A line of showers and thunderstorms crossed central Pennsylvania during the afternoon and evening of July 17, 2023. One cell in this line produced sporadic wind damage from Perry County into upper Dauphin County.
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.
A line of showers and thunderstorms crossed central Pennsylvania during the afternoon and evening of July 17, 2023. One cell in this line produced sporadic wind damage from Perry County into upper Dauphin 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 Jul 17, 2:20 PM EST, 3 hours 50 minutes earlier.
Area Forecast Discussion National Weather Service State College PA 320 PM EDT Mon Jul 17 2023 .SYNOPSIS... Wildfire smoke from western Canada will cover the area today, causing the visibility to be reduced to between 3 and 4 miles in many places. A weak cold front and upper level disturbance approaching from the Ohio Valley will spark an area of showers and thunderstorms that will move northeast and impact much of the Northwest half of Pennsylvania late today through early tonight. The upper low and trough over the Great Lakes and northern Ontario will only gradually shift into eastern Canada through the week. Several chances for showers and thunderstorms will occur until the weekend when we get a drier flow of air from the west. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... A hazy/smoky airmass covered the region this mid afternoon hour with just some high-based flat cu and cirrus streaming northeast overhead across the Central Mtns and Susq Valley. As noted earlier, the primary weather-maker for the next 8-12 hours will be a surface cold front (that extended from the Peninsula of SW Ontario through NW Ohio and Central Indiana at 1830Z. This surface feature will be collocated with the thermally direct, right entrance region of a 80 to 85kt 300 mb jet max which will help to create an area of focused/enhanced meso-b lift and a growing area of SHRA/TSRA over the Middle and Upper Ohio River Valley by the mid afternoon hours. Regional Dual-Pol radar mosaic shows the leading edge of this convection along a line from KIDI to KAOO and KHMZ and moving NE at about 22 KTS. The SHRA/TSRA will begin along a KFIG to KUNV and KRVL line between 2045Z and 2130Z and will continue into the evening hours. We expect to see this convective cluster strengthen/expand NE over the next several hours with some cores within the NE/SW band of 1000-1500 J/KG CAPE (per the 12Z HREF) approaching the threshold for SVR TSRA. HREF and its CAM members continue to be in good agreement on the evolution, track and timing of this convective complex, expected to impact the Wcent Mtns and Laurel Highlands of PA late this afternoon/early this evening, and the rest of the NW and NCENT Mtns this evening. Basin average rainfall later today/this evening will range from 1 to 5 tenths of an inch, through a few locations could see up to one inch where two or more TSRA train over the same location. Temps are on track to reach highs in the upper 70s to low 80s across the Northern and Western Mtns and mid to upper 80s throughout the Central and Southern Valleys. There is a small chc for severe gusts late this aftn and early tonight. The shear is moderate (~40kts) and there appears to be a short window of time when DCAPE of 500-800J/kg may be tapped over the NW half/third to half of the CWA. SPC MRGL risk is over the location of the best Westerly (0-3KM) and WSW deep layer 0-6KM) shear. The convection wanes/moves northeast of the CWA by shortly after midnight, followed by partial clear and areas of fog/haze late. Fog may not be as noticeable/widespread tonight despite similar dewpoints depending on the coverage of the rainfall earlier in the night. Clouds may remain in the NW until morning, as well. Mins should be in the 60s again. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... Sfc dewpoints (in the 60s) and humidity remain quite high on Tuesday as the cold front slows/dissipates over the CWA. Widespread and deep convection will be a difficult task for the atmosphere to accomplish on Tuesday. Vertical shear is weaker and the air aloft will be drier, especially across the NW in the afternoon. Concurrently, forcing in the form of a decent shortwave trough aloft and weak cold front are moving through. Will maintain PoPs for Tuesday right around 30 percent, though the potential is there for the vast majority of Central and NW PA to stay almost entirely rain-free. The best chc for a SHRA/TSRA should be across the Lower Susq late in the day as the aforementioned cold front approaches that area near peak heating. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... A front will slide east of the Commonwealth Tuesday night into Wednesday, which will result in slightly cooler temperatures and, more noticeably, lower dewpoints. After a persistent stretch of dewpoints in the upper 60s to low 70s, more comfortable dewpoints will be refreshing. With high pressure building in behind the front, most of the area will stay dry on Wednesday with only a slight chance of showers along the Mason- Dixon Line closer to the boundary that will stall out over the DelMarVa region. Another upper-level trough will dig into the Great Lakes on Thursday. At the surface, southerly flow will develop and bring a return to muggier weather along with scattered showers and thunderstorms. The main concern will be the potential for some flash flooding as many locations across the region are very vulnerable to rainfall. Flash flood guidance is as low as 0.5 inches in an hour in northeast PA and generally 1.5 to 2 inches in an hour across all but southeast PA. As such, there is currently a Slight Risk of Excessive Rainfall from WPC for a majority of Central PA. This are will be tuned in the coming days as amounts and locations come into better focus. By Friday, morning showers will give way to an improving day after a front passes through the area. The weekend weather looks nicer, with building sfc high pressure bringing near to slightly below normal temperatures and lower dewpoints. With the upper-level trough remaining overhead, cold temperatures aloft could keep at least a slight chance for afternoon showers and perhaps a stray storm on Saturday and Sunday. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... An extensive plume of wildfire smoke originating in Southwestern Canada will cover Central PA and Susq Valley airfields this afternoon and tonight with VSBYS in the 3-4SM MVFR range in many locations. Showers and thunderstorms will develop across/advect NE into the Laurel Highlands and Western Mtns of PA late this afternoon/evening and will bring the potential for some brief restrictions. Any rain looks to hold off across the southeast until after 00Z Tuesday. Outlook... tonight-Fri...Sct-numerous TSRA mainly across the Central and North Central Mtns of PA tonight and again on Thursday. Otherwise, VFR to MVFR in periods of smoke and/or haze, that was being transported all the way from Southwestern Canada. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && SYNOPSIS...Lambert NEAR TERM...Lambert SHORT TERM...Lambert LONG TERM...Evanego/Banghoff AVIATION...Lambert
Hazardous Weather Outlook National Weather Service State College PA 1101 AM EDT Mon Jul 17 2023 PAZ004>006-010>012-017>019-024-025-033-034-037-041-042-045-046- 181515- Warren-McKean-Potter-Elk-Cameron-Northern Clinton-Clearfield- Northern Centre-Southern Centre-Cambria-Blair-Somerset-Bedford-Tioga- Northern Lycoming-Sullivan-Southern Clinton-Southern Lycoming- 1101 AM EDT Mon Jul 17 2023 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...This afternoon and tonight. Strong thunderstorms with gusty winds and briefly heavy rain are possible late this afternoon and early tonight. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Thunderstorms with heavy rain are possible on Thursday, and may lead to poor drainage and small stream flooding in some locations. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather. PAZ026>028-035-036-049>053-056>059-063>066-181515- Huntingdon-Mifflin-Juniata-Fulton-Franklin-Union-Snyder-Montour- Northumberland-Columbia-Perry-Dauphin-Schuylkill-Lebanon-Cumberland- Adams-York-Lancaster- 1101 AM EDT Mon Jul 17 2023 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...This afternoon and tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Thunderstorms with heavy rain are possible on Thursday, and may lead to poor drainage and small stream flooding in some locations. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. Lambert
Special Weather Statement
National Weather Service State College PA
551 PM EDT Mon Jul 17 2023
PAZ019-027-028-045-049-050-172245-
Southern Clinton PA-Union PA-Juniata PA-Mifflin PA-Snyder PA-
Southern Centre PA-
551 PM EDT Mon Jul 17 2023
...STRONG THUNDERSTORMS WILL IMPACT NORTHEASTERN MIFFLIN...
SOUTHEASTERN CENTRE...NORTH CENTRAL JUNIATA...WESTERN SNYDER...
