Showers and storms developed over the Laurel Highlands of southwestern Pennsylvania during the afternoon hours of July 16, 2020, in a moderate CAPE/moderate shear environment in the vicinity of a warm frontal boundary. One of these storms produced wind damage in the vicinity of Johnstown in Cambria County.
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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.
Showers and storms developed over the Laurel Highlands of southwestern Pennsylvania during the afternoon hours of July 16, 2020, in a moderate CAPE/moderate shear environment in the vicinity of a warm frontal boundary. One of these storms produced wind damage in the vicinity of Johnstown in Cambria 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 16, 2:10 PM EST, 5 minutes earlier.
Area Forecast Discussion National Weather Service State College PA 310 PM EDT Thu Jul 16 2020 .SYNOPSIS... The summertime pattern will turn increasingly more humid through Friday with scattered showers and thunderstorms. A few storms could reach severe limits across the Northwest Alleghenies and Laurel Highlands this afternoon and evening. Temperatures will trend hotter over the weekend with the potential for excessive heat conditions into early next week across parts of south central and southeastern PA. && .NEAR TERM /UNTIL 9 PM THIS EVENING/... *Severe Thunderstorm Watch #378 issued for the western Alleghenies until 01 UTC (9 PM EDT). Previous discussion... Minor changes to near term fcst with the mid- late morning update. Severe storm risk (5% tornado prob) appears confined to the western periphery of the CWA with low clouds maintaining stability east of the Alleghenies. WPC recently highlighted NW PA with a MPD for locally heavy rain and isolated short-term flooding risk ramping up in the 18-21Z timeframe. Visible sat loop shows plenty of cloud breaks from eastern OH into western PA. Moisture advection/convergent inflow at 850mb out of the southwest and continued surface heating should support moderate buoyancy ahead of weak cold front moving into western OH. HREF fcst MLCAPE and deep shear profiles will be supportive of supercells and accompanying threat of dmg winds and isolated large hail. High dewpoints near 70F (lower LCLs) and mean SRH 200-300 m2/s2 near the edge of the unstable warm sector airmass (PBZ/CTP CWA boundary) continues to suggest a few tornadoes may be possible. Previous discussion... LLVL pressure gradient tightens ahead of slowly weakening low pressure that will be moving ENE from the Ohio Valley to the Lake Erie this afternoon and early this evening. Minor concern regarding the amount and intensity of TSRA this afternoon surrounds the degree of cirrus from Wednesday's upstream convection. Several hours of sunshine and typical diurnal mixing will likely erode at least some of cirrus/cirrostratus layer leaving plenty of heating to boost sfc based cape to between 1500-2000 j/kg. In addition, RAP shows impressive llvl shear and a broad loop hodograph at NW PA grid points. This will be highly supportive of discrete supercells for up to several hours after the onset as 0-1KM EHIs increase to between 3-4 m2/s2 between 18-23Z near and to the west of the RT 219 corridor from KBFD to KJST. This area of the CWA remains in SPC's Day 1 SLGT Risk for SVR, with an elevated...5% chc of tornado occurrence within 25 miles of a given point. Convection will be in the form of isolated to sctd late afternoon/evening showers and TSRA across the eastern third of the state with peak intensity of the strongest storms below severe levels. There is also the potential for isolated instances of flooding this afternoon/evening across the northwest mountains, as plume of anomalous PWs combine with instability and lift near front to support torrential downpours. Last few runs of the HREFV2 indicates a decent chance of spot 3-6 hour amounts of 3+ inches across the northwest counties. SSE sfc winds will likely gust into the 20-25 mph range at times during the late morning and afternoon hours. Temps are quite mild and starting out in the upper 60s to low 70s at daybreak and will warm into the mid 70s acrs the northern mtns to between 80 and 85 in the Central and Southern valleys. && .SHORT TERM /9 PM THIS EVENING THROUGH 6 PM FRIDAY/... Scattered strong to severe storms remain possible early this evening across western PA. Lows trend warmer/muggy Thursday night with a corridor of showers likely persisting