Alert archive / Pennsylvania / Flash Flood Warnings in 2021

Flash Flood Warning 12, NWS Pittsburgh, PA

July 7, 20215 counties in Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at Jul 7, 2021, 3:26 PM EDT for 5 counties in Pennsylvania. It was in force for 2 hr. 9 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: Jul 7, 2021, 3:26 PM EDT (19:26 UTC)
Expired: Jul 7, 2021, 5:30 PM EDT
In force: 2 hr
Issued by: NWS Pittsburgh, PA
Area: Storm-based polygon
Flood severity: None

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

The radar

The Pittsburgh radar (KPBZ), 32 km from the middle of the area, began a volume at 19:29 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
Jul 7, 3:33 PM EDT	FLASH FLOOD	2 W Edgewood, PA	ROADS CLOSED DUE TO FLOODING. VEHICLES STRANDED.
Jul 7, 3:40 PM EDT	FLASH FLOOD	Linhart, PA	SEVERAL VEHICLES STUCK IN HIGH WATER IN THE AREA OF THOMPSON RUN ROAD AND RODI ROAD. TIME ESTIMATED BASED ON RADAR.
Jul 7, 4:00 PM EDT	FLASH FLOOD	1 Se Sygan, PA	PINEWOOD AND LAKEWOOD DRIVE CLOSED DUE TO FLOODING WITH OVER 2 FEET OF RUNNING WATER AT INTERSECTION.
Jul 7, 4:03 PM EDT	FLASH FLOOD	1 Ese Wilkins Township, PA	CORRECTION TO CHANGE FROM TSTM WND DMG TO FLASH FLOOD REPORT FROM 1 ESE WILKINS TOWNSHIP. SEVERAL VEHICLES STUCK IN HIGH WATER IN THE AREA OF THOMPSON RUN RD AND RODI ROAD IN WILKINS TOWNSHIP.
Jul 7, 4:05 PM EDT	FLASH FLOOD	1 W Swissvale, PA	ROADWAY COMPLETELY COVERED WITH AT LEAST 3 FEET OF WATER AT COMMERCIAL BLVD IN NEAR SWISSHELM PARK.
Jul 7, 4:05 PM EDT	FLASH FLOOD	Crafton, PA	REPORT OF VEHICLE STUCK IN RISING WATER ON STATION STREET. TIME ESTIMATED BASED ON RADAR.
Jul 7, 4:15 PM EDT	FLASH FLOOD	Bridgeville, PA	UODATED REPORT SHOWED BALDWIN STREET WAS FLOODED AND CAUSED 4 HOMES TO BE EVACUATED ON BALDWIN STREET AND MCLAUGHLIN RUN ROAD.
Jul 7, 4:30 PM EDT	FLASH FLOOD	Bridgeville, PA	CREEK OUT OF BANK NEAR MCLAUGHLIN RUN AND BOWER HILL ROAD INTERSECTION.
Jul 7, 4:52 PM EDT	FLASH FLOOD	Bridgeville, PA	EVACUATIONS UNDERWAY DUE TO FLOODING ALONG BALDWIN STREET IN BRIDGEVILLE.

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, 7.4 hours before the alert went out and 16 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 505 J/kg
Mixed-layer CIN: -47 J/kg
Mixed-layer LCL: 1230 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 36 m²/s²
0-3 km storm-relative helicity: 53 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

147 
WGUS51 KPBZ 071926
FFWPBZ
PAC003-005-051-125-129-072130-
/O.NEW.KPBZ.FF.W.0012.210707T1926Z-210707T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Pittsburgh PA
326 PM EDT Wed Jul 7 2021

The National Weather Service in Pittsburgh has issued a

* Flash Flood Warning for...
  Allegheny County in southwestern Pennsylvania...
  Northwestern Fayette County in southwestern Pennsylvania...
  Central Washington County in southwestern Pennsylvania...
  Northwestern Westmoreland County in southwestern Pennsylvania...
  Southwestern Armstrong County in west central Pennsylvania...

* Until 530 PM EDT.

