurel Highlands and Western Mtns late tonight/early Saturday. Otherwise, it will be dry through much of Saturday morning.

Outlook...

Sat - Mainly VFR early, then MVFR conditions developing from SW to NE across the region Sat morning (SW PA) and Sat afternoon (NE PA).

Sun-Mon...Primarily VFR conditions, with some potential for afternoon SHRA/TSRA on at least a hit and miss basis.

Tue...Mainly VFR with a few showers possible over NW PA.

CTP WATCHES/WARNINGS/ADVISORIES

None.