Scattered storms developed across southern Pennsylvania during the afternoon and early evening hours on July 21, 2020 in a low-CAPE, and relatively modest shear environment. These storms produced sporadic wind damage as they pushed eastward across southern Pennsylvania.
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.
Scattered storms developed across southern Pennsylvania during the afternoon and early evening hours on July 21, 2020 in a low-CAPE, and relatively modest shear environment. These storms produced sporadic wind damage as they pushed eastward across southern Pennsylvania.
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 21, 10:10 AM EST, 2 hours 7 minutes earlier.
Area Forecast Discussion National Weather Service State College PA 1110 AM EDT Tue Jul 21 2020 .SYNOPSIS... A hot and humid mid-summer weather pattern will maintain the risk of scattered, mainly afternoon and evening thunderstorms through the end of the week. Some storms will be capable of strong gusty winds and locally heavy downpours. Maxes in the NW could be a notch cooler with all the cloud cover there. But, any late day sun could help them rise nicely. && .NEAR TERM /THROUGH TONIGHT/... Shortwave/vort max over far NE OH is spinning clouds and some showers into the CWA. One cluster over KPIT is already starting to spark. Pleanty of sunshine over the srn half of the fcst area will help us realize CAPE/B+ in the 1000-2000j/kg range there. The NW third will be mostly cloudy, so risk for strong convection lowest there. MRGL risk continues with effective deep shear of 25-30KT and those good CAPE numbers over the south. It's been so dry. So, even though heavy rain is possible, the steady movement of the storms should help keep the FF threat low unless there is some training of cells. Prev... A comfortable start to the day with variable clouds, temps in the 60s/70s and dewpoints in the upper 50s to low 60s. An increasingly moist (PWATs 1.5-2.0 inches) and marginally unstable airmass will reside across south central PA this afternoon beneath generally weak winds aloft. Hires models and ensemble guidance show various clusters of storms developing over this area with some focus over southwest PA into the Laurel Highlands. The convective environment should be supportive of slow-moving storms capable of locally heavy rain and gusty winds. WPC/SPC have covered most of this area with a marginal risk ERO/SWO. HREF shows showers and isolated storms drifting east/northeast across parts of CPA toward NEPA later this evening through tonight. Max temps will be a few degrees cooler than yesterday but still above average for late July. Highs is the low 90s for Harrisburg and surrounding areas will be the 14th day of 90+ this month. Max heat index should peak in the upper 90s across the lower Susq Valley. A muggy night expected with lows in the upper 60s to low 70s across the southern half of the area. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... Active period of convective weather continues through midweek with marginal to slight risk of locally damaging t-storm winds and heavy rainfall. It will also remain very warm and humid with above average temperatures and peak heat indices in the 90-100F range from the south-central ridge and valley region into the middle and lower Susq Valley. SPC increased categorical risk on D2 Wednesday to SLGT (15% wind probs) downwind of the Alleghenies where robust CAPE and marginal/modest shear values appear supportive of scattered, linear storm modes capable of producing strong to locally damaging downdraft winds. SPC introduced a marginal risk for D3 Thursday with a similar overall synoptic setup consisting of enhanced west-southwesterly flow aloft and sufficient diurnal destablization. A mainly linear storm mode should occur with strong to locally damaging winds the most likely threat. && .LONG TERM /FRIDAY THROUGH MONDAY/... A drier pattern appears likely into the weekend under building high pressure surface and aloft. The next frontal system will approach the area by early next week. Temps will remain above average and trend hotter Friday-Monday. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... A couple of light SHRA moving into the west has hurried up mentions of SHRA at BFD. Will tweak JST to mention TS soon as the heavier showers over KPIT are starting to make ltg and are nearing while cu are building up locally. Prev... A warm front lifting into PA from the south will spread scattered showers into the region today, with tsra possible across the southern half of the state. Heavier showers could be accompanied by a brief vis reduction during the afternoon across primarily southern Pa. Light wind, partial clearing and light wind could set the stage for patchy fog tonight, especially in those locations that receive rain today. Outlook... Wed...Patchy AM low cigs/fog possible. Sct PM tsra impacts possible. Thu...AM low cigs possible W Mtns. Sct PM tsra impacts possible, mainly southeast Pa. Fri-Sat...No sig wx expected. && .CLIMATE... Harrisburg tied the record high minimum temperature of 79 degrees yesterday (7/20). The previous record was in 2019. Through 7/20, the average July temperature at Harrisburg is 81.6F or +5.7 degrees above normal - ranking as the 2nd warmest on record only 0.2F behind 1999. With persistent heat/above avg temps expected through the end of the month, July 2020 has a shot at the warmest July on record. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && SYNOPSIS...Steinbugl NEAR TERM...Dangelo/Steinbugl SHORT TERM...Steinbugl LONG TERM...Gartner/Colbert AVIATION...Fitzgerald/Dangelo CLIMATE...