SOUTHWESTERN UNION AND SOUTHEASTERN CLINTON COUNTIES THROUGH 645 PM
EDT...
At 551 PM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from 13 miles east of Bellefonte to Lewistown.
Movement was northeast at 20 mph.
HAZARD...Wind gusts up to 50 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation
possible.
Locations impacted include...
Lewistown, Carroll, Woodward, Burnham, Highland Park, McClure,
Millheim, Beaver Springs, Aaronsburg, Rebersburg, Coburn,
Troxelville, Madisonburg, Alfarata, Weikert, R.B. Winter State Park,
Snyder-Middleswart State Park, Reeds Gap State Park, Belltown and
Laurelton Center.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
If boating or fishing on or near an area lake, get out of the water
and move indoors or inside a vehicle. Remember, lightning can strike
out to 10 miles from the parent thunderstorm. If you can hear
thunder, you are close enough to be struck by lightning. Move to
safe shelter now! Do not be caught on the water in a thunderstorm.
&&
LAT...LON 4116 7727 4108 7718 4092 7711 4071 7713
4054 7758 4065 7757 4073 7752 4093 7759
TIME...MOT...LOC 2151Z 234DEG 18KT 4094 7752 4083 7741 4072 7742 4055
7755
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH
LambertSpecial Weather Statement
National Weather Service State College PA
600 PM EDT Mon Jul 17 2023
PAZ012-018-172245-
Northern Centre PA-Northern Clinton PA-
600 PM EDT Mon Jul 17 2023
...A STRONG THUNDERSTORM WILL IMPACT NORTH CENTRAL CENTRE AND
NORTHWESTERN CLINTON COUNTIES THROUGH 645 PM EDT...
At 559 PM EDT, Doppler radar was tracking a strong thunderstorm 21
miles north of Bellefonte, moving northeast at 25 mph.
HAZARD...Wind gusts of 50 to 55 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation
possible.
Locations impacted include...
Keating, Renovo, South Renovo, Westport, Glen Union and Hyner.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.
&&
LAT...LON 4145 7759 4144 7760 4144 7758 4138 7754
4137 7754 4134 7748 4131 7747 4129 7745
4111 7785 4114 7794 4121 7800 4148 7767
4148 7764
TIME...MOT...LOC 2159Z 225DEG 20KT 4121 7788
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...55 MPH
LambertSpecial Weather Statement
National Weather Service State College PA
604 PM EDT Mon Jul 17 2023
PAZ034-172230-
Bedford PA-
604 PM EDT Mon Jul 17 2023
...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN BEDFORD COUNTY
THROUGH 630 PM EDT...
At 603 PM EDT, Doppler radar was tracking a strong thunderstorm over
Bedford, moving northeast at 20 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
possible.
Locations impacted include...
Bedford, New Enterprise, Cessna, Saxton, Woodbury, Defiance and
Hopewell.
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 4010 7859 4026 7835 4026 7834 4025 7829
4029 7826 4023 7824 4017 7813 4012 7816
4009 7820 4007 7820 4006 7819 4001 7849
TIME...MOT...LOC 2203Z 242DEG 17KT 4008 7848
MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH
EvanegoSpecial Weather Statement
National Weather Service State College PA
610 PM EDT Mon Jul 17 2023
PAZ028-056-063-172300-
Perry PA-Cumberland PA-Juniata PA-
610 PM EDT Mon Jul 17 2023
...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN JUNIATA...
SOUTHWESTERN PERRY AND NORTHWESTERN CUMBERLAND COUNTIES THROUGH 700
PM EDT...
At 609 PM EDT, Doppler radar was tracking a strong thunderstorm 15
miles north of Shippensburg, moving northeast at 20 mph.
HAZARD...Wind gusts up to 50 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation
possible.
Locations impacted include...
Honey Grove, Spruce Hill, East Waterford, Colonel Denning State Park,
Loysville, Ickesburg, Shermansdale, Perulack, Big Spring State Park,
Blain, Landisburg and New Germantown.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.
