Alert archive / Pennsylvania / Flash Flood Warnings in 2021
Flash Flood Warning 23, NWS Pittsburgh, PA
NWS Pittsburgh, PA issued this flash flood warning at Aug 12, 2021, 7:31 PM EDT for Allegheny County, Washington County, Westmoreland County, Pennsylvania. It was in force for 3 hr. 7 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
- Aug 12, 2021, 7:31 PM EDT (23:31 UTC)
- Expired
- Aug 12, 2021, 10:30 PM EDT
- In force
- 3 hr
- Issued by
- NWS Pittsburgh, PA
- Area
- Storm-based polygon
- Flood severity
- None
Counties Allegheny County, PA, Washington County, PA, Westmoreland County, PA
The radar
The Pittsburgh radar (KPBZ), 31 km from the middle of the area, began a volume at 23:31 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
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 12, 7:40 PM EDT | FLASH FLOOD | New Kensington, PA | FLOODED ROADWAYS IN NEW KENSINGTON |
| Aug 12, 7:45 PM EDT | FLASH FLOOD | Arnold, PA | NORTH ST. AND CONSTITUTION BLVD FLOODED IN ARNOLD |
| Aug 12, 8:10 PM EDT | FLASH FLOOD | 1 W Lincoln-Lemington, PA | WASHINGTON BLVD BY HIGHLAND PARK CLOSED DUE TO FLOODING AND VEHICLE UNDERWATER IN VICINITY |
| Aug 12, 8:25 PM EDT | FLASH FLOOD | Duquesne Heights, PA | FLOODING ALONG SAW MILL RUN BY THE PARKWAY WEST RAMP |
| Aug 12, 9:40 PM EDT | FLASH FLOOD | Carnegie, PA | VEHICLE STUCK IN WATER ON WASHINTON ROAD NEAR THE DAIRY QUEEN. |
| Aug 12, 9:44 PM EDT | FLASH FLOOD | Irwin, PA | RESIDUAL FLOODING ON TURNER VALLEY ROAD. |
| Aug 12, 9:58 PM EDT | FLASH FLOOD | Oakdale, PA | THREE FEET OF WATER IN 5 HOMES NEAR NOBLESTOWN ROAD, CLINTON AVE, AND VINCENNES ROAD. TOWN WAS TEMPORARILY SHUT DOWN DUE TO 18 INCHES OF WATER IN TOWN. |
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, 11.5 hours before the alert went out and 17 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.
- Mixed-layer CAPE
- 1075 J/kg
- Mixed-layer CIN
- -107 J/kg
- Mixed-layer LCL
- 890 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 163 m²/s²
- 0-3 km storm-relative helicity
- 129 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.8
The text
As transmitted.
423
WGUS51 KPBZ 122331
FFWPBZ
PAC003-125-129-130230-
/O.NEW.KPBZ.FF.W.0023.210812T2331Z-210813T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Pittsburgh PA
731 PM EDT Thu Aug 12 2021
The National Weather Service in Pittsburgh has issued a
* Flash Flood Warning for...
Southeastern Allegheny County in southwestern Pennsylvania...
Central Washington County in southwestern Pennsylvania...
Northwestern Westmoreland County in southwestern Pennsylvania...
* Until 1030 PM EDT.
* At 731 PM EDT, Radar indicated thunderstorms producing heavy rain
across the warned area. Between 0.5 and 1 inch of rain has fallen,
with additional 1.0 to 2.0 inches 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,
Monroeville, McMurray, Greensburg, McKeesport, Jeannette,
Canonsburg, Gastonville, Shaler Township, Plum, West Mifflin,
North Side Pittsburgh, Baldwin, Upper St. Clair, Murrysville and
Scott Township.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 4033 8035 4065 7970 4064 7969 4037 7943
4017 7989 4014 7995
FLASH FLOOD...RADAR INDICATED
$$3 follow-up statements
004
WGUS71 KPBZ 130019
FFSPBZ
Flash Flood Statement
National Weather Service Pittsburgh PA
819 PM EDT Thu Aug 12 2021
PAC003-125-129-130230-
/O.CON.KPBZ.FF.W.0023.000000T0000Z-210813T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Allegheny PA-Washington PA-Westmoreland PA-
819 PM EDT Thu Aug 12 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1030 PM EDT THIS
EVENING FOR SOUTHEASTERN ALLEGHENY, CENTRAL WASHINGTON AND
NORTHWESTERN WESTMORELAND COUNTIES...
