Flash Flood Warning 27, NWS State College, PA

Area Forecast Discussion
National Weather Service State College PA
321 PM EDT Wed Jul 25 2018

.SYNOPSIS...
Rich subtopropical moisture and heavy downpours will finally
move east of the Commonwealth late tonight. Drier conditions are
expected on Thursday with just a slight chance of a shower. An
upper low and associated cold front will push southeast into the
region on Friday. By early next week, an area of low pressure
will likely approach Pennsylvania from the Ohio Valley.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Slow moving heavy rainers will last well into the evening hours
across much of the Flash Flood Watch area. Flash Flood Watches
remain in effect through 06z. Richest plume of subtropical
moisture with 2"+ PW has been nudged east of the area. However
approaching upper trof and associated cold front pushing across
northwest PA is acting on plentiful moisture environment (PW
remains 1.5" to 1.8") across eastern portions of the central
PA to produce sct-numerous SHRA and isold TSRA with heavy
downpours. The combination of high PW and moderate instability
will support locally heavy rain amounts through late evening
so the flash flood threat remains in effect through late
tonight.

CAMS continue to indicate spot 3-4" amounts over the eastern
half of central PA, where flooding is already widespread.
Additional heavy rain will worsen existing flooding through the
early to mid evening hours with 1 to 2 inch per hour rates
likely.

For the second half of the night, the approaching upper trof and
associated sfc cold front will push SE across the region
bringing an end to the siege of anomalous deep layer moisture
and locally heavy rainfall. Surface ridging and clearing skies
across NW and central areas should set the stage for areas of
late night fog.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
Any lingering early morning showers will end very early Thursday
morning giving way to clearing skies as drier air filters in
behind the front. The return of partly to mostly sunny skies
should allow temperatures to rebound to the 80s over most of the
region by afternoon. Have maintained just a chance chance of a
shower or tstorm by late afternoon over the northwest counties
in association with upper low crossing the Grt Lks.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Guidance remains in fairly good agreement into next week with an
upper level low over eastern Canada and a surface front that
pushes southeast into Central PA Thursday night and slows during
the day Friday possibly stalling over Southern PA. Scattered
showers and thunderstorms are expected with the front. Daytime
heating on Friday will help increase instability and a favorable
wind profile may lead to isolated severe storms in the late
afternoon and evening. The greatest risk is expected to be over
the Lower Susquehanna Valley.

High pressure will build into western PA Friday night bringing
some drying and clearing with some lingering coulds and showers
in the southeast. Weak shortwave moves southeast Saturday with
an isolated shower possible. Patchy fog overnight. Southwest
flow and weak disturbances will keep low chance showers or
thunderstorms in the forecast through Monday. A stronger system
will move into PA Monday night into Tuesday with more
significant chances for rain. Cold front moves through late
Tuesday and again stalls over the Lower Susq Valley.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
A continuation of the frequent shower/heavy rain pattern is
expected into this evening. Prevailing MVFR conditions for the
most part, with shorter duration IFR reductions in periods of
+RA. High confidence in widespread MVFR to LIFR conditions
tonight. A wind shift to the west should maintain low cigs
across the western airspace late tonight into Thursday.

.Outlook...

Thu-Sun...Scattered mainly afternoon showers/t'storms possible
with brief reductions.

&&

.HYDROLOGY...
A general decrease in the areal extent and intensity of showers
is expected late this morning. However, a resurgence of heavy
showers and possible thunderstorms is expected over central and
eastern Pa this afternoon.

Given the already wet ground across the eastern half of the
state, any additional heavy rain will pose a very serious
stream flooding threat, with eventual river flooding later this
week. The threat of locally heavy rain should abate tonight or
early Thursday, as high pressure builds into the area.

&&

.CLIMATE...
*Wettest July on record at Harrisburg and Williamsport

Month-to-Date total precipitation of 10.27 inches at Harrisburg
and 10.97 inches at Williamsport ranks as the wettest July on
record at both sites.

The previous wettest July at Harrisburg was 1969 with 9.72
inches. The previous wettest July at Williamsport was 1992 with
9.65 inches.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until 2 AM EDT Thursday for PAZ006-012-018-
019-025>028-034>037-041-042-045-046-049>053-056>059-063>066.

&&

SYNOPSIS...DeVoir/Fitzgerald
NEAR TERM...DeVoir/Fitzgerald
SHORT TERM...DeVoir/Fitzgerald
LONG TERM...Watson
AVIATION...DeVoir/Steinbugl
HYDROLOGY...
CLIMATE...

Hazardous Weather Outlook
National Weather Service State College PA
110 PM EDT Wed Jul 25 2018

PAZ004-005-010-011-017-024-033-261715-
Warren-McKean-Elk-Cameron-Clearfield-Cambria-Somerset-
110 PM EDT Wed Jul 25 2018

This Hazardous Weather Outlook is for central Pennsylvania.

.DAY ONE...This Afternoon and Tonight.

The probability for widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

PAZ006-012-018-019-025>028-034>037-041-042-045-046-049-050-056-
261715-
Potter-Northern Clinton-Northern Centre-Southern Centre-Blair-
Huntingdon-Mifflin-Juniata-Bedford-Fulton-Franklin-Tioga-
Northern Lycoming-Sullivan-Southern Clinton-Southern Lycoming-Union-
Snyder-Perry-
110 PM EDT Wed Jul 25 2018

...FLASH FLOOD WATCH IN EFFECT THROUGH LATE TONIGHT...

This Hazardous Weather Outlook is for central Pennsylvania.

.DAY ONE...This Afternoon and Tonight.

Please listen to NOAA Weather Radio or go to
weather.gov/StateCollege on the internet for more
information about the following hazards.

   Flash Flood Watch.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Strong to severe thunderstorms with gusty winds and small hail
are possible Friday afternoon.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

PAZ051>053-057>059-063>066-261715-
Montour-Northumberland-Columbia-Dauphin-Schuylkill-Lebanon-
Cumberland-Adams-York-Lancaster-
110 PM EDT Wed Jul 25 2018

...FLASH FLOOD WATCH IN EFFECT THROUGH LATE TONIGHT...

This Hazardous Weather Outlook is for central Pennsylvania.

.DAY ONE...This Afternoon and Tonight.

Please listen to NOAA Weather Radio or go to
weather.gov/StateCollege on the internet for more
information about the following hazards.

   Flash Flood Watch.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Severe thunderstorms with damaging winds 60 mph or greater and
large hail exceeding 1 inch in diameter are possible Friday
afternoon.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.