Rain during the morning of July 9th helped to saturate the ground, and additional thunderstorms in an anomalously high moisture environment during the early evening hours created flash flooding. Wayne and Shenango Townships in Lawrence County were particularly hard hit, with at least eight homes in these areas impacted by flooding.
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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 PBZ wrote it up.
Rain during the morning of July 9th helped to saturate the ground, and additional thunderstorms in an anomalously high moisture environment during the early evening hours created flash flooding. Wayne and Shenango Townships in Lawrence County were particularly hard hit, with at least eight homes in these areas impacted by flooding. Many roads were also impacted. An isolated instance of wind damage was also noted in Beaver 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 Pittsburgh, PA wrote its last area forecast discussion before the first event at Jul 9, 4:53 PM EST, 22 minutes earlier.
Area Forecast Discussion National Weather Service Pittsburgh PA 553 PM EDT Sun Jul 9 2023 .SYNOPSIS... Showers will taper off through this evening as low pressure shifts east of the region. Dry weather will return Monday with temperature rising above seasonal averages by Tuesday. Thunderstorm chances will increase Tuesday night through the rest of the week. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... A broken line of heavy showers and isolated thunder continues to cross the area this evening with the cold front. Generally weak forcing and a lack of strong shear have kept the severe threat to a minimum. However, 90th+ percentile PWATs and slower storm motion continue to present at least an isolated flash flooding threat. Rain rates of 4 to 6 inches per hour (over shorter time spans) have been observed with several of these deeper storms. The rain gauge at our office recorded over 0.75" in about 10-15 minutes earlier in the evening. Still, most of these storms have been moving just fast enough to preclude a flooding threat. Will continue to monitor cell mergers and potential for training storms as these cross the area through the evening hours. The only change needed for the evening update was to nudge PoPs with the latest CAM blended guidance. Otherwise, the forecast remains on track. Previous discussion... With the upper trough axis positioned over northeast Ohio and the mid- level jet shifting towards central PA, the upper Ohio River Valley will experience afternoon showers with occasional thunderstorms that diminish/shift east shortly after sunset. Forcing via weak PVA and weak surface convergence is aiding convective initiation, with enough insolation across eastern OH to northwest PA to offer modest CAPE up to 1000 J/kg. The main threat will be localized flash flooding given 90th+ percentile PWATS and slow storm motion, but weak forcing and lack of stronger shear to organize convection should keep probability of occurrence low. In addition, the lower CAPE values and lack of notable dry air aloft will help to minimize a threat for damaging wind gusts. Dry weather and subsidence will promote dry conditions overnight as the upper trough axis continues its movement east of the region. Though residual boundary layer moisture resulting in cloud cover may limit fog formation, most other ingredients are in place for morning fog development (light wind, cooling temperature, abundant surface moisture with little dry advection). && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... Surface high pressure and height rises aloft will promote dry weather and a warming trend Monday into Tuesday. Temperature will rise above the daily average by Tuesday afternoon. The first in a series of shortwaves within transient flow aloft will approach the region Tuesday afternoon and evening. Models favor the development of convection along a surface trough across the northern Great Lakes, with the potential for it dropping towards northwest PA by Tuesday night. Even if they reach portions of northwest PA into eastern OH during the overnight period, the probability favors rapid weakening as it reaches the forecast area given the more stable environment and loss of stronger jet ascent. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Wide variability in expected conditions are likely to continue into Wednesday as ensembles fluctuate between a dry, warm solution with high pressure to the southeast remaining more staunch and a cooler, stormier solution with weak shortwave passages within strengthening westerly flow (with likely notable influence from evolution of prior day's convection). A more notable pivot to a wetter and cooler period becomes more probable Thursday into the weekend as ensembles favor broad troughing across the eastern U.S. that has periodic shortwaves traversing its base and creating shower and thunderstorm chances. Variability in environmental conditions ahead of any convective period remains to cloudy to note, but the active pattern could at least offer one period with a severe and/or flood threat. && .AVIATION /22Z SUNDAY THROUGH FRIDAY/... As the cold front continues its slow march eastward, scattered showers and storms are popping up. Expect any impacts to be east of ZZV. Highest probability of an airport getting hit is LBE and DUJ before 23Z. Isolated thunder instances have prompted the mention of -TSRA mentions based on observation trends. Thunder risk will minimize beyound 00Z. VFR weather carries until the predawn hours where depending on how much clearing happens will determine if we see fog or stratus. Given the last places to clear are DUJ, LBE, and MGW, highest confidence for fog or stratus resides there. However, LBE historically sees the least amount of IFR of our airports and guidance is socking them in. Elsewhere low confidence, it could range from VFR to IFR in the 7-13Z time window. Any ceiling restrictions shall lift between 13-15Z owing to VFR and scattered cirrus. Northwest wind will be light less than 10kts. .OUTLOOK... Widespread VFR conditions are expected through Wed under high pressure. Brief MVFR/IFR weather in thunderstorms are possible Thursday. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && SYNOPSIS...Frazier NEAR TERM...Rackley/Frazier SHORT TERM...Frazier LONG TERM...Frazier AVIATION...Milcarek/McMullen
Hazardous Weather Outlook National Weather Service Pittsburgh PA 155 PM EDT Sun Jul 9 2023 OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>022-029- 031-073>078-WVZ001>004-012-021-509>514-101800- Tuscarawas-Carroll-Columbiana-Coshocton-Harrison-Jefferson OH- Muskingum-Guernsey-Belmont-Noble-Monroe-Mercer-Venango-Forest- Lawrence-Butler-Clarion-Jefferson PA-Beaver-Allegheny-Armstrong- Washington-Greene-Westmoreland-Higher Elevations of Westmoreland- Fayette-Higher Elevations of Fayette-Indiana- Higher Elevations of Indiana-Hancock-Brooke-Ohio-Marshall-Wetzel- Marion-Monongalia- Ridges of Eastern Monongalia and Northwestern Preston-Preston- Eastern Preston-Western Tucker-Eastern Tucker- 155 PM EDT Sun Jul 9 2023 This Hazardous Weather Outlook is for east central Ohio, western Pennsylvania, and northern West Virginia. .DAY ONE...This afternoon and tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Monday through Saturday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
The Pittsburgh radar (KPBZ), 48 km away, was scanning. The volume nearest the first event began at 22:15 UTC.
8 flash flood, 1 thunderstorm wind. Local standard time, as filed.
Flooding was reported along Old Princetown Road.
Union Valley Road at Old Pittsburgh Road was closed due to flooding.
Water was reported to be over Center Church Road at Hell Run. A couple of ponds overflowed and temporarily merged into one.
Portions of Upper Boyd School Road and Vinegar Valley Road were flooded.
Snake Run flooded over its banks, covering a portion of Snake Run Road.
A building near the intersection of Route 65 and Rose Stop Road was partially under water.
An apple tree was uprooted on Buseman Avenue, and a tree fell on a home on Clearview Avenue.
The entirety of Union Valley Road was closed due to flooding along McKee Run.
Three to five inches of rain fell in southwest Lawrence over a 3 hour period. At least eight homes were impacted by flooding in Wayne and Shenango Townships. Numerous roads were closed in the area and several water rescues from houses and cars were performed by local firefighters. The most significant damage in Shenango Township occurred around Union Valley, Snake Run, and Lower Boyd School Roads, the latter of which was undermined, creating damage to the asphalt. Roads impacted in Wayne Township included Shenango Stop, Union Valley, Snake Run, Chewton-West Pittsburg, Fletcher Hill, Boyd School, Lower Boyd School, Old Pittsburgh, and Union Valley Roads. McKee Run was reported to overflow its banks.
The Lawrence County Commissioners issued a disaster declaration for the entire county, with the Shenango and Wayne Township supervisors adopting similar measures for their respective municipalities.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2023Every state in 2023This day in weather historyWarnings in Pennsylvania, July 2023
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: 1121451, 1121453, 1121456, 1121458, 1121498, 1121502, 1121507, 1121512, 1127577.