At 819 PM EDT, Radar indicated thunderstorms producing heavy rain
across the warned area. Between 1 and 2 inches of rain have fallen,
with an additional 1 to 1.50 inches expected. Flash flooding is
ongoing or expected to begin shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Flash flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other poor
drainage and low-lying areas.
Some locations that will experience flash flooding include...
Pittsburgh, Penn Hills, Mount Lebanon, Bethel Park, Ross Township,
Monroeville, McMurray, Greensburg, McKeesport, Jeannette,
Canonsburg, Gastonville, Shaler Township, Plum, West Mifflin,
North Side Pittsburgh, Baldwin, Upper St. Clair, Murrysville and
Scott Township.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
&&
LAT...LON 4033 8035 4065 7970 4064 7969 4037 7943
4017 7989 4014 7995
FLASH FLOOD...RADAR INDICATED
$$797
WGUS71 KPBZ 130032
FFSPBZ
Flash Flood Statement
National Weather Service Pittsburgh PA
832 PM EDT Thu Aug 12 2021
PAC003-125-129-130230-
/O.CON.KPBZ.FF.W.0023.000000T0000Z-210813T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Allegheny PA-Washington PA-Westmoreland PA-
832 PM EDT Thu Aug 12 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1030 PM EDT THIS
EVENING FOR SOUTHEASTERN ALLEGHENY, CENTRAL WASHINGTON AND
NORTHWESTERN WESTMORELAND COUNTIES...
At 832 PM EDT, Emergency management reported flooding across the
warned area. Between 1.5 and 2.5 inches of rain have fallen, with an
additional 1.0 to 2.0 inches additional rainfall expected.
HAZARD...Life threatening flash flooding. Thunderstorms producing
flash flooding.
SOURCE...Emergency management reported.
IMPACT...Life threatening flash flooding of creeks and streams,
urban areas, highways, streets and underpasses.
Some locations that will experience flash flooding include...
Pittsburgh, Penn Hills, Mount Lebanon, Bethel Park, Ross Township,
Monroeville, McMurray, Greensburg, McKeesport, Jeannette,
Canonsburg, Gastonville, Shaler Township, Plum, West Mifflin,
North Side Pittsburgh, Baldwin, Upper St. Clair, Murrysville and
Scott Township.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
&&
LAT...LON 4033 8035 4065 7970 4064 7969 4037 7943
4017 7989 4014 7995
FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
$$182
WGUS71 KPBZ 130233
FFSPBZ
Flash Flood Statement
National Weather Service Pittsburgh PA
1033 PM EDT Thu Aug 12 2021
PAC003-125-129-130243-
/O.EXP.KPBZ.FF.W.0023.000000T0000Z-210813T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Allegheny PA-Washington PA-Westmoreland PA-
1033 PM EDT Thu Aug 12 2021
...FLASH FLOOD WARNING HAS EXPIRED FOR SOUTHEASTERN ALLEGHENY,
CENTRAL WASHINGTON AND NORTHWESTERN WESTMORELAND COUNTIES...
Flooding is no longer expected to pose a threat. Please continue to
heed remaining road closures.
