Two clusters of storms pushed northeastward across the Lower Susquehanna Valley during the evening of September 8, 2023, each producing sporadic wind damage across York and Lancaster Counties.
Every event with a place to put it. Tap one for its entry below.
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.
Two clusters of storms pushed northeastward across the Lower Susquehanna Valley during the evening of September 8, 2023, each producing sporadic wind damage across York and Lancaster Counties.
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 Sep 8, 3:28 PM EST, 1 hour 38 minutes earlier.
Area Forecast Discussion National Weather Service State College PA 428 PM EDT Fri Sep 8 2023 .SYNOPSIS... A cold front will become nearly stationary over Central PA late today into Sunday. Daily showers and thunderstorms will form along and to the east of the front, with the bulk of the convection occurring in the late afternoons and evening hours. Temperatures will settle back close to normal for Sunday into Monday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Severe Thunderstorm Watch #674 recently issued for roughly the SE half of the CWA and will run through 03Z Sat. Sfc cold front drifted to near a KBGM to KUNV and KJST line as of 19Z, while a weak lee side trough was located across our far eastern CWA where sfc dewpoints were pooling around the 70F mark. SLightly warmer mid level temps across our SE zones has put a weak cap on the otherwise very unstable airmass with sfc-0.5km ML CAPE in the 2000-3500 J/KG range near and to the SE of I-81. Latest individual high res model members and the HREF shows several areas of convection gradually growing upscale/consolidating into a potent/small scale MCS as it moves NE late today/early tonight. This convection will be boosted by larger scale UVVEL associated with the thermally direct cell of a 50-60 KT SSWRLY jetlet lifting acrs Western PA. The greatest concentration of SHRA/TSRA with some brief torrential rains and potential for damaging microbursts will be first across the Laurel Highlands and SCent PA through 23Z, while rapid TSRA development will occur over the Lower Susq Valley between 21-23Z, with additional TSRA advecting into that area from the SW. Given the amount and location of the heaviest rain from yesterday's convection, the main concern for Flash Flooding will be across the Middle Susq Valley and Western Poconos where 1 hour FFG values are under 1.5 inches in spots. The greatest areal coverage will likely be found over and just to the east of the Susq Valley through this evening. Latest CAMs indicate the potential of localized 2+ inch amounts/3 hours, which could exceed FFG near the transition from the much higher FFG numbers south of I-81 to the aforementioned lower values further north. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/... Saturday currently looks cloudier and a bit cooler, and drier for much of the day with much more stable LLVLS as the cold front sags into the southeast part of the state. We should start the day with widespread stratus and areas of 1/2SM fog, especially in the Central Mtns and Susq Valley. Upper level ridging and the cooler surface temps should limit the chance of convection for much of the day. However, surging pwats ahead of a shortwave lifting up the Appalachians should result in a return of increasing POPS and good chance of late day and overnight convection. The airmass should remain relatively stable north of the stalled front, so the severe weather threat appears low, though the DAY2 ERO is still in the MRGL category. Most guidance tracks a remnant upper low over the Tennessee Valley northeast toward PA on Sunday. Increasing large scale forcing and surging pwats ahead of this feature should support a good chance of showers/tsra during the PM hours, as ensemble plumes depict. