Showers and thunderstorms formed along a nearly stationary boundary that crept southeastward from the Great Lakes. 6 inches and weak steering flow along the boundary led to a few areas of training thunderstorms.
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 formed along a nearly stationary boundary that crept southeastward from the Great Lakes. Precipitable water values of around 1.6 inches and weak steering flow along the boundary led to a few areas of training thunderstorms. Rainfall amounts of 1.5 to 2.5 inches on already saturated ground led a few areas of flash flooding in Brooke and Hancock Counties.
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 10, 4:49 PM EST, 30 minutes earlier.
Area Forecast Discussion National Weather Service Pittsburgh PA 549 PM EDT Fri Aug 10 2018 .SYNOPSIS... An active weather pattern through the weekend, but no day will be a wash out. A pesky upper level low pressure parked over the Ohio Valley brings scattered showers and thunderstorms mostly during the afternoon and evening hours through the middle of next week. && .NEAR TERM /THROUGH SATURDAY/... Area of showers and embedded thunderstorms continues to weaken and will do so the next 1-3 hours. The worse appears over as we transition into a stratiform rain event. No changes to forecast other than to updated hourly temperature trend. Previous discussion below... Numerous showers with embedded thunder have fired up right on cue along a surface convergence boundary. This activity will increase in coverage until about 5pm when it becomes more scattered as atmosphere becomes less stable due to rain cooled air. No diurnal trend in pops tonight given plenty of moisture in low levels and residual outflow boundaries coupled with a surface convergence zone. Still pinpointing areas south of I-76 as locations with highest percentage to see a shower overnight. High water risk is elevated through early evening for training of storms and weak steering winds. As of 2pm rain rates have not been overly high from thunderstorms, but if a location gets hit two or three times, we could see problems in low lying and more flood prone areas. Areas of fog could develop overnight if we loose nocturnal stratocu especially if a location gets a shower or storm today. Saturday will be a repeat of today given a lingering surface boundary, copious amounts of low level relative humidity, and a passing shortwave trough. The area of concern shifts a little farther south to the I-70 - US 50 corridor in West Virginia. Right now, given run of dry weather there doesn't appear to be a flash flooding concern. Likely pops are predicted in the aforementioned region. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... Overall little if any change in the forecast with respect to pops. Upper level low pressure remains camped over the Ohio Valley. Pops take on a more diurnal trend Saturday night onward. && .LONG TERM /MONDAY THROUGH FRIDAY/... Highlights: - Redundant Forecast afternoon/evening pop up storms - Temperatures just below normal - Strong front Thursday Extended range ensembles remain in lock step for this time frame as a upper level low creates daily precipitation chances across the region. As daytime heating destabilizes the atmosphere, showers and isolated storms will pop up during the afternoon and evening hours. Monday and Tuesday in the mountains appear to be the day with the greatest coverage as it coincides with the passing of a stronger shortwaves. Confidence not as high farther west as southeast flow sets up and that may protect the windward side of the Appalachians for a couple of days. A synoptic cold front is still forecast to cross Thursday afternoon evening. Depending how much sunshine is observed during the day and if the timing holds, it could present a severe weather risk. The associated mid level cyclone will pass north of Lake Erie which is where most of the upper level dynamics reside, therefore confidence remains below 30% for inclusion into hazardous weather outlook. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/... Scattered showers and thunderstorms will continue to increase in coverage through the evening as a shortwave helps push a boundary, that is currently bisecting the region, to the south. Expect brief restrictions to MVFR and IFR as thunderstorms pass over a terminal, with greatest confidence that this will occur at PIT, AGC, LBE, and HLG. Loss of diurnal heating should decrease shra/tsra coverage overnight, though the lingering boundary supports the continuation of VCSH with some possible restrictions in fog as a result of this afternoon/evenings rainfall. Fog coverage will be dependent on how much clearing there is, but opted to at least make mention of this at most sites overnight. OUTLOOK... Brief restrictions are possible through Tue, especially in the aftn/eve, in convection with a persistent upper trough across the region. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. &&
