Special Weather Statement, NWS State College, PA

Area Forecast Discussion
National Weather Service State College PA
426 AM EDT Sat Jul 17 2021

.SYNOPSIS...
A cold front over the eastern Great Lakes will drift very
slowly to the south through the upcoming weekend as several
weak waves of low pressure ride northeast along it. The very
warm and humid airmass across Pennsylvania ahead of the front
will help to create numerous showers and scattered
thunderstorms.

Locally heavy rain and isolated strong wind gusts will once
again push through central PA Saturday afternoon and evening.
Drier air should push south into the northern part of the
Commonwealth on Sunday, though scattered to numerous showers and
a few thunderstorms are likely across the Lower Susquehanna
Valley.

A slow moving upper trough is likely to linger over the area
into much of next week, bringing overall drier conditions and a
reprieve from excessive humidity.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Slow moving front across northern PA continues to keep light to
moderate rain in place, with heavy showers/embedded storms
continuing down across the lower to mid Susquehanna Valley.
Fortunately, these latter areas didn't receive much rain earlier
and should thus be okay in terms of flooding tonight.

The heavy rain threat may attempt to pick up again across
portions of NW PA overnight along/ahead of the stalled frontal
boundary as a surface low traverses Lake Erie. Aloft, the right
entrance region of an upper level jet focuses persistent showers
and thunderstorms with locally heavy rainfall there. Flash
Flood Watch remains in effect for a large portion of north
central PA into portions of the Poconos tonight through Saturday
evening, with several rounds of heavy rainfall likely to
produce excessive runoff on nearly saturated surface soil
conditions.

Farther southeast, activity will continue to wane with a
relatively quiet period of time from late tonight into Saturday
morning. Focus for heavy rains shifts southward by Saturday
afternoon as convection fires from the central mountains
eastward through the Middle to Lower Susquehanna River Valley.
Will continue to monitor the potential expansion of FLash Flood
Watches to include the Saturday period over the southern and
especially southeastern half of central PA.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/...
Rich moisture plume will stay draped across much of Central PA
Saturday, bringing max coverage and highest intensity of
convective rainfall, and raising potential flood concerns again
for areas that have been very wet lately. WPC coordinated MDT
Excessive Rainfall risk over the region for Saturday.

A cold front will slowly cross PA through the day Saturday,
bringing rounds of showers and storms across the entire area.
The airmass in front of the cold front will be hot and juicy
with precipitable water values approaching or slightly above
2". Best chance for flash flooding over the Middle to Lower Susq
River Valley comes Sat afternoon and evening, so may very well
end up further expanding the current Flash Flood Watch. After
an evening maximum in intensity and coverage, front drops
southeastward and south of the Mason Dixon line by early Sunday.
Showers linger into Sunday morning behind the frontal passage,
but the heavy rain threat should be over by then.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Persistent upper level troughing with a mean west-northwest flow
aloft will bring a series of cold fronts through central PA next
week. Timing of these fronts is uncertain with max POPs weighted
toward the afternoon and evening hours. Each front will be
accompanied by scattered showers and t-storms, but with much
lower PWATs (available deep moisture) we expect the probability
of heavy rainfall to remain low. CPC outlooks tilt the odds
toward below average rainfall and below normal temperatures
beyond midweek. SPC has noted that the overall speed of the flow
aloft associated with the broad upper troughing is fcst to
remain rather weak. The weak flow combined with lack of well-
defined shortwave troughs and differences with frontal timing
favors a low predictability for severe weather. Lastly, we were
keen to utilize a 50/50 weighting of NBM with the consensus
multi-model blend which trends daytime temps closer to or just
below seasonal averages through midweek.

&&

.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
Low vis and cigs likely overnight with FG and BR at IPT and
BFD, with patchy fog possible elsewhere.

More showers and storms expected tomorrow with restrictions in
+TSRA.

Outlook...
Sat...Restrictions in SHRA/TSRA
Sun...Showers gradually sag southeast, reductions possible.
Mon-WED...Isolated to scattered P.M. showers/t-storms.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through this evening for PAZ004>006-010>012-
037-041-042-045-046-051>053-058.

&&

SYNOPSIS...Guseman/Lambert/DeVoir
NEAR TERM...Guseman/Lambert/DeVoir
SHORT TERM...Guseman/Lambert/DeVoir
LONG TERM...Guseman/Steinbugl
AVIATION...Gartner/Wagner

Hazardous Weather Outlook
National Weather Service State College PA
1126 PM EDT Fri Jul 16 2021

PAZ017>019-024>028-033>036-049-050-056-057-059-063>066-180330-
Clearfield-Northern Centre-Southern Centre-Cambria-Blair-Huntingdon-
Mifflin-Juniata-Somerset-Bedford-Fulton-Franklin-Union-Snyder-Perry-
Dauphin-Lebanon-Cumberland-Adams-York-Lancaster-
1126 PM EDT Fri Jul 16 2021

This Hazardous Weather Outlook is for central Pennsylvania.

.DAY ONE...Tonight.

The probability of widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Scattered strong to severe thunderstorms with gusty winds and hail
are possible Saturday afternoon and evening. Locally very heavy rain
of over 2 inches may occur in less than one hour where a few
thunderstorms train over the same location.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report significant hazardous weather.

PAZ004>006-010>012-037-041-042-045-046-051>053-058-180330-
Warren-McKean-Potter-Elk-Cameron-Northern Clinton-Tioga-
Northern Lycoming-Sullivan-Southern Clinton-Southern Lycoming-
Montour-Northumberland-Columbia-Schuylkill-
1126 PM EDT Fri Jul 16 2021

...FLASH FLOOD WATCH IN EFFECT THROUGH SATURDAY EVENING...

This Hazardous Weather Outlook is for central Pennsylvania.

.DAY ONE...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...Saturday through Thursday.

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.

Scattered strong to severe thunderstorms with gusty winds and hail
are possible Saturday afternoon and evening. Locally very heavy rain
of over 2 inches may occur in less than one hour where a few
thunderstorms train over the same location.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report significant hazardous weather.

Special Weather Statement
National Weather Service State College PA
433 AM EDT Sat Jul 17 2021

PAZ004-170930-
Warren PA-
433 AM EDT Sat Jul 17 2021

...STRONG THUNDERSTORMS WILL AFFECT PARTS OF WARREN COUNTY UNTIL 530
AM EDT...

At 432 AM EDT, Doppler radar indicated strong thunderstorms along a
line extending from near Findley Lake to Corry to near Columbus to
near Riceville to 7 miles east of Guys Mills. Movement was northeast
at 45 mph.

Very heavy rain is expected.
Wind gusts up to 45 mph are possible.

Locations impacted include...
Warren, Columbus, Youngsville, Russell, Spring Creek, Scandia,
Lottsville, Grand Valley, Garland, Warren South, Sugar Grove,
Starbrick and Bear Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Minor flooding may develop. Do not drive into water covering the
roadway.

&&

LAT...LON 4200 7892 4189 7901 4168 7961 4200 7960
TIME...MOT...LOC 0832Z 241DEG 38KT 4206 7972 4195 7963 4187 7961 4177
7971 4165 7983

Lambert