Showers and thunderstorms developed ahead of a cold front on the 4th of August. Modest instability and shear, considering the earlier onset of storm activity, resulted in several wind damage reports and some hail.
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 PBZ wrote it up.
Showers and thunderstorms developed ahead of a cold front on the 4th of August. Modest instability and shear, considering the earlier onset of storm activity, resulted in several wind damage reports and some hail.
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 Pittsburgh, PA wrote its last area forecast discussion before the first event at Aug 4, 12:34 PM EST, 11 minutes earlier.
Area Forecast Discussion National Weather Service Pittsburgh PA 134 PM EDT Fri Aug 4 2017 .SYNOPSIS... A cold front will bring strong to possibly severe thunderstorms this afternoon and evening. Cooler weather for this weekend. Unsettled weather returns Monday. && .NEAR TERM /THROUGH SATURDAY/... Added severe thunderstorm watch and tweaked hourly temps and dewpoints rest on track. 12Z PIT RAOB portrays a damaging wind threat with dry mid levels and unidirectional wind in the column. DCAPE calculations are near 600jkg-1 along with delta theta-e values near 30K. Icy cores near 18KFT could be enough to get a downburst. Once temperatures climb near 80F, expect towers to grow and storms to develop. With earlier onset of storms, atmosphere won't be as juicy, however low level moisture continues to funnel into the region allowing CAPE to surpass 1000 jkg-1. The treat of tornadoes is very low but non zero. Updraft helicity in the 01-km layer off 0Z NCAR 3km supports highest chance farther north in New York. Flash flooding is possible but low given progressive nature of storms. Dewpoints will be in the mid and upper 60s allowing PWATS to climb above climo. Hourly and three hourly QPF numbers are below urban flash flood guidance, but if an area gets hit with the first line and then the second line associated with front passes over the same location we could see high water. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/... Much cooler and less humid weather are the main story in this time frame. Mid level trough axis sweeps through during the morning hours which could spawn scattered showers closer to Lake Erie so will keep low pops to account given sufficient moisture in the column with a passing trigger. Dewpoints will make it feel noticeably less humid as the are forecast in the 50s while daytime highs barely make it to 70F! Southerly winds don't give us a long reprieve of sub 60F dewpoints as they return Sunday. Mid and high clouds invade during the afternoon from south to north. There is no precipitation forecast during the daytime hours. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Highlights: - Below normal temperatures - Wet start to the work week - Quieter in the middle and late Baroclinic zone that crosses today will stall south of our region then return as a warm front Sunday night into Monday. This will spread a good slug of showers across the area during the aforementioned time frame. Along and south of the boundary PWATS surpass 1.5", but thankfully due to clouds and limited instability thunder was still kept out of the forecast. This will also cut down on rain rates and threat of flooding in areas that were hard hit a week ago and clean up efforts are ongoing. At this time, have not ruled out potential flooding given rainfall amounts between 1-2", however confidence is not high enough to include in the hazardous weather outlook. Below normal H5 heights dominate through mid week which spells below normal temps with highs only in the 70s and 60s across higher elevations. Heights build toward the end of the period allowing MaxT to return to normal numbers. With passing mid level waves showers and thunderstorms return during the peak heating hours. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... General VFR is expected until storms begin to develop this afternoon ahead of an approaching cold front. Coverage will be scattered early on...followed by a line of storms crossing late afternoon/early evening. .OUTLOOK... Restrictions are likely again with Mon low pressure. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. &&
Hazardous Weather Outlook National Weather Service Pittsburgh PA 309 AM EDT Fri Aug 4 2017 MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023- 029-031-073>076-WVZ001>004-012-021-509>514-050715- Garrett-Tuscarawas-Carroll-Columbiana-Coshocton-Harrison-Jefferson- Muskingum-Guernsey-Belmont-Noble-Monroe-Mercer-Venango-Forest- Lawrence-Butler-Clarion-Beaver-Allegheny-Armstrong-Indiana- Washington-Greene-Westmoreland-Westmoreland Ridges-Fayette- Fayette Ridges-Hancock-Brooke-Ohio-Marshall-Wetzel-Marion-Monongalia- Ridges of Eastern Monongalia and Northwestern Preston-Preston- Eastern Preston-Western Tucker-Eastern Tucker- 309 AM EDT Fri Aug 4 2017 This Hazardous Weather Outlook is for western Maryland, east central Ohio, northwest Pennsylvania, southwest Pennsylvania, west central Pennsylvania, western Pennsylvania, northern West Virginia and northern panhandle of West Virginia. .DAY ONE...Today and Tonight. Scattered severe thunderstorms are possible this afternoon and early evening with a crossing cold front. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures. 07
Special Weather Statement National Weather Service Pittsburgh PA 1220 PM EDT FRI AUG 4 2017 PAZ007-041645- Mercer- 1220 PM EDT FRI AUG 4 2017 ...A STRONG THUNDERSTORM CAPABLE OF PRODUCING SMALL HAIL AND GUSTY WIND WILL AFFECT NORTHWESTERN MERCER COUNTY... At 1219 PM EDT, a strong thunderstorm was located near Vienna Center, or 8 miles west of Sharpsville, moving northeast at 45 mph. Wind gusts up to 45 mph and small hail are possible with this storm. Locations impacted include... Greenville... Jamestown... Sheakleyville... Maurice K Goddard State Park... This includes Interstate 79 in Pennsylvania between mile markers 108 and 109. This storm may intensify, so monitor local radio or television stations for additional information and possible warnings from the National Weather Service. LAT...LON 4149 8012 4127 8052 4149 8052 TIME...MOT...LOC 1619Z 224DEG 39KT 4130 8063 Kramar
Special Weather Statement
National Weather Service Pittsburgh PA
112 PM EDT FRI AUG 4 2017
PAZ031-WVZ004-012-021-509-041745-
Greene-Marshall-Marion-Monongalia-Wetzel-
112 PM EDT FRI AUG 4 2017
...A STRONG THUNDERSTORM CAPABLE OF PRODUCING SMALL HAIL AND GUSTY
WIND WILL AFFECT SOUTHWESTERN GREENE...NORTHWESTERN MONONGALIA...