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... The upper-level pattern is likely to remain in place for much of next week, we can expect this to bring daily rounds of scattered showers and thunderstorms. This is supported by ensemble guidance showing agreement with the progressive pattern. Tuesday of next week is the only day with a break from the rain as the initial trough lifts towards the north east, and the next trough sets up to the west. Temperatures in the extended period are progged to be much cooler than the hot summer like temperatures we experienced this week. With the upper-level flow of cooler Canadian air pushing into the region, our temps will be near seasonal to slightly below average. && .AVIATION /21Z FRIDAY THROUGH WEDNESDAY/... Generally VFR conditions will persist into the early evening hours. However, the potential for lower cigs and vsbys will be increasing as the areal coverage of the convection expands NE. Following the late day early nighttime bout of convection with potentially brief, strong wind gusts and torrential rains, light wind and partial clearing/cooling temps in the wake of a weak cold front will lead to areas of 1/2SM fog between 07Z-13Z Sat, before cigs slowly lift later in the morning with sunshine breaking through by early in the afternoon, especially across the SE third of the CWA - near and to the SE of a KAVP to KSEG and KMRB line. VFR to MVFR cigs with mainly VFR vsbys should occur after 17Z Sat through early Sat evening, when we should see increasing convection developing NE into the state. Sat night, Sunday and into early next week will feature some showers and perhaps a storm now and then. Outlook... Sun-Mon...Scattered mainly afternoon and early evening showers and storms. Patchy fog to start both days. Tue...AM patchy fog. Otherwise mainly dry with VFR conditions. Showers could return Tuesday night. Wed...VFR with periods of IFR in SHRA/TSRA and areas of morning fog. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && SYNOPSIS...Lambert NEAR TERM...Lambert SHORT TERM...Lambert/Fitzgerald LONG TERM...Tyburski AVIATION...Lambert
Hazardous Weather Outlook National Weather Service State College PA 506 PM EDT Fri Sep 8 2023 PAZ004>006-010>012-017>019-024-025-033-037-041-042-045-046-092115- Warren-McKean-Potter-Elk-Cameron-Northern Clinton-Clearfield- Northern Centre-Southern Centre-Cambria-Blair-Somerset-Tioga- Northern Lycoming-Sullivan-Southern Clinton-Southern Lycoming- 506 PM EDT Fri Sep 8 2023 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...Tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. Showers and thunderstorms may contain heavy rain and gusty winds on Saturday. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. PAZ026>028-034>036-049>053-056>059-063>066-092115- Huntingdon-Mifflin-Juniata-Bedford-Fulton-Franklin-Union-Snyder- Montour-Northumberland-Columbia-Perry-Dauphin-Schuylkill-Lebanon- Cumberland-Adams-York-Lancaster- 506 PM EDT Fri Sep 8 2023 ...SEVERE THUNDERSTORM WATCH 674 IN EFFECT UNTIL 11 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...Saturday through Thursday. Showers and thunderstorms may contain heavy rain and strong to severe wind gusts on Saturday. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather.
Special Weather Statement
National Weather Service State College PA
144 PM EDT Fri Sep 8 2023
PAZ025-081815-
Blair PA-
144 PM EDT Fri Sep 8 2023
...A STRONG THUNDERSTORM WILL IMPACT CENTRAL BLAIR COUNTY THROUGH 215
PM EDT...
At 143 PM EDT, Doppler radar was tracking a strong thunderstorm over
Hollidaysburg, moving northeast at 15 mph.
HAZARD...Wind gusts up to 40 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Altoona, Hollidaysburg, Roaring Spring, Lakemont, Claysburg,
Williamsburg, Duncansville, Horseshoe Curve, Ski Gap, Canoe Creek
State Park, Royer, East Freedom, Tunnelhill, Newry, Peoples Natural
Gas Field, Allegheny Portage Railroad National Historic Site, Penn
State Altoona, Lakemont Park And Island Waterpark and Blue Knob Ski
Resort.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Very heavy rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
&&
LAT...LON 4036 7859 4037 7856 4045 7856 4047 7854
4050 7854 4053 7851 4054 7848 4063 7842
4045 7817 4030 7842 4030 7843 4027 7847
TIME...MOT...LOC 1743Z 222DEG 14KT 4039 7849
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH
TyburskiSpecial Weather Statement
National Weather Service State College PA
424 PM EDT Fri Sep 8 2023
PAZ017-024-025-082100-
Clearfield PA-Blair PA-Cambria PA-
424 PM EDT Fri Sep 8 2023
...A STRONG THUNDERSTORM WILL IMPACT SOUTH CENTRAL CLEARFIELD...NORTH
CENTRAL BLAIR AND NORTHEASTERN CAMBRIA COUNTIES THROUGH 500 PM EDT...
