Alert archive / Pennsylvania / Flash Flood Warnings in 2021

Flash Flood Warning 10, NWS Pittsburgh, PA

June 30, 20214 counties in Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at Jun 30, 2021, 2:12 PM EDT for 4 counties in Pennsylvania. It was in force for 3 hr. 4 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jun 30, 2021, 2:12 PM EDT (18:12 UTC)
Expired
Jun 30, 2021, 5:15 PM EDT
In force
3 hr
Issued by
NWS Pittsburgh, PA
Area
Storm-based polygon
Flood severity
None

Counties Allegheny County, PA, Beaver County, PA, Washington County, PA, Westmoreland County, PA

The radar

The Pittsburgh radar (KPBZ), 27 km from the middle of the area, began a volume at 18:13 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

TimeReportWhereRemark
Jun 30, 2:14 PM EDTFLASH FLOODPleasant Hills, PAREPORT THAT US ROAD 51 THROUGH PLEASANT HILLS IS CLOSED DUE TO FLOODING.
Jun 30, 2:18 PM EDTFLASH FLOODWhitehall, PAREPORT OF ROADWAYS CLOSED DUE TO FLOODING IN WHITEHALL BOROUGH.
Jun 30, 2:28 PM EDTFLASH FLOOD1 E Dravosburg, PAREPORT OF WEST 5TH AVENUE FLOODING OUT IN MCKEESPORT.
Jun 30, 2:47 PM EDTFLASH FLOODWest Mifflin, PAEM REPORTING MULTIPLE REPORTS OF FLOODED ROADWAYS IN THE BALDWIN BORO, PLEASANT HILLS, WEST MIFFLING, AND WHITEHALL AREAS.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Pittsburgh, PA (KPIT), launched 12:00Z, 6.2 hours before the alert went out and 13 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Pittsburgh, PA at 12:00Z on 2021-06-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 807 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Pittsburgh, PA at 12:00Z on 2021-06-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 71 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
807 J/kg
Mixed-layer CIN
-49 J/kg
Mixed-layer LCL
1240 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
71 m²/s²
0-3 km storm-relative helicity
66 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.2

Open this sounding in Storm Lab

The text

As transmitted.

158 
WGUS51 KPBZ 301812
FFWPBZ
PAC003-007-125-129-302115-
/O.NEW.KPBZ.FF.W.0010.210630T1812Z-210630T2115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Pittsburgh PA
212 PM EDT Wed Jun 30 2021

The National Weather Service in Pittsburgh has issued a

* Flash Flood Warning for...
  Allegheny County in southwestern Pennsylvania...
  Central Washington County in southwestern Pennsylvania...
  Northwestern Westmoreland County in southwestern Pennsylvania...
  East Central Beaver County in western Pennsylvania...

* Until 515 PM EDT.

* At 212 PM EDT, Radar indicated thunderstorms producing heavy rain 
  across the warned area. Between 1 and 1.5 inches of rain have 
  fallen, with up to an 1.0 additional rainfall expected. Flash 
  flooding is ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Pittsburgh, Penn Hills, Mount Lebanon, Bethel Park, Ross Township, 
  McCandless Township, Monroeville, Moon Township, McMurray, 
  McKeesport, Franklin Park, Jeannette, Gastonville, Shaler 
  Township, Plum, West Mifflin, North Side Pittsburgh, Baldwin, 
  Upper St. Clair and Murrysville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 4062 8015 4062 7973 4044 7954 4025 7963
      4017 7984 4022 8001 4028 8015 4043 8034

FLASH FLOOD...RADAR INDICATED

$$
3 follow-up statements
941 
WGUS71 KPBZ 301852
FFSPBZ

Flash Flood Statement
National Weather Service Pittsburgh PA
252 PM EDT Wed Jun 30 2021

PAC003-007-125-129-302115-
/O.CON.KPBZ.FF.W.0010.000000T0000Z-210630T2115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Allegheny PA-Beaver PA-Washington PA-Westmoreland PA-
252 PM EDT Wed Jun 30 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 515 PM EDT THIS 
AFTERNOON FOR ALLEGHENY, CENTRAL WASHINGTON, NORTHWESTERN 
WESTMORELAND AND EAST CENTRAL BEAVER COUNTIES...

At 252 PM EDT, Radar indicated thunderstorms producing heavy rain 
across the warned area. Between 1.5 and 2 inches of rain have 
fallen, with an additional 1.0 to 1.50 inches expected. Flash 
flooding is already occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Pittsburgh, Penn Hills, Mount Lebanon, Bethel Park, Ross Township, 
  McCandless Township, Monroeville, Moon Township, McMurray, 
  McKeesport, Franklin Park, Jeannette, Gastonville, Shaler 
  Township, Plum, West Mifflin, North Side Pittsburgh, Baldwin, 
  Upper St. Clair and Murrysville.