Hazardous Weather Outlook National Weather Service State College PA 529 AM EDT Tue Jul 21 2020 PAZ004>006-220930- Warren-McKean-Potter- 529 AM EDT Tue Jul 21 2020 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...Wednesday through Monday. Isolated strong to severe thunderstorms with gusty winds and locally heavy rain are possible Wednesday afternoon. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. PAZ010-011-017-024-033-220930- Elk-Cameron-Clearfield-Cambria-Somerset- 529 AM EDT Tue Jul 21 2020 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...Today and tonight. Slow-moving thunderstorms may produce isolated strong gusty winds and flooding this afternoon. Isolated flooding is most likely in areas that can experience rapid runoff from heavy rainfall. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. Isolated strong to severe thunderstorms with gusty winds and locally heavy rain are possible Wednesday afternoon. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather. PAZ012-037-041-042-045-046-051-053-220930- Northern Clinton-Tioga-Northern Lycoming-Sullivan-Southern Clinton- Southern Lycoming-Montour-Columbia- 529 AM EDT Tue Jul 21 2020 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...Wednesday through Monday. Scattered severe thunderstorms with damaging winds 60 mph or greater are possible Wednesday afternoon. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather. PAZ018-019-025>028-034-035-049-050-052-220930- Northern Centre-Southern Centre-Blair-Huntingdon-Mifflin-Juniata- Bedford-Fulton-Union-Snyder-Northumberland- 529 AM EDT Tue Jul 21 2020 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...Today and tonight. Slow-moving thunderstorms may produce gusty winds and localized flooding this afternoon. Localized flooding is most likely in areas that can experience rapid runoff from heavy rainfall. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. Scattered severe thunderstorms with damaging winds 60 mph or greater are possible Wednesday afternoon. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather. PAZ036-056>059-063>066-220930- Franklin-Perry-Dauphin-Schuylkill-Lebanon-Cumberland-Adams-York- Lancaster- 529 AM EDT Tue Jul 21 2020 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...Today and tonight. Slow-moving thunderstorms may produce gusty winds and localized flooding this afternoon. Localized flooding is most likely in areas that can experience rapid runoff from heavy rainfall. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. Scattered severe thunderstorms with damaging winds 60 mph or greater are possible Wednesday afternoon. Maximum heat indices around 100 degrees are probable Wednesday afternoon. Isolated strong to severe thunderstorms with gusty winds are possible Thursday afternoon. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather. MRS
Special Weather Statement
National Weather Service State College PA
1215 PM EDT Tue Jul 21 2020
PAZ033-211700-
Somerset PA-
1215 PM EDT Tue Jul 21 2020
...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN SOMERSET COUNTY
UNTIL 100 PM EDT...
At 1214 PM EDT, Doppler radar indicated a strong thunderstorm near
Friendsville, moving northeast at 20 mph.
Wind gusts of up to 55 mph are possible.
Very heavy rain is expected.
Locations impacted include...
Ursina, Mount Davis, Confluence and Addison.
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 3973 7941 3977 7938 3978 7939 3979 7938
3978 7935 3980 7937 3982 7937 3985 7942
3990 7940 3994 7937 3983 7916 3972 7916
3972 7938
TIME...MOT...LOC 1614Z 243DEG 16KT 3971 7947
DangeloSpecial Weather Statement
National Weather Service State College PA
1256 PM EDT Tue Jul 21 2020
PAZ024-211730-
Cambria PA-
1256 PM EDT Tue Jul 21 2020
...A STRONG THUNDERSTORM WILL AFFECT PARTS OF CAMBRIA COUNTY UNTIL
130 PM EDT...
At 1255 PM EDT, Doppler radar indicated a strong thunderstorm over
Belsano, moving east at 30 mph.
Wind gusts 40 to 50 mph and penny size hail are possible.
Locations impacted include...
Ebensburg, Nanty-Glo, Northern Cambria, Patton, Loretto, Hastings,
Carrolltown, Belsano, Prince Gallitzin State Park, Colver,
Vintondale, Ashville, Chest Springs and Saint Francis University.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential rainfall is also occurring with 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 4064 7885 4073 7862 4072 7854 4060 7844
4054 7848 4051 7854 4049 7854 4044 7895
TIME...MOT...LOC 1655Z 254DEG 50KT 4051 7890
Gartner/MartinSpecial Weather Statement
National Weather Service State College PA
111 PM EDT Tue Jul 21 2020
PAZ024-025-211745-
Blair PA-Cambria PA-
111 PM EDT Tue Jul 21 2020
...A STRONG THUNDERSTORM WILL AFFECT PARTS OF BLAIR AND CAMBRIA
COUNTIES UNTIL 145 PM EDT...
At 111 PM EDT, Doppler radar indicated a strong thunderstorm over St.
Michael, moving east at 25 mph.
Wind gusts 40 to 50 mph and penny size hail are possible.
Locations impacted include...
