A mid-level shortwave trough moved across the northern Great Lakes with a belt of stronger flow moving through the southern Great Lakes. Scattered thunderstorms|developed through midday into the afternoon.
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.
A mid-level shortwave trough moved across the northern Great Lakes with a belt of stronger flow moving through the southern Great Lakes. Scattered thunderstorms|developed through midday into the afternoon. Forecast soundings showed some low-level hodograph curvature. Supercells evolved ahead of the cold front and create a large hail and tornado threat.
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 12, 1:49 PM EST, 51 minutes earlier.
Area Forecast Discussion
National Weather Service Pittsburgh PA
249 PM EDT Sat Aug 12 2023
.SYNOPSIS...
Severe thunderstorms with potential for large hail, damaging
winds, heavy rainfall, and isolated tornadoes are expected ahead
of a cold front this evening. A brief respite is expected Sunday
before more thunderstorms and potential heavy rainfall and
damaging winds arrive Monday.
&&
.NEAR TERM /THROUGH TONIGHT/...
Diurnal heating has been sufficient to generate moderate
instability with MLCAPE around 2,000 j/kg across most of the
forecast area. 0-6km shear is around 40 knots and could further
increase to about 50 knots as 500 mb flow increases late this
afternoon. 850 mb wind max of 25 knots shown to move across area
by 00z.
LCL heights are favorable for strong tornadoes, but current
0-1km shear of just 10 knots is not. Slight increase of 850 mb
winds early this evening will boost the low level shear some.
STP does increase to about 1 early this evening so a few
tornadoes are certainly possible. Large hail is the primary
threat with supercells early on, transitioning to damaging winds
as cold pools become better developed.
Swath of heavy rain last night with very low flash flood
guidance values has concern for flooding as well. Normally in
supercell environments heavy rain is brief and transient but
with saturated soils and several rounds of storm, put up a flood
watch in swath of middle of forecast area that closely matches
last nights swath of 2-3 inches of rain.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
The potential for severe weather and heavy rainfall returns
Monday afternoon/evening as an upper-lvl trough strengthens over
the Midwest and advances into the Ohio River Valley. Models
have been consistent with this next disturbance, and are showing
impressive 100 meter 12 hour 500mb height falls by Monday night
over Ohio. Hence the Storm Prediction Center (SPC) including a
"Slight" Risk for much of area, as does WPC for heavy rainfall.
If the timing of this system remains promising in the late
afternoon/evening storms have the potential to tap into strong
vertical shear values aloft. Damaging winds will likely be the
main threat.
Instability is a bit more questionable for this system but
moisture is not. Guidance has been consistent at bringing strong
deep moisture transport and precipitable water values of 2.00 to
2.25". Given recent heavy rainfalls and the rain from the
ongoing storms tonight, antecedent conditions are becoming more
favorable for flash flooding. Widespread 1-2" rainfall with the
usual locally higher amounts are expected.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Short wave ridging and decent height rises are expected to bring
relatively quiet weather Tuesday and Wednesday.
Another trough and weak surface cold front is expected to
approach the region Thursday and Friday, returning slight/low
chances for showers.
Focus then turns to the strong upper High approaching 600 dm
forecast to build into middle MS river valley Saturday with
temperatures jumping above normal. The recent rainfall and
warming temperatures suggest hot and muggy conditions by next
weekend and the threat for 90F+ late summer weather.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
Widespread convective activity is expected during the afternoon
and evening hours ahead of a crossing cold front. VFR can be
expected away from storms, but more than one period of strong to
possibly severe storms is possible at any terminal. Storms could
bring impacts like wind gusts of 40 to 50 knots, large hail, and
torrential rainfall creating IFR to LIFR visibilities. Three
hour TEMPO groups were included in TAFs during the highest-risk
period for each terminal.
Storms will exit the region this evening with a cold front, with
a brief period of VFR expected. MVFR to IFR ceiling/visibility
should develop overnight with low level moisture in place due to
the recent and forecast rainfall. VFR conditions may then return
by mid-morning Sunday as high pressure returns.
.OUTLOOK...
VFR returns with high pressure on Sunday, before widespread
restrictions Monday and Tuesday with the approach and passage of
a cold front. VFR returns Wednesday under high pressure.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Flood Watch until 2 AM EDT Sunday for PAZ013-014-020-021-029-
073-074.
OH...Flood Watch until 2 AM EDT Sunday for OHZ039>041-049-050.
WV...Flood Watch until 2 AM EDT Sunday for WVZ001>003.
