Special Weather Statement, NWS State College, PA

Area Forecast Discussion
National Weather Service State College PA
546 PM EDT Mon Jun 21 2021

.SYNOPSIS...
Hot and humid conditions for the first full day of summer 2021
will help to fuel a few rounds of gusty, and in some cases,
severe thunderstorms this afternoon and evening. Showers will
continue tonight and exit the southeast part of the area later
Tuesday. Temperatures will trend cooler through midweek before
moderating into the weekend. The precipitation pattern should
stay rain- free through late week with an increasing chance of
showers over the weekend and into early next week.

&&

.NEAR TERM /THROUGH TUESDAY/...
540 PM update:

Been holding off on clearing the far nw area from the watch,
given high dewpoints and that the wind shift still to the west.

Earlier discussion below.

145 PM/1845Z:

Visible satellite imagery overlaid with several convective
parameter shows the atmos still capped by +8C mid level air
across much of Central PA and the Susq Valley, while a few deg C
of cooling along with increasing deep-layer shear and llvl
theta-e convergence was helping to consolidate 2 distinct lines
of strong to severe TSRA across NE Ohio/NW PA and nrn WVA.

Further intensification and merging of these lines of TSRA are
expected across the Eastern half of the CWA late this afternoon
and evening, with several discrete supercells expected within
the region of stronger llvl shear and more broadly- looped
hodographs across northern PA through 22Z highly conducive for a
widespread severe weather outbreak this afternoon/early this
evening.

Previous disc...

Broad warm sector over all of PA (to the SE of a potent, early
summer 990 mb sfc low just north of Georgian Bay) with juicy
dewpoints in the mid 60s to low 70s was leading to hefty sfc-
based capes of 2000-3000 j/kg over all but the far NW zones late
this morning. Nearly full sun and several more deg F of heating
will contribute another 500+ j/kg of CAPE.

SPC upgraded practically the entire CWA to an enhanced risk
with their midday update is prudent considering strong, deep-
layer shear of 35-40 kts of effective bulk shear and a growing
area of DCAPE in excess of 1000 J/KG across the Central Mtns and
Susq Valley.

A 2-3 hour period of strong to severe multicell/transient
supercell storms will grow rapidly upscale into a extensive
linear MCS over Central PA and the Susq Valley for the late
afternoon and evening hours with another bkn line of strong to
locally severe TSRA moving through the NW Mtns early this
evening along and just ahead of a cold front.

Heat+Humidity peaks this afternoon with max temperatures in the
mid 80s to low 90s and max heat index (HX) values forecast to
approach 100F in the mid and lower Susquehanna Valley. Forecast
max temperatures are a solid 5-10+ degrees above daily climo and
within a shouting distance of near-record territory.

Convection should weaken and decrease in coverage btwn 00-06Z due
to the loss of heating and increasing CINH. Hires models show a
relatively lull in precip around 06Z before showers ramp back up
across the southeast half of the CWA through Tuesday morning.

Minimum temperatures will have the most spread in recent nights
thanks to the cold front bisecting the area with lows ranging
from the upper 40s in the NW mtns to upper 60s in the far
southeast zones.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH 6 PM TUESDAY/...
540 PM update:

I cut back the back edge of the showers a bit faster, to fit
with other offices.

Earlier discussion below.

Showers will be across the southeast zones early Tuesday as
secondary front traverses the region. Rain should exit this area
by late in the day around 22-23Z based on the latest 06Z HRRR.
Temps will trend much cooler on Tuesday with 24hrMaxT deltas of
-20 to -25F lower vs. Monday.

Abnormally dry (below normal PWAT) airmass accompanying area of
high pressure will lead to relatively cool (refreshing to for
some) nights Tue & Wed with lows in the 40s and 50s. Some of the
usually colder spots in the northern tier may drop into the
upper 30s Tue night similar to 6/17. Rain-free conditions extend
trough midweek with temps going bullish trend starting a series
of higher lows and higher highs Wed/Wed night.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
The high will move to the east later in the week with warmer,
more humid air moving in from the south and east.