LAT...LON 4033 8035 4065 7970 4064 7969 4037 7943
4017 7989 4014 7995
$$
SHThe office that day
Everything else NWS Pittsburgh, PA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 12, 3:15 AM EDT | Heat Advisory | PBZ | Allegheny, Armstrong, Beaver, Butler, Fayette, Greene and 3 more | 16 hr |
| Aug 12, 11:19 AM EDT | Special Weather Statement | PBZ | Mercer | 41 min |
| Aug 12, 11:33 AM EDT | Severe Thunderstorm Warning | PBZ | Lawrence, Mercer, Venango | 27 min |
| Aug 12, 11:49 AM EDT | Special Weather Statement | PBZ | Lawrence | 26 min |
| Aug 12, 11:59 AM EDT | Severe Thunderstorm Warning | PBZ | Beaver, Butler, Lawrence | 31 min |
| Aug 12, 12:16 PM EDT | Special Weather Statement | PBZ | Beaver | 29 min |
| Aug 12, 12:21 PM EDT | Severe Thunderstorm Warning | PBZ | Allegheny, Armstrong, Beaver, Butler, Clarion, Lawrence and 1 more | 39 min |
| Aug 12, 12:34 PM EDT | Severe Thunderstorm Warning | PBZ | Allegheny, Beaver, Butler, Westmoreland | 41 min |
| Aug 12, 12:56 PM EDT | Severe Thunderstorm Warning | PBZ | Allegheny, Armstrong, Butler, Indiana, Westmoreland | 49 min |
| Aug 12, 1:05 PM EDT | Severe Thunderstorm Warning | PBZ | Armstrong, Clarion, Indiana, Jefferson | 25 min |
| Aug 12, 1:26 PM EDT | Severe Thunderstorm Warning | PBZ | Armstrong, Indiana, Jefferson | 49 min |
| Aug 12, 4:16 PM EDT | Special Weather Statement | PBZ | Clarion, Venango | 29 min |
| Aug 12, 4:46 PM EDT | Severe Thunderstorm Warning | PBZ | Clarion, Venango | 44 min |
| Aug 12, 4:52 PM EDT | Special Weather Statement | PBZ | Mercer | 23 min |
| Aug 12, 4:56 PM EDT | Severe Thunderstorm Warning | PBZ | Forest, Venango | 35 min |
| Aug 12, 5:03 PM EDT | Severe Thunderstorm Warning | PBZ | Butler, Lawrence, Mercer, Venango | 42 min |
| Aug 12, 5:20 PM EDT | Severe Thunderstorm Warning | PBZ | Clarion, Jefferson | 40 min |
| Aug 12, 5:43 PM EDT | Flash Flood Warning | PBZ | Butler, Lawrence, Mercer, Venango | 3 hr |
| Aug 12, 5:43 PM EDT | Severe Thunderstorm Warning | PBZ | Butler, Lawrence | 47 min |
| Aug 12, 5:53 PM EDT | Severe Thunderstorm Warning | PBZ | Allegheny, Butler | 52 min |
| Aug 12, 6:06 PM EDT | Severe Thunderstorm Warning | PBZ | Allegheny, Beaver, Washington | 24 min |
| Aug 12, 6:10 PM EDT | Severe Thunderstorm Warning | PBZ | Armstrong, Butler, Clarion, Forest, Jefferson, Venango | 50 min |
| Aug 12, 6:13 PM EDT | Flash Flood Warning | PBZ | Armstrong, Butler, Clarion, Forest, Jefferson, Venango | 3 hr |
| Aug 12, 6:33 PM EDT | Severe Thunderstorm Warning | PBZ | Allegheny, Washington | 42 min |
| Aug 12, 6:38 PM EDT | Severe Thunderstorm Warning | PBZ | Allegheny, Armstrong, Butler, Clarion, Indiana, Jefferson and 1 more | 67 min |
| Aug 12, 6:40 PM EDT | Severe Thunderstorm Warning | PBZ | Washington | 20 min |
| Aug 12, 6:53 PM EDT | Severe Thunderstorm Warning | PBZ | Clarion, Forest, Jefferson | 37 min |
| Aug 12, 7:09 PM EDT | Severe Thunderstorm Warning | PBZ | Allegheny, Armstrong, Fayette, Indiana, Washington, Westmoreland | 81 min |
| Aug 12, 7:43 PM EDT | Severe Thunderstorm Warning | PBZ | Indiana | 34 min |
| Aug 12, 7:53 PM EDT | Severe Thunderstorm Warning | PBZ | Allegheny, Washington | 37 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.