textproduct: State College

WHAT HAS CHANGED

Flood Watch issued through late tonight across the southeast zones for potential flash flooding.

KEY MESSAGES

1) Severe thunderstorms capable of damaging winds and heavy rainfall remain possible today into this evening.

DISCUSSION

KEY MESSAGE 1: Severe thunderstorms capable of damaging winds and heavy rainfall remain possible today into this evening.

The second of two shortwaves embedded in the NW flow of a deepening SE Canada and Ern U.S. trough (will be located across the Upper Glakes at 12Z) and will move quickly SE and bring at least another 1-2 rounds of MDT-HVY SHRA/TSRA across the CWA today into this evening with localized additional rainfall amounts of over 2 inches given the rich moisture with PWATS of 1.5-1.7 inches across all of the CWA.

The target for the greatest number of SHRA/TSRA is over our SE CWA where a FLash Flood Watch was posted and extends through 2 AM EDT WED.

Models close off the mid and upper low over SE Ont and New York State late tonight/Wed.

Some heavy rain potential will linger into Wednesday as the slow moving upper low dips over northeast PA/SE NY before drifting East toward southern New England Wed night. 36-48 hour storm total rainfall could exceed 3 inches over some parts of the northeast CWA by Thursday morning.

AVIATION /08Z TUESDAY THROUGH SATURDAY/

Complex set of TAFs for today, with spotty SHRA/TSRA increasing in coverage across portions of central PA during the predawn, followed by more numerous SHRA/TSRA alongside lowering cloud ceilings as a trough of low pressure moves across the region during the morning & afternoon. VFR is favored outside of any SHRA/TSRA during the predawn hours. Gradual improvements behind the low pressure expected after 18-21z, although low clouds could redevelop across the Laurels and northern mountains later tonight.

A more defined cluster of showers and storms associated with the trough will move west to east across our area between the early morning and late afternoon, resulting in prevailing MVFR- IFR ceiling restrictions with periodic MVFR-IFR visibility restrictions. Heating may be sufficient for strong to severe thunderstorms across eastern Pennsylvania (best chance at KMDT/KLNS), with gusty/damaging winds being the primary threat.

Outlook...

Wed...Restrictions likely with IFR to MVFR stratocu and SHRA/TSRA beneath upper low

Thu...Improving conditions with lingering -SHRA. Patchy AM fog.

Fri...Mainly VFR.

Sat...Patchy AM fog. Restrictions possible in isolated showers/storms mainly in the south.

CTP WATCHES/WARNINGS/ADVISORIES

Flood Watch through late tonight for PAZ057>059-063>066.