Severe Thunderstorm Warning 283, NWS State College, PA

Area Forecast Discussion
National Weather Service State College PA
718 PM EDT Thu Oct 31 2019

.SYNOPSIS...
A potent cold front will cross the area this evening, bringing
locally heavy showers and thunderstorms, along with strong wind
gusts. Much colder weather will follow for the weekend, along
with generally dry conditions.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
6 pm update... Things progressing about on schedule early this
evening, as squall line with embedded meso-vortices continues to
push through central PA. Best threat of damaging winds and
isolated tornadoes will be south of I-80 and east of I-99
through 10 pm. Farther north, strong winds will be more
isolated, with heavy downpours the more prominent threat.

Further details can be found below.

Previous discussion... 145 pm update... We're becoming
increasingly concerned about an intense squall line barreling
through much of central PA, between about 6 and 9 pm. Damaging
winds, including isolated tornadoes, remain legitimate threats.

Early afternoon satellite imagery continues to show some
thinning of the persistent cloud cover across WV and MD, edging
into south-central PA. This jives well with high-resolution
model guidance, which showed destabilization to the tune of
anywhere in the 300-700 j/kg range late this afternoon, within a
narrow wedge just ahead of the approaching cold front and south
of I-80. Given exceptionally strong low-level wind field (925 mb
values over 60 kt and 850 mb values nearing 80 kt), robust QLCS
development (including isolated tornadoes) is a prime
consideration. Our expectation is that severe weather watches
will be forthcoming later this afternoon into the evening for at
least portions of central PA. We will continue to closely
monitor, and will likely issue a heads-up Special Weather
Statement to add more specific timing.

Once the front crosses east of the region later tonight, strong
cold advection, via W-NW flow, will set in. Post-frontal rain,
and even wet snow showers, will be most numerous over the
northern mountains and the Allegheny ridges, while downsloping
should promote at least partial clearing down towards the
Susquehanna Valley. After very mild highs around 70 this
afternoon, readings by daybreak will range from the upper 30s-
mid 40s, along with a stiff breeze. Speaking of this breeze, a
tight pressure gradient should support frequent gusts of 40-50
mph later tonight, hence continuance of our Wind Advisory for
portions of central PA.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/...
Strong, gusty winds on the backside of the departing storm will
continue into Friday morning. The gusty winds will decrease
through Friday afternoon as the tight pressure gradient quickly
unwinds with an area of high pressure spreading across the
northern Appalachians.

The weather pattern will turn noticeably colder through the
weekend with temperatures running a solid 5-10 degrees below
average for early November. A reinforcing shot of colder air
accompanying an upper level trough will bring a brief period of
lake effect snow showers to the far northwest zones Saturday
night into Sunday. Not expecting more than a slushy coating to
an inch accumulation in the favored snowbelts. An increasingly
unfavorable trajectory will spell an end to the lake effect
activity by Sunday night.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Broad cyclonic flow aloft associated with a mean upper trough
over southeast Canada will result in a chilly stretch of weather
through next week with reinforcing bouts of cold air maintaining
below normal temperatures. Areas downwind of the Great Lakes
appear most favorable for precipitation which may be rain or
snow (mix) depending on time of day vs. night.

&&

.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
00z update... Restrictions (briefly as low as IFR/fuel
alternate) will persist through 03-05z ahead of the cold front
in showers and embedded thunderstorms. KMDT/KLNS have the best
chance at significant convective wind gusts.

Once the front goes by, post-frontal restrictions in rain/snow
showers are likely at KBFD and KJST, with conditions improving
to VFR elsewhere.

Strong W gusts of 25-35 kt should persist through late Friday
morning, before starting to subside.

.Outlook...

Sat...Mostly VFR.

Sun...Possible restrictions at KBFD and KJST in lower clouds, as
well as rain and snow showers.

Mon and Tue...Mainly VFR.

&&

.HYDROLOGY...
A band of heavy rain will accompany a strong cold front across
central PA this evening. A swath of 1-2 inches are forecast with
locally higher amounts. Flood risk is mainly confined to urban
and poor drainage areas especially where leaves block drains.
Sharp rises are also possible on small streams which are most
vulnerable to minor flooding issues.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 10 AM EDT Friday for PAZ004>006-010>012-
017-018-024-025-033-034-037.

&&

SYNOPSIS...Jurewicz
NEAR TERM...Jurewicz
SHORT TERM...Steinbugl
LONG TERM...Gartner/Steinbugl
AVIATION...Jurewicz
HYDROLOGY...