At 423 PM EDT, Doppler radar was tracking a strong thunderstorm
5 miles northeast of Ebensburg, moving northeast at 10 mph.
HAZARD...Wind gusts of 50 to 55 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Patton, Blandburg, Prince Gallitzin State Park, Irvona, Coalport,
Ashville and Chest Springs.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4081 7858 4064 7831 4057 7845 4050 7860
4057 7870
TIME...MOT...LOC 2023Z 219DEG 11KT 4060 7860
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...55 MPH
DangeloPreliminary Local Storm Report
National Weather Service State College PA
435 PM EDT Fri Sep 8 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0150 PM Tstm Wnd Dmg 2 NNE Whipple Dam State 40.72N 77.83W
09/07/2023 Huntingdon PA Trained Spotter
Widespread large trees down in Rothrock
State Forest.
&&Special Weather Statement
National Weather Service State College PA
543 PM EDT Fri Sep 8 2023
PAZ024-025-082215-
Blair PA-Cambria PA-
543 PM EDT Fri Sep 8 2023
...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN BLAIR AND SOUTH
CENTRAL CAMBRIA COUNTIES THROUGH 615 PM EDT...
At 543 PM EDT, Doppler radar was tracking a strong thunderstorm over
Portage, moving northeast at 5 mph.
HAZARD...Wind gusts up to 50 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Portage, Lilly, Spring Hill and Cassandra.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
A Severe Thunderstorm Watch remains in effect until 1100 PM EDT for
south central Pennsylvania.
&&
LAT...LON 4028 7865 4031 7868 4044 7866 4039 7850
4032 7860 4033 7862
TIME...MOT...LOC 2143Z 225DEG 6KT 4031 7863
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH
EvanegoSpecial Weather Statement
National Weather Service State College PA
604 PM EDT Fri Sep 8 2023
PAZ065-066-082230-
York PA-Lancaster PA-
604 PM EDT Fri Sep 8 2023
...A STRONG THUNDERSTORM WILL IMPACT SOUTH CENTRAL LANCASTER AND
SOUTHEASTERN YORK COUNTIES THROUGH 630 PM EDT...
At 604 PM EDT, Doppler radar was tracking a strong thunderstorm near
Red Lion, moving northeast at 10 mph.
HAZARD...Wind gusts up to 50 mph and penny size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Safe Harbor, Shenks Ferry, Brogue and Airville.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
A Severe Thunderstorm Watch remains in effect until 1100 PM EDT for
south central Pennsylvania.
&&
LAT...LON 3979 7645 3989 7652 3999 7643 3988 7632
TIME...MOT...LOC 2204Z 230DEG 8KT 3986 7643
MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH
EvanegoThe Sterling radar (KLWX), 132 km away, was scanning. The volume nearest the first event began at 22:05 UTC.
8 thunderstorm wind. Local standard time, as filed.
A severe thunderstorm producing winds estimated near 60 mph knocked down multiple trees along Canning House Road and Short Cut Road north of Brogue.
A severe thunderstorm producing winds estimated near 60 mph knocked down multiple trees in the vicinity of Stambaugh Lane and Chapel Church Road southeast of Craley.
A severe thunderstorm producing winds estimated near 60 mph knocked down multiple tree limbs onto wires along Kendig Road near the intersection of Berrydale Road on the northern end of Conestoga.
A severe thunderstorm producing winds estimated near 60 mph knocked down multiple trees and wires near the intersection of East Delp Road and Landis Valley Road east of Neffsville.
A severe thunderstorm producing winds estimated near 65 mph knocked down a large tree along with multiple wires down across Broad Street near the intersection of Front Street on the east end of Delta.
A severe thunderstorm producing winds estimated near 60 mph knocked down multiple trees and wires across Peach Bottom Road southwest of Wakefield.
A severe thunderstorm producing winds estimated near 60 mph knocked down multiple trees and wires along Furniss Road west-northwest of Eldora.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires across Jerusalem School Road east of Starview.
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, September 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: 1128991, 1128987, 1128988, 1128989, 1128990, 1128992, 1128993, 1128994.