&&
SYNOPSIS...Craven
NEAR TERM...Craven
SHORT TERM...Craven/Hefferan
LONG TERM...Craven/Hefferan
AVIATION...CLHazardous Weather Outlook...UPDATED National Weather Service Pittsburgh PA 138 PM EDT Sat Aug 12 2023 OHZ039>041-049-050-PAZ013-014-020-021-029-073-074-WVZ001>003-131745- Tuscarawas-Carroll-Columbiana-Harrison-Jefferson OH-Lawrence-Butler- Beaver-Allegheny-Washington-Westmoreland- Higher Elevations of Westmoreland-Hancock-Brooke-Ohio- 138 PM EDT Sat Aug 12 2023 ...TORNADO WATCH 634 IN EFFECT UNTIL 9 PM EDT THIS EVENING... ...FLOOD WATCH IN EFFECT THROUGH LATE TONIGHT... This Hazardous Weather Outlook is for east central Ohio, southwest Pennsylvania, western Pennsylvania, and northern 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. Tornado Watch. Flood Watch. Significant severe weather is possible this afternoon and evening across the Ohio River Valley. Tornadoes, hail, and damaging wind gusts are possible along with locally heavy rain. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Confidence is increasing that severe weather and heavy rain is possible Monday afternoon/evening across the region. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures. OHZ048-057>059-068-069-PAZ007>009-015-016-022-077-078-WVZ004-131745- Coshocton-Muskingum-Guernsey-Belmont-Noble-Monroe-Mercer-Venango- Forest-Clarion-Jefferson PA-Armstrong-Indiana- Higher Elevations of Indiana-Marshall- 138 PM EDT Sat Aug 12 2023 ...TORNADO WATCH 634 IN EFFECT UNTIL 9 PM EDT THIS EVENING... This Hazardous Weather Outlook is for east central Ohio, northwest Pennsylvania, western Pennsylvania and the 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. Tornado Watch. Significant severe weather is possible this afternoon and evening across the Ohio River Valley. Tornadoes, hail, and damaging wind gusts are possible along with locally heavy rain. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Confidence is increasing that severe weather and heavy rain is possible Monday afternoon/evening across the region. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures. PAZ031-075-076-WVZ012-021-509>514-131745- Greene-Fayette-Higher Elevations of Fayette-Wetzel-Marion-Monongalia- Ridges of Eastern Monongalia and Northwestern Preston-Preston- Eastern Preston-Western Tucker-Eastern Tucker- 138 PM EDT Sat Aug 12 2023 This Hazardous Weather Outlook is for southwest Pennsylvania and northern West Virginia. .DAY ONE...This afternoon and tonight. Significant severe weather is possible this evening. Tornadoes, hail, and damaging wind gusts are possible along with locally heavy rain. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Confidence is increasing that severe weather and heavy rainfall is possible Monday afternoon/evening across the region. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures. Craven
Preliminary Local Storm Report
National Weather Service Pittsburgh PA
940 AM EDT Sat Aug 12 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0400 AM Rain 1 NE Sewickley Hills 40.57N 80.11W
08/12/2023 M3.36 inch Allegheny PA Public
&&
Event Number PBZ2302101
CLSpecial Weather Statement
National Weather Service Pittsburgh PA
312 PM EDT Sat Aug 12 2023
PAZ009-121945-
Forest PA-
312 PM EDT Sat Aug 12 2023
...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN FOREST COUNTY
THROUGH 345 PM EDT...
At 311 PM EDT, Doppler radar was tracking a strong thunderstorm near
Marienville, moving east at 15 mph.
HAZARD...Wind gusts up to 50 mph and penny size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Marienville.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
A Tornado Watch remains in effect until 900 PM EDT for northwestern
Pennsylvania.
&&
LAT...LON 4144 7896 4144 7898 4145 7898 4145 7906
4147 7919 4161 7919 4163 7900 4163 7896
TIME...MOT...LOC 1911Z 269DEG 14KT 4154 7915
MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH
RackleySpecial Weather Statement
National Weather Service Pittsburgh PA
334 PM EDT Sat Aug 12 2023
PAZ009-122000-
Forest PA-
334 PM EDT Sat Aug 12 2023
...A STRONG THUNDERSTORM WILL IMPACT FOREST COUNTY THROUGH 400 PM
EDT...
At 334 PM EDT, Doppler radar was tracking a strong thunderstorm near
Tionesta, or 14 miles west of Marienville, moving northeast at 40
mph.
HAZARD...Wind gusts up to 50 mph and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Tionesta, Kellettville, West Hickory, East Hickory, and Starr.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
A Tornado Watch remains in effect until 900 PM EDT for northwestern
and west central Pennsylvania.
&&
LAT...LON 4157 7896 4143 7928 4144 7940 4140 7940
4155 7951 4163 7951 4162 7895
TIME...MOT...LOC 1934Z 237DEG 36KT 4154 7938
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH
22The Pittsburgh radar (KPBZ), 115 km away, was scanning. The volume nearest the first event began at 19:39 UTC.
38 thunderstorm wind, 19 hail, 1 flash flood, 1 tornado, 1 flood. Local standard time, as filed.
Tree and wires down in Dempseytown, PA.
Mping report of quarter sized hail near Dempseytown, PA.