Road closures have been reported by Emergency Management, especially 
along Route 51 in the South Hills.  Do not drive along flooded 
roadways.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 4062 8015 4062 7973 4044 7954 4025 7963
      4017 7984 4022 8001 4028 8015 4043 8034

FLASH FLOOD...RADAR INDICATED

$$
276 
WGUS71 KPBZ 301953
FFSPBZ

Flash Flood Statement
National Weather Service Pittsburgh PA
353 PM EDT Wed Jun 30 2021

PAC003-007-125-129-302115-
/O.CON.KPBZ.FF.W.0010.000000T0000Z-210630T2115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Allegheny PA-Beaver PA-Washington PA-Westmoreland PA-
353 PM EDT Wed Jun 30 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 515 PM EDT THIS 
AFTERNOON FOR ALLEGHENY, CENTRAL WASHINGTON, NORTHWESTERN 
WESTMORELAND AND EAST CENTRAL BEAVER COUNTIES...

At 353 PM EDT, Radar indicated the heaviest rainfall has now moved 
out, but widespread showers should continue to impact the area. 
Between 2.0 and 2.5 inches of rain have fallen, with an additional 
0.25 to 0.50 inches expected. Flash flooding is already occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Emergency management reported.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Pittsburgh, Penn Hills, Mount Lebanon, Bethel Park, Ross Township, 
  McCandless Township, Monroeville, Moon Township, McMurray, 
  McKeesport, Franklin Park, Jeannette, Gastonville, Shaler 
  Township, Plum, West Mifflin, North Side Pittsburgh, Baldwin, 
  Upper St. Clair and Murrysville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 4062 8015 4062 7973 4044 7954 4025 7963
      4017 7984 4022 8001 4028 8015 4043 8034

FLASH FLOOD...OBSERVED

$$
509 
WGUS71 KPBZ 302107
FFSPBZ

Flash Flood Statement
National Weather Service Pittsburgh PA
507 PM EDT Wed Jun 30 2021

PAC003-007-125-129-302117-
/O.EXP.KPBZ.FF.W.0010.000000T0000Z-210630T2115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Allegheny PA-Beaver PA-Washington PA-Westmoreland PA-
507 PM EDT Wed Jun 30 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 515 PM EDT THIS AFTERNOON FOR 
ALLEGHENY, CENTRAL WASHINGTON, NORTHWESTERN WESTMORELAND AND EAST 
CENTRAL BEAVER COUNTIES...

The heavy rain has ended and water is receding. However, residual 
runoff is still occuring, which may support localized flooding in 
prone locations.  Please continue to heed remaining road closures.

LAT...LON 4062 8015 4062 7973 4044 7954 4025 7963
      4017 7984 4022 8001 4028 8015 4043 8034

$$

The office that day

Everything else NWS Pittsburgh, PA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 29, 8:02 PM EDTAreal Flood AdvisoryPBZMercer, Venango118 min
Jun 30, 12:40 PM EDTSpecial Weather StatementPBZWashington50 min
Jun 30, 12:56 PM EDTSpecial Weather StatementPBZAllegheny34 min
Jun 30, 1:04 PM EDTSevere Thunderstorm WarningPBZWashington26 min
Jun 30, 1:06 PM EDTSevere Thunderstorm WarningPBZAllegheny, Washington, Westmoreland24 min
Jun 30, 1:19 PM EDTAreal Flood AdvisoryPBZAllegheny, Washington, Westmoreland3 hr
Jun 30, 1:23 PM EDTSevere Thunderstorm WarningPBZAllegheny, Washington, Westmoreland52 min
Jun 30, 1:29 PM EDTSpecial Weather StatementPBZWashington31 min
Jun 30, 1:52 PM EDTSpecial Weather StatementPBZIndiana23 min
Jun 30, 2:03 PM EDTSevere Thunderstorm WarningPBZIndiana, Westmoreland42 min
Jun 30, 2:14 PM EDTFlash Flood WarningPBZAllegheny, Washington2 hr
Jun 30, 2:26 PM EDTSevere Thunderstorm WarningPBZWashington49 min
Jun 30, 2:37 PM EDTSevere Thunderstorm WarningPBZIndiana38 min
Jun 30, 2:41 PM EDTSevere Thunderstorm WarningPBZAllegheny, Beaver, Washington34 min
Jun 30, 2:45 PM EDTSevere Thunderstorm WarningPBZIndiana, Westmoreland45 min
Jun 30, 3:03 PM EDTSpecial Weather StatementPBZArmstrong27 min
Jun 30, 3:13 PM EDTSpecial Weather StatementPBZGreene32 min
Jun 30, 3:29 PM EDTSpecial Weather StatementPBZFayette31 min
Jun 30, 3:32 PM EDTAreal Flood AdvisoryPBZArmstrong, Indiana3 hr
Jun 30, 3:35 PM EDTSpecial Weather StatementPBZForest25 min
Jun 30, 3:52 PM EDTSpecial Weather StatementPBZFayette23 min
Jun 30, 3:55 PM EDTSpecial Weather StatementPBZJefferson35 min
Jun 30, 4:29 PM EDTSpecial Weather StatementPBZButler31 min
Jun 30, 5:05 PM EDTSpecial Weather StatementPBZMercer25 min
Jun 30, 5:11 PM EDTSpecial Weather StatementPBZLawrence34 min
Jun 30, 5:58 PM EDTSevere Thunderstorm WarningPBZAllegheny, Beaver, Butler, Washington47 min
Jun 30, 6:44 PM EDTSpecial Weather StatementPBZAllegheny46 min

Nearby

Flash Flood Warnings in Pennsylvania, 2021Every flash flood warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.