A cold front will approach from the west next weekend, but there
is still a great deal of uncertainty with the timing of that
front and precipitation it will bring. GFS and ECMWF have been
trending toward a slower solution on the movement of the front
and perhaps even the front stalling over PA next weekend into
early next week. This would result in an unsettled period with
multiple rain chances for central PA through the middle of the
week.

&&

.AVIATION /22Z MONDAY THROUGH SATURDAY/...
VFR expected for the next few hours western half of PA, and
through the late afternoon across the Susq Valley and points
east.

Widespread coverage of showers/tstms is expected this afternoon
with activity spreading from the NW across the CWA. These
storms will bring potential for locally strong wind gusts and
torrential rainfall as they impact the area through the
afternoon hours. Peak areal extent of TSRA expected between 18z-
00z.

A cold front will move through the CWA behind the convection
with winds turning more nwrly after 00z. This frontal passage
will likely be accompanied by a period of MVFR cigs, mainly
across the west.

Outlook...

Monday-Tuesday...more widespread showers/storms possible
areawide.

Wednesday-Friday...widespread VFR.

&&

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

&&

SYNOPSIS...Lambert/Steinbugl
NEAR TERM...Lambert/Steinbugl/Martin
SHORT TERM...Steinbugl/Martin
LONG TERM...Guseman/Travis
AVIATION...Lambert/Colbert/Wagner

Hazardous Weather Outlook
National Weather Service State College PA
639 PM EDT Mon Jun 21 2021

PAZ012-018-019-025>028-034>037-041-042-045-046-049>053-056>059-
063>066-221845-
Northern Clinton-Northern Centre-Southern Centre-Blair-Huntingdon-
Mifflin-Juniata-Bedford-Fulton-Franklin-Tioga-Northern Lycoming-
Sullivan-Southern Clinton-Southern Lycoming-Union-Snyder-Montour-
Northumberland-Columbia-Perry-Dauphin-Schuylkill-Lebanon-Cumberland-
Adams-York-Lancaster-
639 PM EDT Mon Jun 21 2021

...SEVERE THUNDERSTORM WATCH 302 IN EFFECT UNTIL 10 PM EDT THIS
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.

   Severe Thunderstorm Watch.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report significant hazardous weather.

PAZ006-010-011-017-024-033-221845-
Potter-Elk-Cameron-Clearfield-Cambria-Somerset-
639 PM EDT Mon Jun 21 2021

...SEVERE THUNDERSTORM WATCH 299 IN EFFECT UNTIL 8 PM EDT THIS
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.

   Severe Thunderstorm Watch.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report significant hazardous weather.

PAZ004-005-221845-
Warren-McKean-
639 PM EDT Mon Jun 21 2021

This Hazardous Weather Outlook is for central Pennsylvania.

.DAY ONE...Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report significant hazardous weather.

Martin

Special Weather Statement
National Weather Service State College PA
623 PM EDT Mon Jun 21 2021

PAZ052-057>059-212300-
Northumberland PA-Lebanon PA-Dauphin PA-Schuylkill PA-
623 PM EDT Mon Jun 21 2021

...STRONG THUNDERSTORMS WILL AFFECT PARTS OF NORTHUMBERLAND...
LEBANON...DAUPHIN...AND SCHUYLKILL COUNTIES UNTIL 700 PM EDT...

At 623 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from near Klingerstown to near Tower City. Movement
was northeast at 35 mph.

Pea size hail and wind gusts of 50 to 55 mph are possible.

Locations impacted include...
Pottsville, Shamokin, Minersville, Kulpmont, Elysburg, Pine Grove,
Fairview-Ferndale, Trevorton, Lykens, Tremont, Marshallton,
Williamstown, Tower City, Lavelle, Marlin, Forrestville, Branchdale,
Seltzer, Donaldson and Heckscherville.

