Heavy rain with little, if any, lightning moved along a stationary front in a tropical environment. Moisture was plentiful, with precipitable water values of over 2 inches.
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.
Heavy rain with little, if any, lightning moved along a stationary front in a tropical environment. Moisture was plentiful, with precipitable water values of over 2 inches. Rainfall totals reached levels that were 350% of flash flood guidance, with 1-hour rainfall totals approaching levels that were 350% above guidance and had a 0.5% annual occurrence probability. Allegheny County activated their EOC due to the flooding and severe weather. Numerous flooding incidents were reported, and approximately 66 water rescues were needed throughout the county. Flooding damaged a number of basement foundations. Bethel Park partially activated their EOC for massive flooding. Here, water rescues occurred in the area of the Trolley Stop Inn, with 27 persons requiring rescue. Water rescues were conducted from Scott Township to Bridgeville Borough. One female was killed in Bridgeville Borough. She left her trapped car and was swept away by flood waters. Bethel Park submitted a municipal disaster declaration.
In Westmoreland County, flash floods and heavy rains occurred throughout the Ligonier Borough, Ligonier Township, Cook Township areas of the of the Loyalhanna and Mill Creek watershed in Westmoreland County causing localized flooding, road closures, wires down, and requiring multiple water rescues to be conducted of individuals in vehicles in flooded roadways. The Ligonier Valley area in eastern Westmoreland County was especially hard hit by flooded roadways that necessitated water rescues. The Westmoreland County EOC was activated for the flooding. The Johnstown, Cambria County Fire Department Swift Water Rescue Team was dispatched to assist in Ligonier Township. Several areas in the county experienced heavy basement flooding and Cook Township had first floor flooding of a residence on Green Hollow Lane that required three occupants to be rescued from a rooftop. Four adults, two children, and one dog were evacuated from two other residences. Residential flooding occurred in the area of Snowman Lane and Blouch Lane that required a water rescue of one resident.
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 Jun 20, 1:17 PM EST, 1 hour 18 minutes earlier.
Area Forecast Discussion
National Weather Service Pittsburgh PA
217 PM EDT Wed Jun 20 2018
.SYNOPSIS...
A frontal boundary will remain in the region into the weekend
and will keep active weather in the forecast.
&&
.NEAR TERM /THROUGH TONIGHT/...
Convection will largely be focused south of I-80 through early
evening along a frontal boundary running west to east through
the forecast area.
Coverage of showers and storms will continue to increase
through the afternoon as convective temperatures are reached
through daytime heating...maintained through the evening with
the passage of a shortwave. Aforementioned frontal boundary will
transition south tonight followed by building sfc high pressure
keeping any any lingering rain focused in the ridges.
Primary concern for today is heightened flash flood risk with
plenty of moisture available for localized downpours and an
ideal setup for training of storms. With that and relatively low
flash flood guidance values in consideration...opted to issue a
Flash Flood Watch through mid-evening.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Thursday will be largely dry as weak shortwave ridging
transitions over the forecast area. Temperatures will be very
close to normal for this time of year...and winds will be
light.
Precipitation chances will increase Thursday night and Friday as
a warm front approaches the region ahead of a deepening midwest
trough. Cloud cover may limit heating a bit more on Fri, with
temps in the 70s slightly below seasonal average. Surface based
convection looks unlikely based off model soundings but kept
a slight chance mention for storms as there looks to be some
elevated instability.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A strong low pressure system in the Central Plains will approach
the Great Lakes Region Fri night and Sat, with showers and
storms expected as it crosses. Given the expected negative tilt
of the system and strong forcing for ascent, the potential for
damaging wind gusts will need to be monitored despite the
less favorable timing of the sfc trough passage.
A subsequent shortwave trough could spell additional rain
chances on Sun before high pressure builds into the region on
Mon and Tue and erodes much of the low-level moisture.
Seasonable temperatures should continue into next week.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
Primarily VFR conditions will carry through the evening, but
increasing showers and thunderstorms will result in temporary
restrictions south of I-80. The surface low will shift to our east
tonight and thunderstorms are expected to diminish near midnight.
Low-level moisture wrapping around the back of the low will result
in additional restrictions overnight into early Thursday. Expecting
a mix of IFR and MVFR ceilings along the eastern periphery,
persisting longest over LBE/MGW. Gradual improvement is expected
into Thursday morning as drier air moves in from the north.
Light and variable winds could be interrupted by gusts in some of
the stronger thunderstorms this evening. Light nne winds will
establish Thursday morning.
OUTLOOK...
A brief respite on Thursday will be followed by periodic
restrictions into the weekend as the front wavers across the OH
Valley region.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...Flash Flood Watch until 10 PM EDT this evening for MDZ001.
OH...None.
PA...Flash Flood Watch until 10 PM EDT this evening for PAZ021-029-
031-073>076.
WV...Flash Flood Watch until 10 PM EDT this evening for WVZ002>004-
012-021-509>512.
