Alert archive / Pennsylvania / Flash Flood Warnings in 2021

Flash Flood Warning 44, NWS Pittsburgh, PA

September 1, 20217 counties in Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at Sep 1, 2021, 9:27 AM EDT for 7 counties in Pennsylvania. It was in force for 4 hr. 13 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
Sep 1, 2021, 9:27 AM EDT (13:27 UTC)
Expired
Sep 1, 2021, 1:24 PM EDT
In force
4 hr
Issued by
NWS Pittsburgh, PA
Area
Storm-based polygon
Flood severity
None

Counties Allegheny County, PA, Armstrong County, PA, Fayette County, PA, Greene County, PA, Indiana County, PA, Washington County, PA, Westmoreland County, PA

The radar

The Pittsburgh radar (KPBZ), 72 km from the middle of the area, began a volume at 13:30 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
Sep 1, 9:32 AM EDTFLASH FLOOD1 Nw Carbon, PANORTH GREENGATE ROAD - UNDERPASS FLOODED WITH FOUR FEET OF WATER. VEHICLE STUCK IN WATER, WITH ONE PERSON ESCAPING THROUGH THE VEHICLE WINDOW
Sep 1, 9:50 AM EDTFLASH FLOOD1 E Greensburg, PANEW ALEXANDRIA ROAD FLOODED
Sep 1, 9:50 AM EDTFLASH FLOOD1 S New Florence, PAFLOODING AT THE INTERSECTION OF SHANNON CREEK ROAD AND MICHIGAN LANE
Sep 1, 10:00 AM EDTHEAVY RAIN 2.46Greensburg, PA24-HOUR RAINFALL MEASUREMENT THROUGH 10AM
Sep 1, 10:13 AM EDTFLASH FLOOD1 Se Delmont, PAFLOODING IN A BARN WITH LIVESTOCK ON BUSINESS ROUTE 66
Sep 1, 10:15 AM EDTFLASH FLOOD1 Se New Florence, PAFLOODING ON FURNACE LANE
Sep 1, 10:40 AM EDTFLASH FLOOD1 Nnw Lloydsville, PALATROBE CRABTREE ROAD FLOODED
Sep 1, 10:40 AM EDTFLASH FLOODPenn, PASOUTH CARBON STREET FLOODED
Sep 1, 10:53 AM EDTFLASH FLOODMidway, PASTATE ROUTE 119 FLOODED NEAR SHADY LANE
Sep 1, 11:12 AM EDTFLASH FLOODCrabtree, PARIZZO ROAD FLOODED FROM CRABTREE CREEK
Sep 1, 11:19 AM EDTFLASH FLOODMidway, PAROUTE 119 IN THE AREA OF SOUTH GRANDE BOULEVARD IS CLOSED IN BOTH DIRECTIONS DUE TO FLOODING
Sep 1, 11:23 AM EDTHEAVY RAIN 3.04Monessen, PARAINFALL SINCE 2 AM.
Sep 1, 12:06 PM EDTFLASH FLOODMidway, PAROUTE 119 CLOSED DUE TO FLOODING; JACKS RUN CREEK OUT OF BANKS IN THIS LOCATION.

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, 1.5 hours before the alert went out and 55 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 2021-09-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2021-09-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -93 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
666 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
-93 m²/s²
0-3 km storm-relative helicity
-7 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

126 
WGUS51 KPBZ 011327
FFWPBZ
PAC003-005-051-059-063-125-129-011930-
/O.NEW.KPBZ.FF.W.0044.210901T1327Z-210901T1930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Pittsburgh PA
927 AM EDT Wed Sep 1 2021

The National Weather Service in Pittsburgh has issued a

* Flash Flood Warning for...
  Southeastern Allegheny County in southwestern Pennsylvania...
  Fayette County in southwestern Pennsylvania...
  Northeastern Greene County in southwestern Pennsylvania...
  Southeastern Washington County in southwestern Pennsylvania...
  Westmoreland County in southwestern Pennsylvania...
  South Central Armstrong County in west central Pennsylvania...
  Southwestern Indiana County in west central Pennsylvania...