&&
LAT...LON 4021 7761 4023 7761 4022 7764 4023 7765
4026 7765 4026 7767 4027 7766 4036 7770
4041 7762 4056 7727 4030 7715 4019 7758
TIME...MOT...LOC 2209Z 245DEG 16KT 4026 7758
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH
LambertSpecial Weather Statement
National Weather Service State College PA
634 PM EDT Mon Jul 17 2023
PAZ019-028-045-046-049>052-172330-
Southern Lycoming PA-Southern Clinton PA-Union PA-Northumberland PA-
Montour PA-Juniata PA-Snyder PA-Southern Centre PA-
634 PM EDT Mon Jul 17 2023
...STRONG THUNDERSTORMS WILL IMPACT NORTHUMBERLAND...EAST CENTRAL
CENTRE...NORTHEASTERN JUNIATA...SNYDER...MONTOUR...SOUTHEASTERN
LYCOMING...UNION AND SOUTHEASTERN CLINTON COUNTIES THROUGH 730 PM
EDT...
At 634 PM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from 12 miles southeast of Jersey Shore to
Mifflinburg to 18 miles southwest of Selinsgrove. Movement was east
northeast at 25 mph.
HAZARD...Wind gusts up to 50 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation
possible.
Locations impacted include...
Sunbury, Milton, Lewisburg, Selinsgrove, Danville, Montoursville,
Northumberland, Mifflinburg, Carroll, Winfield, Muncy, Watsontown,
Elysburg, Fairview-Ferndale, Hughesville, Riverside, Trevorton,
Shamokin Dam, Montgomery and Linntown.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
Persons in campgrounds should consider seeking sturdy shelter until
these storms pass.
&&
LAT...LON 4070 7660 4061 7727 4085 7723 4104 7728
4111 7719 4122 7699 4131 7677 4106 7661
4105 7657 4100 7657 4097 7653
TIME...MOT...LOC 2234Z 256DEG 23KT 4103 7717 4089 7710 4067 7717
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH
LambertSpecial Weather Statement
National Weather Service State College PA
644 PM EDT Mon Jul 17 2023
PAZ028-050-052-056-057-172330-
Perry PA-Northumberland PA-Juniata PA-Dauphin PA-Snyder PA-
644 PM EDT Mon Jul 17 2023
...STRONG THUNDERSTORMS WILL IMPACT SOUTHWESTERN NORTHUMBERLAND...
NORTHWESTERN DAUPHIN...NORTHEASTERN JUNIATA...SOUTHEASTERN SNYDER AND
PERRY COUNTIES THROUGH 730 PM EDT...
At 643 PM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from 13 miles east of Lewistown to 19 miles
northwest of Enola to near Carlisle. Movement was northeast at 30
mph.
HAZARD...Wind gusts up to 50 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation
possible.
Locations impacted include...
Linglestown, Millersburg, Marysville, Newport, Duncannon,
Elizabethville, New Bloomfield, Port Trevorton, Mexico, New Buffalo,
Loysville, Ickesburg, Meiserville, Shermansdale, Rockville,
Liverpool, Port Royal, Halifax, Dauphin and Thompsontown.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
If boating or fishing on or near an area lake or river, get out of
the water and move indoors or inside a vehicle. Remember, lightning
can strike out to 10 miles from the parent thunderstorm. If you can
hear thunder, you are close enough to be struck by lightning. Move
to safe shelter now! Do not be caught on the water in a thunderstorm.
&&
LAT...LON 4040 7737 4056 7739 4072 7681 4059 7675
4036 7679 4029 7716 4029 7724 4027 7730
TIME...MOT...LOC 2243Z 239DEG 26KT 4056 7733 4041 7726 4027 7729
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH
LambertThe State College radar (KCCX), 88 km away, was scanning. The volume nearest the first event began at 23:12 UTC.
3 thunderstorm wind. Local standard time, as filed.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires in the vicinity of Newport.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires in Watts Township.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires in the vicinity of Millersburg.
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, July 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: 1108695, 1108696, 1108698.