Portage, Salix-Beauty Line Park, Beaverdale-Lloydell, Lilly, South
Fork, Sidman, St. Michael, Dunlo, Ehrenfeld, Ski Gap, Spring Hill,
Summerhill, Wilmore, Cassandra, Blue Knob Ski Resort, Allegheny
Portage Railroad National Historic Site and John Murtha
Johnstown-Cambria County Airport.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential rainfall is also occurring with 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 4048 7848 4027 7848 4029 7850 4029 7853
4033 7862 4031 7864 4028 7864 4028 7865
4030 7886 4037 7886
TIME...MOT...LOC 1711Z 260DEG 23KT 4035 7875
GartnerSpecial Weather Statement National Weather Service State College PA 115 PM EDT Tue Jul 21 2020 PAZ033>035-211800- Bedford PA-Fulton PA-Somerset PA- 115 PM EDT Tue Jul 21 2020 ...STRONG THUNDERSTORMS WILL AFFECT PARTS OF BEDFORD...SOMERSET... AND FULTON COUNTIES UNTIL 200 PM EDT... At 114 PM EDT, Doppler radar indicated a strong thunderstorm near Lake Gordon, moving east at 25 mph. Wind gusts 40 to 50 mph and penny size hail are possible. Locations impacted include... Bedford, Breezewood, Berlin, Clearville, Everett, Buffalo Mills, Crystal Springs, Lake Gordon, Locust Grove, Barnes Gap, Inglesmith, Hyndman, Ellerslie, Manns Choice, Wellersburg, New Baltimore, Rainsburg and Callimont. PRECAUTIONARY/PREPAREDNESS ACTIONS... Torrential rainfall is also occurring with 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 3972 7896 4000 7893 4003 7821 3972 7821 TIME...MOT...LOC 1714Z 260DEG 23KT 3980 7861 Gartner/Dangelo
The State College radar (KCCX), 73 km away, was scanning. The volume nearest the first event began at 17:17 UTC.
16 thunderstorm wind. Local standard time, as filed.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires onto Cooney Road to the west of Cresson.
A sub-severe thunderstorm producing winds estimated near 50 mph knocked down a tree at the intersection of Johnstown Road and Baird Lane.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires on Veil Road in Scalp Level.
A severe thunderstorm producing winds estimated near 60 mph knocked down several trees onto Church Drive to the south of Windber.
A severe thunderstorm producing winds estimated near 60 mph knocked down multiple trees onto Camp Drive at Patricia Lane to the southwest of Windber.
A severe thunderstorm microburst produced straight line wind damage near the town of Ashtola, Pennsylvania, which is about 4 miles SE of Windber. Approximately 75-100 trees on private property just west of the Gallitzin State Forest and east of Crum Rd were downed by strong winds. Most of the damage was confined to an area about 100 yards wide and 500 yards long. Winds were estimated at 85-95 mph. We thank Somerset County and Ogle Township Emergency Management for providing aerial imagery for the damage analysis.
A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires across Route 522 near Back Run Road, closing the roadway to traffic.
A severe thunderstorm producing winds estimated near 60 mph knocked down multiple trees in McConnellsburg.
A severe thunderstorm producing winds estimated near 60 mph knocked down wires onto North Franklin Street in Chambersburg.
A severe thunderstorm producing winds estimated near 60 mph knocked down a tree onto a golfer, who was injured, at the Chambersburg Country Club.
A severe thunderstorm microburst produced straight line wind damage in Fayetteville, PA. Approximately 100 trees were downed by strong winds along a path approximately 700 yards long and 100 yards wide. Most of this damage occurred in a forested area alongside the road between 1640 and 1350 Woodstock Rd. In addition to this concentrated swath of damage, peripheral wind damage was scattered between Fayetteville and Chambersburg, including several isolated instances of trees down and damage to roofs of buildings. Wind in this area was estimated at 70-80 mph. A roof was ripped off a warehouse building on the 1600 block of Lincoln Highway. Another roof was partially removed from a building on the 1700 block of Lincoln Highway. A roof was partially removed from a barn and a shed was destroyed on the 2500 block of Grant Point Rd. One person was injured when a tree fell onto a person in Chambersburg. We thank the Civil Air Patrol for providing aerial imagery that was used in this damage analysis.
A severe thunderstorm producing winds estimated near 60 mph knocked down dozens of trees and damaged roofs in Chambersburg.
A severe thunderstorm producing winds estimated near 60 mph knocked down a tree onto a home on State Street in Scotland.
A severe thunderstorm producing winds estimated near 60 mph knocked down a tree at the intersection of Myers Road and Jefferson Road in Codorus Township.
A severe thunderstorm producing winds estimated near 60 mph knocked down a tree at the intersection of Ambau Road and Jefferson Road to the south of Spring Grove.
A severe thunderstorm producing winds estimated near 60 mph knocked down a tree onto Pine Street in Winterstown.
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: 911251, 911258, 911260, 911262, 911263, 902292, 911264, 911265, 911269, 911273, 902296, 911274, 911276, 911277, 911278, 911279.