textproduct: State College

WHAT HAS CHANGED

* Lifted the fog advisory. * Will likely issue a Flash Flood Watch for Sunday later on this shift.

KEY MESSAGES

1) Widespread rain will develop across the CWA Sunday morning and bring light to moderate amounts of one-quarter to three quarters of an inch. After a warm front moves into Central and Northern PA early Sunday afternoon, thunderstorms will develop near and to the south of this boundary bringing locally heavy rain in excess of one inch in just 20-30 minutes with the potential for localized flash flooding.

DISCUSSION

KEY MESSAGE 1: Widespread rain will develop across the CWA Sunday morning and bring light to moderate amounts of one- quarter to three quarters of an inch as the remnants of midwest TSRA/MCV moves east into the region.

Update: We are going to be (and in some cases have already begun) collaborating with our neighboring offices on a Flash Flood Watch for tomorrow/Sunday. Confidence is high in a FF threat, but narrowing down 1) where and 2) when the threat be highest and 3) when will it end are the major questions to answer.

Previous... After a warm front moves into Central and Northern PA early Sunday afternoon, some breaks in the otherwise widespread, multi-layered cloud cover will lead to MU CAPE values climbing into the 1000-1500 J/KG range per the latest HREF.

Thunderstorms will develop near and to the south of this boundary bringing locally heavy rain in excess of one inch in just 20-30 minutes with the potential for localized flash flooding.

ERO from WPC hydro forecasters has nearly all of the CWA (nrn tier = not yet) in the SLGT risk category for Sunday.

Clouds will thicken up tonight with a several hour period of steady light to moderate rain overspreading the state from west east during the early to mid morning hours Sunday, ahead of a warm front.

PWAT values will surge to 2.0+ inches across the part of the state near and to the south of Interstate 80 by late Sunday morning and stay there for the rest of the day. The warm front will lift into Central PA Sunday afternoon, before being followed closely by scattered thunderstorms with periods of torrential downpours in the afternoon and evening as a cold front pushes through.

Basin "Average" rainfall amounts Sunday will vary from around one-half of an inch across the Northern Tier Counties of PA to between 1 and 2 inches across the Southern Half of the state. Any training thunderstorms could put down 3 inches of rain which would trigger localized flash flooding of poor drainage areas and some streams/creeks.

AVIATION /13Z SATURDAY THROUGH WEDNESDAY/

High moisture values (Precipitable Water Values in excess of 1.4 inches) were present in the vicinity of KJST and KAOO South and east to near the I-81 corridor in Scent PA.

Clear skies and a very light easterly wind in this area overnight resulted in widespread Dense Fog, which will persist until 12-13Z today and lead to near zero vsbys and VV003 or less at KJST and KAOO. other TAF sites should stay AOA 5SM and CIGS above 2000 feet early today, though brief restrictions are possible through 12Z at KUNV and KBFD.

For the remainder of today and the first half of tonight, widespread VFR conditions with light wind will blanket all of the CWA as a ridge of surface high pressure slides across the eastern half of PA.

Conditions will steadily lower to MVFR with periods of IFR very late tonight and Sunday as a large area of steady light to moderate rain spreads in from the west in advance of a warm front.

Outlook...

Sun...Restrictions probable in showers/thunderstorms.

Mon-Tue...VFR most of the time. Chance of showers/tstm Monday.

Wed...Afternoon showers or a TSRA with brief restrictions possible. Otherwise, VFR.

CTP WATCHES/WARNINGS/ADVISORIES

None.