* Until 330 PM EDT Wednesday.

* At 927 AM EDT, Doppler radar indicated heavy rain across the 
  warned area. Between 1 and 2 inches of rain have fallen. 
  Additional rainfall amounts of 1 to 2.5 inches are possible in the 
  warned area. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by heavy rain.

  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, Bethel Park, Monroeville, McMurray, Greensburg, 
  McKeesport, Uniontown, Jeannette, Canonsburg, Latrobe, 
  Connellsville, Gastonville, West Mifflin, Baldwin, Upper St. 
  Clair, Murrysville, South Park Township, Jefferson Hills, North 
  Versailles and Pleasant Hills.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 4032 8005 4043 7969 4055 7943 4040 7897
      4012 7918 4009 7926 4000 7933 3990 7940
      3985 7942 3983 7940 3990 7962 3978 7990
      4024 8021

FLASH FLOOD...RADAR INDICATED

$$

SH
3 follow-up statements
389 
WGUS71 KPBZ 011436
FFSPBZ

Flash Flood Statement
National Weather Service Pittsburgh PA
1036 AM EDT Wed Sep 1 2021

PAC003-005-051-059-063-125-129-011930-
/O.CON.KPBZ.FF.W.0044.000000T0000Z-210901T1930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Allegheny PA-Armstrong PA-Fayette PA-Greene PA-Indiana PA-
Washington PA-Westmoreland PA-
1036 AM EDT Wed Sep 1 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 330 PM EDT THIS 
AFTERNOON FOR SOUTHEASTERN ALLEGHENY, FAYETTE, NORTHEASTERN GREENE, 
SOUTHEASTERN WASHINGTON, WESTMORELAND, SOUTH CENTRAL ARMSTRONG AND 
SOUTHWESTERN INDIANA COUNTIES...

At 1036 AM EDT, local law enforcement reported heavy rain across the 
warned area. Between 1.5 and 2.5 inches of rain have fallen. 
Additional rainfall amounts of 1 to 2 inches are possible in the 
warned area. Flash flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Law enforcement 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, Bethel Park, Monroeville, McMurray, Greensburg, 
  McKeesport, Uniontown, Jeannette, Canonsburg, Latrobe, 
  Connellsville, Gastonville, West Mifflin, Baldwin, Upper St. 
  Clair, Murrysville, South Park Township, Jefferson Hills, North 
  Versailles and Pleasant Hills.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 4032 8005 4043 7969 4055 7943 4040 7897
      4012 7918 4009 7926 4000 7933 3990 7940
      3985 7942 3983 7940 3990 7962 3978 7990
      4024 8021

FLASH FLOOD...OBSERVED

$$

SH
843 
WGUS71 KPBZ 011600
FFSPBZ

Flash Flood Statement
National Weather Service Pittsburgh PA
1200 PM EDT Wed Sep 1 2021

PAC003-005-059-125-011610-
/O.CAN.KPBZ.FF.W.0044.000000T0000Z-210901T1930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Allegheny PA-Armstrong PA-Greene PA-Washington PA-
1200 PM EDT Wed Sep 1 2021

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHEASTERN ALLEGHENY, 
NORTHEASTERN GREENE, SOUTHEASTERN WASHINGTON AND SOUTH CENTRAL 
ARMSTRONG COUNTIES...

High water is receding. Please continue to heed remaining road 
closures.

A Flash Flood Watch remains in effect until 200 AM EDT Thursday for 
Portions of Pennsylvania. Portions of northern West Virginia.

LAT...LON 4014 7986 4023 7978 4023 7979 4039 7968
      4052 7944 4040 7897 4016 7915 4016 7916
      4012 7918 4012 7921 4009 7926 4000 7933
      3990 7940 3985 7942 3983 7940 3990 7962
      3978 7990 4003 7982

$$

PAC051-063-129-011930-
/O.CON.KPBZ.FF.W.0044.000000T0000Z-210901T1930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Fayette PA-Indiana PA-Westmoreland PA-
1200 PM EDT Wed Sep 1 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 330 PM EDT THIS 
AFTERNOON FOR CENTRAL FAYETTE, WESTMORELAND AND SOUTHWESTERN INDIANA 
COUNTIES...