WETZEL...SOUTHEASTERN MARSHALL AND NORTHWESTERN MARION COUNTIES...
At 112 PM EDT, a strong thunderstorm was located over Pine Grove, or
8 miles southeast of New Martinsville, moving northeast at 45 mph.
Wind gusts up to 55 mph and small hail are possible with this storm.
Locations impacted include...
Cameron... Pine Grove...
Hundred... Jacksonburg...
New Freeport... Wileyville...
Big Run... Reader...
Knob Fork... Littleton...
Porters Falls... Burton...
LAT...LON 3948 8067 3947 8069 3947 8071 3949 8073
3951 8074 3953 8077 3955 8079 3956 8081
3956 8082 3958 8083 3959 8085 3960 8085
3960 8086 3988 8056 3967 8023 3946 8067
TIME...MOT...LOC 1712Z 226DEG 38KT 3957 8073
KramarPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH PA
131 PM EDT FRI AUG 04 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0120 PM TSTM WND DMG BENWOOD 40.01N 80.73W
08/04/2017 MARSHALL WV TRAINED SPOTTER
SEVERAL LARGE BRANCHES DOWN
&&
EVENT NUMBER PBZ1701963
98Special Weather Statement National Weather Service Pittsburgh PA 141 PM EDT FRI AUG 4 2017 OHZ040-041-049-050-WVZ001-041815- Jefferson-Harrison-Columbiana-Carroll-Hancock- 141 PM EDT FRI AUG 4 2017 ...A STRONG THUNDERSTORM CAPABLE OF PRODUCING GUSTY WIND WILL AFFECT NORTHEASTERN HARRISON...NORTHERN JEFFERSON...SOUTH CENTRAL COLUMBIANA...SOUTHEASTERN CARROLL AND CENTRAL HANCOCK COUNTIES... At 141 PM EDT, a strong thunderstorm was located 10 miles north of Cadiz, moving northeast at 45 mph. Wind gusts up to 45 mph are possible with this storm. Locations impacted include... Wellsville... Toronto... New Cumberland... Salineville... Jewett... Bergholz... Amsterdam... Richmond... Irondale... New Manchester... Empire... Stratton... LAT...LON 4033 8098 4045 8111 4069 8083 4050 8053 TIME...MOT...LOC 1741Z 239DEG 38KT 4042 8100 Kramar
The Pittsburgh radar (KPBZ), 67 km away, was scanning. The volume nearest the first event began at 17:44 UTC.
29 thunderstorm wind, 1 hail. Local standard time, as filed.
Local 911 reported trees down on Grange Road.
Local 911 reported trees down on Poland Rd and Grange Rd.
Local 911 reported trees down.
Local 911 reported trees down.
NWS Employee reported trees down on Lakeview Dr.
Local 911 reported trees and wires down.
The public reported a few trees down, as well as large branches and limbs.
Two large trees snapped on the CCAC Boyce Campus.
Trained spotter reported trees down at the corner of Freeport Rd and Woodbury Rd.
Trained spotter reported a large tree and wires down blocking Pry Rd.
State official reported several trees down in Natrona Heights and Harrison Twp.
Local 911 reported several trees down in Murraysville.
Local 911 reported several trees down in Lower Burrell and New Kensington.
Local 911 reported trees and wires down in Manor and Buffalo Townships.
Local 911 reported multiple trees are down in Cranberry Twp.
Local 911 reported multiple trees are down on President Rd.
Local 911 reported trees down on wires in Paint Township.
Local 911 reported numerous trees down throughout the county.
Local 911 reported trees down in the town of Brookville.
NWS employee reported trees and power poles down.
Local 911 reported numerous trees and wires down.
Local 911 reported multiple trees and poles down on Bauder Mill Rd.
Local 911 reported trees down.
Local 911 reported multiple trees down in Butler Township.
Local 911 reported trees down.
Local 911 reported several trees down.
Local 911 reported trees down.
Emergency manager reported a metal roof blown off township building.
Local 911 reported trees down.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2017Every state in 2017This day in weather historyWarnings in Pennsylvania, August 2017
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: 719666, 718212, 719667, 718198, 718215, 718214, 718245, 718244, 718246, 718217, 718218, 718219, 718220, 718221, 718223, 718224, 718228, 719668, 718229, 718230, 718168, 718237, 718238, 718239, 718240, 718241, 718242, 718248, 718243, 718250.