LAT...LON 4049 7643 4049 7644 4044 7649 4063 7681
      4088 7661 4068 7620
TIME...MOT...LOC 2223Z 224DEG 29KT 4063 7672 4053 7651

Banghoff

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
627 PM EDT MON JUN 21 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0500 PM     TSTM WND DMG     KNOXVILLE               41.96N 77.44W
06/21/2021                   TIOGA              PA   911 CALL CENTER

            TREES/WIRES DOWN.

&&

Special Weather Statement
National Weather Service State College PA
641 PM EDT Mon Jun 21 2021

PAZ033-212300-
Somerset PA-
641 PM EDT Mon Jun 21 2021

...A STRONG THUNDERSTORM WILL AFFECT PARTS OF SOMERSET COUNTY UNTIL
700 PM EDT...

At 641 PM EDT, Doppler radar indicated a strong thunderstorm near
Farmington, moving east at 40 mph.

Wind gusts up to 50 mph are possible.

Locations impacted include...
Ursina, Confluence and Addison.

LAT...LON 3973 7941 3976 7940 3977 7938 3978 7939
      3979 7938 3978 7935 3980 7937 3982 7937
      3983 7938 3984 7938 3983 7917 3972 7919
      3972 7938
TIME...MOT...LOC 2241Z 265DEG 35KT 3978 7945

KF

Special Weather Statement
National Weather Service State College PA
649 PM EDT Mon Jun 21 2021

PAZ052-053-058-212315-
Columbia PA-Northumberland PA-Schuylkill PA-
649 PM EDT Mon Jun 21 2021

...A STRONG THUNDERSTORM WILL AFFECT PARTS OF COLUMBIA...
NORTHUMBERLAND...AND SCHUYLKILL COUNTIES UNTIL 715 PM EDT...

At 649 PM EDT, Doppler radar indicated a strong thunderstorm over
Wilburton Number One, moving northeast at 45 mph.

Pea size hail and wind gusts of 50 to 55 mph are possible.

Locations impacted include...
Mount Carmel, Shenandoah, Kulpmont, Ashland, Mcadoo, Oneida,
Nuremburg, Aristes, Numidia, Sheppton, Brandonville, Wilburton Number
One, Locustdale, Slabtown, Wilburton Number Two, Shumans, Shenandoah
Heights, Ringtown, Marion Heights and Kelayres.

LAT...LON 4075 7645 4082 7650 4103 7623 4095 7621
      4090 7604 4091 7600 4089 7597
TIME...MOT...LOC 2249Z 234DEG 41KT 4081 7640

Banghoff

Special Weather Statement
National Weather Service State College PA
700 PM EDT Mon Jun 21 2021

PAZ033-212315-
Somerset PA-
700 PM EDT Mon Jun 21 2021

...A STRONG THUNDERSTORM WILL AFFECT PARTS OF SOMERSET COUNTY UNTIL
715 PM EDT...

At 700 PM EDT, Doppler radar indicated a strong thunderstorm over
Mount Davis, moving east at 50 mph.

Wind gusts up to 50 mph are possible.

Locations impacted include...
Meyersdale, Mount Davis, Salisbury, Garrett and Callimont.

LAT...LON 3972 7931 3986 7931 3986 7898 3978 7889
      3972 7891
TIME...MOT...LOC 2300Z 271DEG 43KT 3977 7922

KF

Special Weather Statement
National Weather Service State College PA
712 PM EDT Mon Jun 21 2021

PAZ058-212330-
Schuylkill PA-
712 PM EDT Mon Jun 21 2021

...STRONG THUNDERSTORMS WILL AFFECT PARTS OF SCHUYLKILL COUNTY UNTIL
730 PM EDT...

At 711 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from near Tamaqua to Hamburg. Movement was northeast
at 35 mph.

Pea size hail and wind gusts of 50 to 55 mph are possible.

Locations impacted include...
Tamaqua, Hometown, Coaldale, Snyders, Port Clinton and New Ringgold.

LAT...LON 4070 7581 4063 7600 4058 7601 4057 7602
      4058 7604 4089 7597 4081 7589 4073 7576
TIME...MOT...LOC 2311Z 240DEG 32KT 4082 7593 4058 7600

Banghoff