Hazardous Weather Outlook
National Weather Service State College PA
642 PM EDT Thu Oct 31 2019

PAZ004>006-010-011-037-012245-
Warren-McKean-Potter-Elk-Cameron-Tioga-
642 PM EDT Thu Oct 31 2019

...WIND ADVISORY IN EFFECT UNTIL 10 AM EDT FRIDAY...

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.

   Wind Advisory.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

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

   Wind Advisory.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

PAZ019-026>028-035-036-041-042-045-046-049>053-056>059-063>066-
012245-
Southern Centre-Huntingdon-Mifflin-Juniata-Fulton-Franklin-
Northern Lycoming-Sullivan-Southern Clinton-Southern Lycoming-Union-
Snyder-Montour-Northumberland-Columbia-Perry-Dauphin-Schuylkill-
Lebanon-Cumberland-Adams-York-Lancaster-
642 PM EDT Thu Oct 31 2019

...TORNADO WATCH 686 IN EFFECT UNTIL MIDNIGHT EDT TONIGHT...

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.

   Tornado Watch.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

A blast of much colder air and strong southwest to west wind gusts
up to 40 mph will occur tonight into early Friday.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report significant hazardous weather.

PAZ012-018-025-034-012245-
Northern Clinton-Northern Centre-Blair-Bedford-
642 PM EDT Thu Oct 31 2019

...TORNADO WATCH 686 IN EFFECT UNTIL MIDNIGHT EDT TONIGHT...
...WIND ADVISORY IN EFFECT UNTIL 10 AM EDT FRIDAY...

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.

   Tornado Watch.
   Wind Advisory.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

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

   Wind Advisory.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report significant hazardous weather.

PAZ017-024-033-012245-
Clearfield-Cambria-Somerset-
642 PM EDT Thu Oct 31 2019

...WIND ADVISORY IN EFFECT UNTIL 10 AM EDT FRIDAY...

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.

   Wind Advisory.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

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

   Wind Advisory.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report significant hazardous weather.

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Special Weather Statement
National Weather Service State College PA
750 PM EDT Thu Oct 31 2019

PAZ042-046-049-051>053-010030-
Columbia PA-Southern Lycoming PA-Sullivan PA-Union PA-
Northumberland PA-Montour PA-
750 PM EDT Thu Oct 31 2019

...STRONG THUNDERSTORMS WILL AFFECT PARTS OF NORTHUMBERLAND...
LYCOMING...MONTOUR...COLUMBIA...UNION...AND SULLIVAN COUNTIES UNTIL
830 PM EDT...

At 750 PM EDT, Doppler radar indicated strong showers along a line
extending from near Hughesville to Milton. Movement was northeast at
50 mph.

Very heavy rain is expected.
Wind gusts 40 to 50 mph are possible.

Locations impacted include...
Milton, Lewisburg, Muncy, Watsontown, Hughesville, Montgomery, New
Columbia, Allenwood, Jerseytown, Iola, Jamison City, Waller,
Lairdsville, Central, Biggertown, Ricketts Glen State Park, Exchange,
Fairmount Spgs, Delaware Run and Muncy Valley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

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

Turn around don't drown.

&&

LAT...LON 4149 7624 4131 7631 4120 7631 4094 7696
      4129 7682 4134 7672 4131 7660 4136 7668
      4155 7632 4154 7623
TIME...MOT...LOC 2350Z 236DEG 45KT 4126 7676 4101 7688

Banghoff

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
751 PM EDT THU OCT 31 2019

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

0706 PM     TSTM WND DMG     2 NW WOOLRICH           41.22N  77.41W
10/31/2019                   CLINTON            PA   911 CALL CENTER

            TREES DOWN IN WOODWARD AND GALLAGHER TWPS

&&

EVENT NUMBER CTP1901732

COLBERT

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE STATE COLLEGE PA
802 PM EDT THU OCT 31 2019

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

0640 PM     TSTM WND DMG     CHAMBERSBURG            39.93N  77.66W
10/31/2019                   FRANKLIN           PA   FIRE DEPT/RESCUE

            MULTIPLE TREES AND WIRES DOWN

0706 PM     TSTM WND DMG     2 NW WOOLRICH           41.22N  77.41W
10/31/2019                   CLINTON            PA   911 CALL CENTER

            TREES DOWN IN WOODWARD AND GALLAGHER TWPS

0745 PM     TSTM WND DMG     GETTYSBURG              39.83N  77.23W
10/31/2019                   ADAMS              PA   911 CALL CENTER

            NUMEROUS TREES DOWN ACROSS THE COUNTY.

&&

EVENT NUMBER CTP1901731 CTP1901732 CTP1901733

COLBERT