Scattered showers and storms developed over western Pennsylvania during the afternoon of December 3, 2023, just ahead of an approaching cold front. In a high shear environment, a meager amount of CAPE developed when the sun briefly broke out west of the mountains.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS CTP wrote it up.
Scattered showers and storms developed over western Pennsylvania during the afternoon of December 3, 2023, just ahead of an approaching cold front. In a high shear environment, a meager amount of CAPE developed when the sun briefly broke out west of the mountains. This was enough to generate some embedded thunderstorms, some of which contained small hail, and one storm produced a report of wind damage in Clearfield County.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS State College, PA wrote its last area forecast discussion before the first event at Dec 3, 2:34 PM EST, 3 hours 8 minutes earlier.
Area Forecast Discussion National Weather Service State College PA 234 PM EST Sun Dec 3 2023 .SYNOPSIS... Low pressure lifting passing just to the west of Pennsylvania today will drag a cold front across the commonwealth this evening. This will usher in a chillier airmass tonight into Monday, along with some light lake-effect and upslope rain and snow showers. A weak clipper system will move through on Tuesday into Tuesday night. Temperatures will remain seasonably chilly before milder air begins to return toward the end of the week. && .NEAR TERM /THROUGH TONIGHT/... The steady rain has pulled east of the area, with a few spotty rain showers lingering across northern PA. It is kind of a murky afternoon out there for much of central PA, although it is mild for December. Some breaks in the clouds are beginning to form across western Pennsylvania, however, and we'll have to keep an eye on this area for possible convective development this afternoon. Strong shear exists over the area, thanks to a very strong 150+KT jet stream overhead, and any convection that develops could tap into the strong winds aloft. Any sfc-based CAPE that we can muster should be limited by the low December sun angle, but there could be just enough to help produce small hail and/or brief gusty winds in any storms that develop. SPC has painted a MRGL risk for svr wind/hail across the western highlands. The quickly lowering sun should stifle any convection before it makes it very far to the east this evening. As the cold front pulls east of the area, a chillier airmass will begin to filter in overnight and we'll hold onto a 40-50% chc of rain/snow showers across the western highlands. The highest elevations could possibly see a light coating of snow by daybreak on Monday. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... Monday will be chillier, with scattered rain/snow showers continuing across the northern and western highlands. Little in the way of snow accumulation is expected during the daylight hours. Any lingering rain/snow showers across the highlands will dissipate Monday night, with lows dipping into the upper 20s to low 30s areawide. By Tuesday, a weakening Alberta Clipper system will cross the Midwest and spread a shield of light rain/snow into western PA later in the day. Temperatures will likely be a bit too warm for much snow to accumulate during the daylight hours. This system will quickly pass to our south Tuesday night. Light precip will continue and we could see some light snow accumulation (mainly over the western highlands) before the precip tapers off early Wed. Wednesday looks like a chilly day with a breezy NW wind developing behind the departing clipper. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... Medium range guidance maintains a chance of snow showers on Wednesday with a slow to depart upper trough axis propogating east of the Commonwealth by Wednesday night, and an inverted sfc trough/weak clipper low passing south of the Mason Dixon line. Northerly flow and upper level ridging builds over the region on Thursday maintaining fair and cool conditions before zonal flow pattern resumes late in the week. Coldest conditions expected Wed/Thu before rebounding above climo levels by next Friday/Saturday. Might have to watch potential for some light overrunning precipitation along the NY border Thursday or Thursday night, if temps are still cold enough, that could result in light mixed precip. But for now consensus keeps most precip north of the PA/NY border. Otherwise, rising 500mb heights ahead of organized storm over the west- central U.S. should also keep mild conditions into next weekend. GFS/ECMWF displaying their usual fast/slow bias with this system with CMC a middle ground with round of precip for later Sunday/Sunday night (very low confidence on timing). && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... IFR conditions remain widespread into this afternoon as warm front sluggishly lifts but buckles along the Allegheny Front. Central and Eastern airfields should remain stuck with persistent lower cigs and vsbys (fluctuating between IFR and MVFR into this afternoon). Brief improvement to MVFR