across the northern part of the forecast area as the weak frontal boundary trailing south from the weakening low moving ENE across Lake Erie and the Niagara frontier, drifts east across the NW Mtns well after midnight. Weak frontal boundary sagging slowly SE across the CWA will focus sctd-numerous mainly afternoon and early evening showers/TSRA across the SE half of PA Friday afternoon. Loss of significant llvl and deep-layer shear will mean weaker/mainly pulse or small multi-cell clusters of TSRA Friday afternoon and evening. Highs Friday afternoon will be 3-5F warmer than today (Thu). && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... Not a lot of change to this part of the forecast package. Looking at most of the weekend to be dry, but with rather high dewpoints across the southeast, not hard to have an isolated shower or storm. The big story will be the heat and humidity. Current dewpoints support advisory type heat at times Sunday into Tuesday, with some potential to touch warning level heat in the southeast, especially on Monday. No sign of any large scale changes anytime soon. Current trends will likely push us into the top 10 warmest July's on record. Welcome to summer. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... MVFR cigs hanging touch across the eastern 2/3 of CPA airspace at 18Z Thu. Cigs may improve to low VFR just above 3kft AGL but trend lower again into tonight (MVFR). Scattered showers and t-storms will be confined to the western airspace through this evening before decreasing in coverage drifting to the east later tonight. Widespread MVFR cigs likely to start the day on Friday with gradual improvement through the afternoon. The southeast 1/2 airspace is most likely to see a few showers/tstm Friday afternoon. Outlook... Sat...Patchy AM fog possible, otherwise VFR. Sun...Mainly VFR. Sct showers/t-storms west late aftn-night. Mon-Tue...Mainly VFR. Sct PM showers/t-storms. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && SYNOPSIS...Steinbugl NEAR TERM...Steinbugl SHORT TERM...Lambert/Fitzgerald/Steinbugl LONG TERM...Martin AVIATION...Steinbugl
Hazardous Weather Outlook National Weather Service State College PA 126 PM EDT Thu Jul 16 2020 PAZ004>006-010-011-017-024-033-171730- Warren-McKean-Potter-Elk-Cameron-Clearfield-Cambria-Somerset- 126 PM EDT Thu Jul 16 2020 ...SEVERE THUNDERSTORM WATCH 378 IN EFFECT UNTIL 9 PM EDT THIS EVENING... This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...This afternoon and 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. Localized flooding is also possible primarily in areas that can experience rapid runoff from heavy rainfall. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather. PAZ012-018-019-025>027-034-035-037-041-045-046-171730- Northern Clinton-Northern Centre-Southern Centre-Blair-Huntingdon- Mifflin-Bedford-Fulton-Tioga-Northern Lycoming-Southern Clinton- Southern Lycoming- 126 PM EDT Thu Jul 16 2020 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...This afternoon and tonight. Isolated strong thunderstorms with gusty winds are possible this afternoon and early this evening. Localized flooding is also possible primarily in areas that can experience rapid runoff from heavy rainfall. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather. PAZ042-171730- Sullivan- 126 PM EDT Thu Jul 16 2020 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...Friday through Wednesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. PAZ028-036-049>053-056>059-063>066-171730- Juniata-Franklin-Union-Snyder-Montour-Northumberland-Columbia-Perry- Dauphin-Schuylkill-Lebanon-Cumberland-Adams-York-Lancaster- 126 PM EDT Thu Jul 16 2020 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...This afternoon and tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. There will be an increased risk of heat-related illnesses across the middle and lower Susquehanna Valley region Saturday through Tuesday. Heat indices in excess of 100 degrees are possible and could prompt heat advisories for portions of the region. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather. MRS
Special Weather Statement
National Weather Service State College PA
234 PM EDT Thu Jul 16 2020
PAZ033-161900-
Somerset PA-
234 PM EDT Thu Jul 16 2020
...A STRONG THUNDERSTORM WILL AFFECT PARTS OF SOMERSET COUNTY UNTIL
300 PM EDT...
At 233 PM EDT, Doppler radar indicated a strong thunderstorm near New
Centerville, moving northeast at 35 mph.