At 1200 PM EDT, local law enforcement reported heavy rain across the 
warned area. Between 2.0 and 2.5 inches of rain have fallen. 
Additional rainfall amounts of 1 to 1.5 inches are possible in the 
warned area. Flash flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Law enforcement 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...
  Greensburg, Uniontown, Jeannette, Latrobe, Connellsville, 
  Murrysville, Mount Pleasant, Scottdale, Irwin, 
  McChesneytown-Loyalhanna, Blairsville, Manor, Youngwood, Derry, 
  Delmont, West Newton, Lawson Heights, New Stanton, South 
  Connellsville and Perryopolis.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 4014 7986 4023 7978 4023 7979 4039 7968
      4052 7944 4040 7897 4016 7915 4016 7916
      4012 7918 4012 7921 4009 7926 4000 7933
      3990 7940 3985 7942 3983 7940 3990 7962
      3978 7990 4003 7982

FLASH FLOOD...OBSERVED

$$

SH
857 
WGUS71 KPBZ 011724
FFSPBZ

Flash Flood Statement
National Weather Service Pittsburgh PA
124 PM EDT Wed Sep 1 2021

PAC051-063-129-011734-
/O.CAN.KPBZ.FF.W.0044.000000T0000Z-210901T1930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Fayette PA-Indiana PA-Westmoreland PA-
124 PM EDT Wed Sep 1 2021

...FLASH FLOOD WARNING FOR CENTRAL FAYETTE, WESTMORELAND AND 
SOUTHWESTERN INDIANA COUNTIES HAS BEEN REPLACED WITH A FLOOD 
WARNING...

The flash flood warning has been replaced with a base flood warning. 
Flooding is still occuring.

LAT...LON 4014 7986 4023 7978 4023 7979 4039 7968
      4052 7944 4040 7897 4016 7915 4016 7916
      4012 7918 4012 7921 4009 7926 4000 7933
      3990 7940 3985 7942 3983 7940 3990 7962
      3978 7990 4003 7982

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 1, 5:05 AM EDTAreal Flood AdvisoryPBZAllegheny, Beaver, Fayette, Washington, Westmoreland104 min
Sep 1, 6:23 AM EDTFlash Flood WarningPBZAllegheny, Armstrong, Beaver, Butler, Indiana, Washington and 1 more5 hr
Sep 1, 7:16 AM EDTFlash Flood WarningPBZArmstrong, Indiana, Westmoreland6 hr
Sep 1, 7:21 AM EDTFlash Flood WarningPBZFayette, Greene6 hr
Sep 1, 7:50 AM EDTFlash Flood WarningPBZWashington3 hr
Sep 1, 10:26 AM EDTAreal Flood AdvisoryPBZWashington109 min
Sep 1, 11:23 AM EDTAreal Flood AdvisoryPBZAllegheny, Armstrong, Beaver, Butler, Indiana, Washington and 1 more52 min
Sep 1, 11:30 AM EDTRiver Flood WarningPBZIndiana, Westmoreland16 hr
Sep 1, 11:30 AM EDTRiver Flood WarningPBZFayette39 hr
Sep 1, 11:30 AM EDTRiver Flood WarningPBZFayette, Washington, Westmoreland28 hr
Sep 1, 11:30 AM EDTRiver Flood WarningPBZAllegheny, Westmoreland40 hr
Sep 1, 11:30 AM EDTRiver Flood WarningPBZAllegheny, Washington, Westmoreland33 hr
Sep 1, 1:15 PM EDTAreal Flood WarningPBZFayette2 hr
Sep 1, 1:16 PM EDTAreal Flood WarningPBZIndiana, Westmoreland2 hr
Sep 1, 1:24 PM EDTAreal Flood WarningPBZFayette, Indiana, Westmoreland2 hr

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.