&&Hazardous Weather Outlook National Weather Service Pittsburgh PA 1131 AM EDT Wed Jun 20 2018 OHZ039>041-048-057-058-068-211545- Tuscarawas-Carroll-Columbiana-Coshocton-Muskingum-Guernsey-Noble- 1131 AM EDT Wed Jun 20 2018 This Hazardous Weather Outlook is for east central Ohio. .DAY ONE...This Afternoon and Tonight. Locally heavy rainfall is expected this afternoon along a slow- moving front and could lead to localized flash flooding. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. The chance of hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. PAZ007>009-013-015-016-211545- Mercer-Venango-Forest-Lawrence-Clarion-Jefferson- 1131 AM EDT Wed Jun 20 2018 This Hazardous Weather Outlook is for northwest Pennsylvania, west central Pennsylvania and western Pennsylvania. .DAY ONE...This Afternoon and Tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. The chance of hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. OHZ049-050-059-069-PAZ014-020-022-023-WVZ001-513-514-211545- Harrison-Jefferson-Belmont-Monroe-Butler-Beaver-Armstrong-Indiana- Hancock-Western Tucker-Eastern Tucker- 1131 AM EDT Wed Jun 20 2018 This Hazardous Weather Outlook is for east central Ohio, west central Pennsylvania, western Pennsylvania and northern West Virginia. .DAY ONE...This Afternoon and Tonight. Thunderstorms are expected this afternoon along a slow-moving front. Some storms could produce flash flooding and gusty wind. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. The chance of hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. MDZ001-PAZ021-029-031-073>076-WVZ002>004-012-021-509>512-211545- Garrett-Allegheny-Washington-Greene-Westmoreland-Westmoreland Ridges- Fayette-Fayette Ridges-Brooke-Ohio-Marshall-Wetzel-Marion-Monongalia- Ridges of Eastern Monongalia and Northwestern Preston-Preston- Eastern Preston- 1131 AM EDT Wed Jun 20 2018 ...FLASH FLOOD WATCH IN EFFECT UNTIL 10 PM EDT THIS EVENING... This Hazardous Weather Outlook is for western Maryland, southwest Pennsylvania, northern West Virginia and northern panhandle of West Virginia. .DAY ONE...This Afternoon and Tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Flash Flood Watch. Thunderstorms are expected this afternoon along a slow-moving front. Some storms could produce flash flooding and gusty wind. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. The chance of hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
The Pittsburgh radar (KPBZ), 75 km away, was scanning. The volume nearest the first event began at 19:35 UTC.
18 flash flood, 1 heavy rain. Local standard time, as filed.
The 911 Call Center reported a number of roads in the city of Latrobe have been flooded.
The 911 call center reports that a number of roads have been flooded in the city of Derry.
The 911 Call Center reported that Campbells Run is overflowing its banks and flooding nearby roadways (including Campbells Run Road).
The 911 Call Center has reported that the bottom of Mahoney Road, near Cliff Mine Road, is completely closed due to flooding.
The county 911 Call Center reported residential flooding. Loyalhanna Creek is out of its banks. Many water rescues had to be performed; in some homes residents had to be rescued from their roof. The Loyalhanna Creek at Kingston, PA gage rose from 3ft to 11.7ft (crest) in roughly 10 hours.
A number of basements and roads have been flooded northwest/southeast of Uniontown near US-40. Several roads flooded and closed in the city of Uniontown.
The 911 call center reported that the 1000 block of Washington Avenue has six vehicles stuck in rising flood waters. The Department of Transportation reports that US22 in both directions at exit East I-376/US22 is flooding.
The 911 Call Center has reported that Saw Mill Run Boulevard (Outbound) is closed from I-376 to Bausman Street due to flooding.
The 911 Call Center reported that 8th Avenue at Waterfront Drive is closed due to flooding.
The 911 Call Center reported that the 3000 Block of Banksville Road had multiple vehicles in flood waters. Broadcast media reported flooding on Tolma Avenue with cars submerged half way.
The 911 Call Center reported that 800 Block of McNeilly Road is flooded. Also Library Road at Valley Drive is closed due to flooding.
The 911 Call Center has reported that a number of roads in southern Bethel Park have been flooded and/or impassable. This roads include: Glendale Drive, Logan Road, O'Neill Drive, Dashwood Drive (vehicle was stuck in water). Water entered the Trolley Stop Inn restaurant, cars in the parking lot were submerged (some floating); customers had to be rescued from the building. Local newspaper reports say at least 400 homes have been damaged and two homes were damaged so severely that they became uninhabitable. There was 1 direct injury; a young man was sucked into a storm drain while helping others trapped in the flood. He received a few bruises for this incident.
A NWS Employee measured 2.98 inches between 8:45pm and 10:30pm.
The 911 Call Center reported a number of roads flooded around Hickory.
The 911 Call Center reported a number of roads were flooded in Peters Township.
The 911 Call Center reported multiple roads in Hopewell Township were flooded.
The 911 Call Center reported that a female became trapped in her car on McLaughlin Run Road. She got out of her vehicle and attempted to walk home, however she was swept away by the flood waters of McLaughlin Run and carried about 2 miles downstream. Her body was found the next morning. A number of small bridges were destroyed along McLaughlin Run Road and near McMillian Road. Parked cars were sweep downstream along McLaughlin Run and were destroyed. An Outback Steakhouse had severe water damage. A state of emergency was declared in Upper St. Clair; Allegheny County officials had at least 66 swift water rescues (CBS Pittsburgh).
The 911 Call Center has reported numerous water rescues in Ligonier Township. The local Giant Eagle was surrounded by water and intersections on Route 30 were closed.
The 911 Call Center reported 2400 Block of Lebanon Church Road had a vehicle stuck in flood waters.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2018Every state in 2018This day in weather historyWarnings in Pennsylvania, June 2018
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: 770910, 770914, 771010, 770915, 771042, 771021, 771050, 770917, 771046, 771048, 771049, 770933, 771045, 770947, 770948, 770950, 770963, 771041, 771047.