Wind gusts of up to 55 mph and half inch hail are possible.
Locations impacted include...
Somerset, Friedens, Boswell, Acosta, New Centerville, Seven Springs,
Rockwood, Jennerstown, Stoystown, Casselman and Laurel Mountain State
Park.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential rainfall is also occurring ahead of this storm, and may
lead to localized flooding. Do not drive your vehicle through
flooded roadways.
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 4009 7926 4010 7923 4012 7921 4011 7919
4012 7917 4016 7916 4018 7913 4020 7912
4021 7911 4009 7889 3986 7920 3993 7938
TIME...MOT...LOC 1833Z 221DEG 31KT 4000 7921
ColbertSpecial Weather Statement
National Weather Service State College PA
250 PM EDT Thu Jul 16 2020
PAZ024-033-161915-
Somerset PA-Cambria PA-
250 PM EDT Thu Jul 16 2020
...A STRONG THUNDERSTORM WILL AFFECT PARTS OF SOMERSET AND CAMBRIA
COUNTIES UNTIL 315 PM EDT...
At 250 PM EDT, Doppler radar indicated a strong thunderstorm over
Davidsville, moving northeast at 40 mph.
Wind gusts of up to 55 mph and half inch hail are possible.
Locations impacted include...
Johnstown, Westmont, Windber, Belmont, Nanty-Glo, Portage, Geistown,
Southmont, Vinco, Boswell, Dale, East Conemaugh, Salix-Beauty Line
Park, Davidsville, Beaverdale-Lloydell, Paint, Jerome, South Fork,
Scalp Level and Sidman.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 4036 7900 4052 7891 4037 7856 4035 7860
4033 7862 4012 7893 4019 7913
TIME...MOT...LOC 1850Z 224DEG 36KT 4025 7895
ColbertSpecial Weather Statement
National Weather Service State College PA
315 PM EDT Thu Jul 16 2020
PAZ033-034-162000-
Bedford PA-Somerset PA-
315 PM EDT Thu Jul 16 2020
...STRONG THUNDERSTORMS WILL AFFECT PARTS OF BEDFORD AND SOMERSET
COUNTIES UNTIL 400 PM EDT...
At 314 PM EDT, Doppler radar indicated a cluster of strong
thunderstorms extending from near Davidsville to near Bel Air.
Movement was northeast at 20 mph.
Wind gusts 40 to 50 mph and half inch hail are possible.
Locations impacted include...
Somerset, Windber, Meyersdale, Berlin, Friedens, Boswell,
Davidsville, Central City, Jerome, Buffalo Mills, Acosta, New
Centerville, Blue Knob State Park, Lake Gordon, Ogletown, Mount
Davis, Hyndman, Rockwood, Salisbury and Hooversville.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 3972 7912 3985 7931 4021 7899 4026 7890
4024 7886 4024 7866 4026 7864 4028 7865
4033 7862 4027 7857 4022 7856 3972 7853
TIME...MOT...LOC 1914Z 244DEG 17KT 4017 7890 3962 7885
ColbertThe State College radar (KCCX), 100 km away, was scanning. The volume nearest the first event began at 19:16 UTC.
2 thunderstorm wind. Local standard time, as filed.
A severe thunderstorm producing winds estimated near 60 mph knocked down a tree onto Singer Hill Road near Killiwatt Street east of Johsntown.
A severe thunderstorm producing winds estimated near 60 mph knocked down a tree onto a residence in Southmont.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2020Every state in 2020This day in weather historyWarnings in Pennsylvania, July 2020
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: 909442, 909443.