conds spreading over the western Laurel Highlands (Cambria and Somerset) currently, and model soundings indicate 150-250+ J/kg of elevated MUCAPES propogate across the Alleghenies late this afternoon and evening. Cold front approaching this evening with aforementioned instability ahead of it will support scattered to numerous showers to last into the evening over the west and northwest. A few rumbles of thunder can't be ruled out with these showers over the Mtns of Western PA where the marginal destabilization occurs ahead of the cold front. LLWS also possible at the western TAF sites (KJST, KAOO, KUNV) into this evening as llvl inversion ~2k feet persists. The threat for LLWS may continue to expand and impact KIPT, KMDT and KLNS for up to several hours between 00-05Z Monday as the axis of the westerly low-level jet continues to move east. Outlook... Mon...MVFR/IFR western 1/3 with snow showers. Tue-Wed...Light rain/snow with sub-VFR likely. Thu...Chance of rain or snow. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && SYNOPSIS...Dangelo/Evanego NEAR TERM...Dangelo/Evanego SHORT TERM...Dangelo/Evanego LONG TERM...DeVoir/Steinbugl AVIATION...Lambert/DeVoir/Bauco
Hazardous Weather Outlook National Weather Service State College PA 337 AM EST Sun Dec 3 2023 PAZ012-018-019-025>028-033>037-041-042-045-046-049>053-056>059- 063>066-040845- Northern Clinton-Northern Centre-Southern Centre-Blair-Huntingdon- Mifflin-Juniata-Somerset-Bedford-Fulton-Franklin-Tioga- Northern Lycoming-Sullivan-Southern Clinton-Southern Lycoming-Union- Snyder-Montour-Northumberland-Columbia-Perry-Dauphin-Schuylkill- Lebanon-Cumberland-Adams-York-Lancaster- 337 AM EST Sun Dec 3 2023 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...Monday through Saturday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. PAZ004>006-010-011-017-024-040845- Warren-McKean-Potter-Elk-Cameron-Clearfield-Cambria- 337 AM EST Sun Dec 3 2023 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...Today and tonight. Strong to severe thunderstorms with gusty winds and small hail are possible this afternoon. .DAYS TWO THROUGH SEVEN...Monday through Saturday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
Special Weather Statement
National Weather Service State College PA
517 PM EST Sun Dec 3 2023
PAZ005-010-011-017-024-025-032245-
McKean PA-Cameron PA-Clearfield PA-Blair PA-Cambria PA-Elk PA-
517 PM EST Sun Dec 3 2023
...A LINE OF GUSTY SHOWERS WILL IMPACT EASTERN ELK...CLEARFIELD...
SOUTHEASTERN MCKEAN...NORTHERN BLAIR...CAMERON AND CAMBRIA COUNTIES
THROUGH 545 PM EST...
At 516 PM EST, Doppler radar was tracking a line of gusty showers
with embedded thunderstorms extending from 12 miles northeast of St.
Marys to near Portage. Movement was east at 50 mph.
HAZARD...Wind gusts up to 50 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Altoona, St. Marys, Clearfield, Hollidaysburg, Tyrone, Ebensburg,
Nanty-Glo, Cameron, Northern Cambria, Philipsburg, Woodland,
Curwensville, Emporium, Bald Eagle, Lakemont, Bellwood, Patton,
Cresson, Gallitzin, and Penfield.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4175 7820 4162 7821 4148 7805 4147 7799
4137 7799 4122 7809 4115 7804 4112 7811
4105 7806 4096 7808 4096 7817 4075 7837
4074 7812 4068 7822 4053 7817 4056 7814
4056 7813 4047 7813 4039 7891 4162 7861
TIME...MOT...LOC 2216Z 251DEG 41KT 4160 7844 4046 7861
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH
KFSpecial Weather Statement
National Weather Service State College PA
528 PM EST Sun Dec 3 2023
PAZ006-012-018-025-032300-
Potter PA-Northern Centre PA-Northern Clinton PA-Blair PA-
528 PM EST Sun Dec 3 2023
...A LINE OF GUSTY SHOWERS WITH POSSIBLE THUNDER WILL IMPACT WESTERN
CENTRE...SOUTHERN POTTER...NORTHERN BLAIR AND NORTHWESTERN CLINTON
COUNTIES THROUGH 600 PM EST...
At 527 PM EST, Doppler radar was tracking a line of gusty showers
with possible thunder extending from 21 miles northeast of St. Marys
to near Tyrone to Altoona. Movement was east at 45 mph.
HAZARD...Wind gusts up to 50 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Altoona, Tyrone, Wharton, Keating, Philipsburg, Bald Eagle, Lakemont,
Bellwood, Williamsburg, Renovo, Galeton, Tipton, Snow Shoe, Clarence,
South Renovo, South Philipsburg, Sandy Ridge, Moshannon, Pine Glen,
and Monument.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4174 7762 4106 7768 4074 7823 4074 7812
4068 7822 4053 7817 4057 7813 4043 7816
4046 7855 4072 7835 4076 7837 4101 7806
4112 7811 4115 7804 4122 7809 4137 7799
4147 7799 4148 7806 4167 7821
TIME...MOT...LOC 2227Z 268DEG 38KT 4159 7820 4081 7826 4054 7843
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH
KFThe State College radar (KCCX), 22 km away, was scanning. The volume nearest the first event began at 22:43 UTC.
1 thunderstorm wind. Local standard time, as filed.
A severe thunderstorm producing winds estimated near 60 mph knocked down power lines near Morrisdale.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2023Every state in 2023This day in weather historyWarnings in Pennsylvania, December 2023
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1143399.