Quarter sized hail near Kaneville, PA.
Two trees down near Cherrytree, PA.
Quarter sized hail reported in Kaneville, PA.
Report of multiple trees down in southeast Jefferson County.
Trees and wires down along Portersville Road.
Trees and wires down near Jackson Center, PA.
Trees and wires down in the city of Sharon, PA.
A trained spotter reported that several roads in the town of New Castle were flooded.In addition, water, at least 8 inches deep, was flowing over highway 224 near Harbor Edinburg Rd.
Trees down near Bakerstown, PA.
Report of multiple trees down along Bakerstown Road.
Quarter sized hail reported in Springdale, PA. Photo provided via social media.
NWS Employee reported trees down.
Report of a a large uprooted tree in West Deer Township.
Half dollar sized hail reported near Merwin, PA.
Quarter sized hail reported via Mping near Atlasburg, PA.
Half dollar hail reported via social media.
Tree limbs down northwest of Hickory, PA.
Quarter sized hail reported near North Washington, PA.
Quarter sized hail reported via the public.
Quarter sized hail reported along Beaver Run Road.
Report of many trees down along Beaver Run Road.
Report of a tree on a home near Edmon, PA.
Several large trees down in North Washington area.
Nickel sized hail reported near Salina, PA.
Report of multiple trees down in the city of Salina, PA.
Tree down along State Route 403 in the city of Cramer, PA.
Trees reported down on Brush Run Road and Green Cove Road.
Half dollar hail reported near Vienna, PA.
Tennis ball hail reported north of Claysville, PA. Picture provided.
Two inch sized hail reported near Taylorstown, PA.
The National Weather Service in Pittsburgh conducted a storm|survey and concluded the damage was consistent with an EF-1 tornado. |Tornado damage began along Valley View Road in East Finley township. |An intermittent, and extremely narrow damage path continued along |Cracraft Road where an attached patio roof was taken off along with |part of the roof to the main residence. Additional snapped |or uprooted trees were observed further east along the |street at a neighboring residense. The most significant damage |occurred just past the midpoint of the tornado track, along the west |side of PA Route 221 where a cluster of approximately 30 pine trees |were all snapped near the base up to approximately 1/3rd of the way |up the trees, consistent with a high end EF1 rating. Additional |damage was noted along PA 18 to a township shed and outbuilding. |This was the end of the observed damage track, with beginning and |end concident with a well-defined gate-to-gate velocity couplet and |hook echo present from the Pittsburgh Doppler Radar. Length and |times of this tornado have been updated based on the additional |damage obtained since yesterday's initial survey. The very narrow |width to this tornado is further supported by video of the event |provided to the National Weather Service via social media.
Ham radio operator reported nickel hail north of the city of Washington, PA.
Multiple photos of 2 inch hail just east of Claysville, PA.
Three inch hail reported near Claysville, PA.
Mping report of half dollar hail just west of Green Hills, PA.
Golf ball hail reported by the public north of Green Hills, PA.
Basement flooding reported at the Rain Drop In II near Marion Center in Indiana county as noted on social media. There was also water flowing over the route 119.
NWS Employee reported large branches McDonald, PA.
Trees down along Laurel Run Road.
A NWS Employee reported trees down at mile marker 27 on I-79.
Barn destroyed along Brush Run Road and trees down along Lone Pine Road.
MPing report of tree limbs down in Mt. Pleasant, PA.
Trees down in the city of Wind Ridge, PA.
Report of multiple trees down near Bethlehem Center Elementary School.
Multiple trees snapped at the top.
Trees down in the city of Rices Landing, PA.
Multiple trees down in the city of Carmichaels, PA.
Power lines down along McClellandtown Road and Spring Road.
Large limbs down near Uledi, PA.
Trained spotter reported trees down on New Salem and Kaider Road.
Mping report of trees uprooted near Walnut Hill Road.
Trees down in the city of Greensboro, PA.
Spotter reported that a trailer collapsed and occupants were trapped north of Smithfield, PA. No known injuries.
Wires and trees down along Walnut Hill Road.
An emergency manager reported damage to festival tents along Main Street.
An emergency manager reported damage to festival tents along Main Street.
Trees down along Jeffrey Lane.
Trees down in the city of Dilliner, PA.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2023Every state in 2023This day in weather historyThe tornado archive for Pennsylvania, 2023Warnings in Pennsylvania, August 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: 1132005, 1131986, 1131987, 1132004, 1131988, 1132041, 1132007, 1132043, 1132044, 1135754, 1132008, 1132036, 1131989, 1132316, 1132037, 1131990, 1131991, 1131992, 1132006, 1131993, 1131994, 1131995, 1132040, 1132046, 1132009, 1131996, 1132047, 1132015, 1132024, 1131997, 1131998, 1131999, 1133999, 1132000, 1132001, 1132002, 1132003, 1132313, 1135787, 1132054, and more.