Hazardous Weather Outlook National Weather Service Pittsburgh PA 1223 PM EDT Fri Aug 10 2018 PAZ014-020>023-029-031-073>076-WVZ001>004-509>512-111630- Butler-Beaver-Allegheny-Armstrong-Indiana-Washington-Greene- Westmoreland-Westmoreland Ridges-Fayette-Fayette Ridges-Hancock- Brooke-Ohio-Marshall-Monongalia- Ridges of Eastern Monongalia and Northwestern Preston-Preston- Eastern Preston- 1223 PM EDT Fri Aug 10 2018 This Hazardous Weather Outlook is for southwest Pennsylvania, west central Pennsylvania, western Pennsylvania, northern West Virginia and northern panhandle of West Virginia. .DAY ONE...This Afternoon and Tonight. Showers and a few thunderstorms are expected today, with the greatest concentration expected during the afternoon and evening. Some of the thunderstorms could produce locally heavy rainfall, and localized flash flooding is possible if a location is hit by multiple bouts of heavy rain. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013-015-016- WVZ012-021-513-514-111630- Garrett-Tuscarawas-Carroll-Columbiana-Coshocton-Harrison-Jefferson- Muskingum-Guernsey-Belmont-Noble-Monroe-Mercer-Venango-Forest- Lawrence-Clarion-Wetzel-Marion-Western Tucker-Eastern Tucker- 1223 PM EDT Fri Aug 10 2018 This Hazardous Weather Outlook is for western Maryland, east central Ohio, northwest Pennsylvania, west central Pennsylvania, western Pennsylvania and northern West Virginia. .DAY ONE...This Afternoon and Tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH PA
542 PM EDT FRI AUG 10 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0535 PM FLASH FLOOD ATLASBURG 40.34N 80.38W
08/10/2018 WASHINGTON PA EMERGENCY MNGR
ATLASBURG POST OFFICE 1620 SMITH TOWNSHIP STATE ROAD
FLOODED.
&&
EVENT NUMBER PBZ1803352PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH PA
544 PM EDT FRI AUG 10 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0535 PM FLASH FLOOD 1 NW HENDERSONVILLE 40.30N 80.16W
08/10/2018 WASHINGTON PA EMERGENCY MNGR
ROADWAY FLOODED AT 123 CECIL HENDRISON ROAD IN CECIL.
&&
EVENT NUMBER PBZ1803353PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH PA
545 PM EDT FRI AUG 10 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0515 PM FLASH FLOOD 1 WNW STUDA 40.31N 80.47W
08/10/2018 WASHINGTON PA EMERGENCY MNGR
FLOODING REPORTED AT 63 COLE SCHOOOL RAOD IN JEFFERSON
TOWNSHIP.
&&
EVENT NUMBER PBZ1803354PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE PITTSBURGH PA
548 PM EDT FRI AUG 10 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0500 PM FLASH FLOOD BELLEVUE 40.17N 80.25W
08/10/2018 WASHINGTON PA EMERGENCY MNGR
JEFFERSON AVENUE AND WEST MAIDEN STREETS ARE CLOSED DUE
TO FLOODING.
&&
CORRECTED REMARKS
EVENT NUMBER PBZ1803351PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE PITTSBURGH PA
549 PM EDT FRI AUG 10 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0515 PM FLASH FLOOD 1 WNW STUDA 40.31N 80.47W
08/10/2018 WASHINGTON PA EMERGENCY MNGR
FLOODING REPORTED AT 63 COLE SCHOOOL ROAD IN JEFFERSON
TOWNSHIP.
&&
CORRECTED REMARKS
EVENT NUMBER PBZ1803354PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH PA
617 PM EDT FRI AUG 10 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0616 PM HEAVY RAIN CANONSBURG 40.26N 80.19W
08/10/2018 M1.70 INCH WASHINGTON PA NWS EMPLOYEE
FELL IN 1HR AND 40 MINS
&&
EVENT NUMBER PBZ1803355
98The Pittsburgh radar (KPBZ), 33 km away, was scanning. The volume nearest the first event began at 22:17 UTC.
2 flash flood, 1 heavy rain. Local standard time, as filed.
County 911 officials reported that Harmon Creek was flooding onto Harmon Creek Road.
County 911 officials reported flooding at Main Street and Freedom Way in downtown Weirton. US Route 22 was also partially flooded due to Kings Creeks overflowing its banks.
A trained spotter reported a rainfall total of 3.70 inches for the day.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in West Virginia in 2018Every state in 2018This day in weather historyWarnings in West Virginia, August 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: 779400, 779401, 779404.