Severe Thunderstorm Warning 122, NWS State College, PA

Area Forecast Discussion
National Weather Service State College PA
730 AM EDT Fri Aug 7 2020

.SYNOPSIS...
Showers and thunderstorms are likely across most of central PA
today. Locally heavy rainfall is possible with the greatest risk
of flash flooding in the lower Susquehanna Valley. The overall
coverage and probability of showers and storms will trend lower
(drier) through the weekend with temperatures climbing 5 to 10
degrees above average into early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Overall forecast remains on track. Current storm tracking along
I-80 corridor has been persistent/strong and recently ramped its
hail core to 1-2 inches. SPC may be adding a portion of the CWA
to a MRGL risk with the 13Z update.

Primary focus today will be on heavy rain/FF potential. WPC has
upgraded the lower Susquehanna Valley to a SLGT risk ERO (level
2 out of 4). Several factors will contribute to heavy rain/FF
threat in this area including but not limited to above normal
moisture/PW, slow storm motions/cell training/mergers, and wet
antecedent conditions. The dayshift should consider a short-
fused FF watch if hires models remain bullish with +RA signal.
Scattered to numerous afternoon/evening showers and storms
should fade and shift eastward tonight into early Saturday
morning.

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
Increasing influence of high pressure sfc and aloft should spell
a downward trend in diurnal convection to start the weekend.
Pcpn probs derived from a blend of NBM and HREF are generally
AOB 20% and focused across the eastern 1/2 to 1/3 of the CTP CWA.
MaxT24hourChange will be about +2 to +6 degrees warmer vs.
Friday. High confidence in dry conditions tomorrow night with
mainly clear skies and light winds suggesting valley fog
is possible into AM Sunday.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Fair weather should prevail on Sunday.

The longer term will feature a return of warmer weather, with
temperatures generally 5-10 degrees above average from Mon
through Wed as an upper ridge builds over the Eastern US.
Dewpoints climb back to the upper 60s and 70s for Tue and Wed,
and perhaps even the mid 70s in the Lower Susq. Combined with
temps in the upper 80s to near 90, this would mean Heat Index
values take a run at the upper 90s to near 100 in the Lower Susq,
so long as the low level moisture doesn't mix out in the
afternoon and cause the dewpoint to drop. Continued to knock
down afternoon dewpoints from NBM guidance across central and
northwestern zones Mon and Wed afternoon, where it looks like
drier air will mix down.

Weak forcing will favor isolated, pulse thunderstorms on
Monday, mainly in the northwest. A cold front sagging south on
Tuesday and Wednesday, combined with increasing humidity, should
trigger more numerous showers and thunderstorms both days.
Guidance seems to indicate the cold front may stall as it moves
through PA, resulting in at least one more day of unsettled
weather on Thursday.

&&

.AVIATION /11Z FRIDAY THROUGH TUESDAY/...
MVFR ceilings covering much of central PA early this morning
may drop to IFR for a short while around sunrise before
gradually lifting through the mid morning hours.

Bigger issue of the day is thunderstorm impacts. Ongoing
isolated convection being driven by weak trough moving through
will keep tstms mainly confined between FIG-UNV-IPT through
sunrise. But scattered showers/tstms will then begin to develop
areawide in the mid/late morning hours and become numerous for
the afternoon for central and eastern portions. These storms
will bring periodic short-duration cig/vis reductions to
terminals with exact timing tough to pin down. Storms will be
slow moving as well.

Convective activity should fade and shift eastward during the
evening hours into early Saturday morning. Fog restrictions
along with low clouds likely Sat morning, but conditions bounce
back to VFR quickly.

Outlook...

Sat-Mon...VFR. AM fog poss nrn valleys.
Tue...Front approaching fm W. PM TSRA, mainly W.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

SYNOPSIS...Steinbugl
NEAR TERM...Steinbugl
SHORT TERM...DeVoir/Dangelo
LONG TERM...Colbert/Banghoff
AVIATION...RXR/Banghoff

Hazardous Weather Outlook
National Weather Service State College PA
428 AM EDT Fri Aug 7 2020

PAZ004>006-010>012-017>019-024>028-033>035-037-041-042-045-046-
049>053-058-080830-
Warren-McKean-Potter-Elk-Cameron-Northern Clinton-Clearfield-
Northern Centre-Southern Centre-Cambria-Blair-Huntingdon-Mifflin-
Juniata-Somerset-Bedford-Fulton-Tioga-Northern Lycoming-Sullivan-
Southern Clinton-Southern Lycoming-Union-Snyder-Montour-
Northumberland-Columbia-Schuylkill-
428 AM EDT Fri Aug 7 2020

This Hazardous Weather Outlook is for central Pennsylvania.

.DAY ONE...Today and tonight.

The probability for widespread hazardous weather is low.

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

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

PAZ036-056-057-059-063>066-080830-
Franklin-Perry-Dauphin-Lebanon-Cumberland-Adams-York-Lancaster-
428 AM EDT Fri Aug 7 2020

This Hazardous Weather Outlook is for central Pennsylvania.

.DAY ONE...Today and tonight.

Slow moving showers and thunderstorms with heavy rainfall will pose
a risk of mainly localized flash flooding.

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

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report significant hazardous weather.

Special Weather Statement
National Weather Service State College PA
714 AM EDT Fri Aug 7 2020

PAZ012-019-041-045-046-071200-
Southern Lycoming PA-Southern Clinton PA-Northern Clinton PA-
Northern Lycoming PA-Southern Centre PA-
714 AM EDT Fri Aug 7 2020

...A STRONG THUNDERSTORM WILL AFFECT PARTS OF LYCOMING AND CLINTON
COUNTIES UNTIL 800 AM EDT...

At 713 AM EDT, Doppler radar indicated a strong thunderstorm near
Blanchard, moving east at 15 mph.

Wind gusts 30 to 40 mph and half inch hail are possible.

Locations impacted include...
Lock Haven, Jersey Shore, Carroll, Lamar, Mill Hall, Avis, Dunnstown,
Flemington, Castanea, Blanchard, McElhattan, Mackeyville, Bald Eagle
State Park, Beech Creek, Loganton and Lock Haven University.

LAT...LON 4105 7717 4099 7763 4107 7766 4109 7762
      4111 7768 4116 7770 4131 7727
TIME...MOT...LOC 1113Z 252DEG 15KT 4110 7758

Steinbugl