* At 326 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 1.5 inches of 
  rain have fallen. 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, McMurray, McKeesport, 
  Washington, Franklin Park, Canonsburg, Vandergrift, Apollo, 
  Gastonville, Shaler Township, Plum, West Mifflin, North Side 
  Pittsburgh and Baldwin.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4037 8021 4050 8014 4067 7995 4066 7961
      4055 7944 4043 7961 4031 7975 4014 7981
      4013 7986 4007 8010 4013 8036

FLASH FLOOD...RADAR INDICATED

$$

JL

2 follow-up statements

528 
WGUS71 KPBZ 072033
FFSPBZ

Flash Flood Statement
National Weather Service Pittsburgh PA
433 PM EDT Wed Jul 7 2021

PAC003-005-051-125-129-072130-
/O.CON.KPBZ.FF.W.0012.000000T0000Z-210707T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Allegheny PA-Armstrong PA-Fayette PA-Washington PA-Westmoreland
PA-
433 PM EDT Wed Jul 7 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 PM EDT THIS 
AFTERNOON FOR ALLEGHENY, NORTHWESTERN FAYETTE, CENTRAL WASHINGTON, 
NORTHWESTERN WESTMORELAND AND SOUTHWESTERN ARMSTRONG COUNTIES...

At 433 PM EDT, Radar indicates the heaviest rainfall has now moved 
out of the warned area, though flooding has been reported and is 
occuring per Emergency Management. Between 1.5 and 2.0 inches of 
rain have fallen.

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, McMurray, McKeesport, 
  Washington, Franklin Park, Canonsburg, Vandergrift, Apollo, 
  Gastonville, Shaler Township, Plum, West Mifflin, North Side 
  Pittsburgh and Baldwin.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4037 8021 4050 8014 4067 7995 4066 7961
      4055 7944 4043 7961 4031 7975 4014 7981
      4013 7986 4007 8010 4013 8036

FLASH FLOOD...OBSERVED

$$

449 
WGUS71 KPBZ 072127
FFSPBZ

Flash Flood Statement
National Weather Service Pittsburgh PA
527 PM EDT Wed Jul 7 2021

PAC003-005-051-125-129-072137-
/O.EXP.KPBZ.FF.W.0012.000000T0000Z-210707T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Allegheny PA-Armstrong PA-Fayette PA-Washington PA-Westmoreland
PA-
527 PM EDT Wed Jul 7 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 530 PM EDT THIS AFTERNOON FOR 
ALLEGHENY, NORTHWESTERN FAYETTE, CENTRAL WASHINGTON, NORTHWESTERN 
WESTMORELAND AND SOUTHWESTERN ARMSTRONG COUNTIES...

The heavy rain has ended, but locations within the warning have been 
replaced by a Flood Advisory across portions of Allegheny and 
Washington county as residual runoff continues to support ongoing, 
urban flooding. Please continue to heed remaining road closures.

LAT...LON 4037 8021 4050 8014 4067 7995 4066 7961
      4055 7944 4043 7961 4031 7975 4014 7981
      4013 7986 4007 8010 4013 8036

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 7, 1:36 PM EDT	Special Weather Statement	PBZ	Fayette	24 min
Jul 7, 1:57 PM EDT	Special Weather Statement	PBZ	Fayette	18 min
Jul 7, 2:01 PM EDT	Special Weather Statement	PBZ	Greene	14 min
Jul 7, 2:10 PM EDT	Special Weather Statement	PBZ	Westmoreland	20 min
Jul 7, 2:25 PM EDT	Severe Thunderstorm Warning	PBZ	Greene, Washington	20 min
Jul 7, 2:32 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Beaver, Washington	13 min
Jul 7, 2:42 PM EDT	Severe Thunderstorm Warning	PBZ	Beaver	18 min
Jul 7, 2:54 PM EDT	Severe Thunderstorm Warning	PBZ	Beaver, Washington	36 min
Jul 7, 2:58 PM EDT	Special Weather Statement	PBZ	Allegheny	32 min
Jul 7, 2:59 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny	31 min
Jul 7, 3:01 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Washington	29 min
Jul 7, 3:13 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Beaver, Washington	32 min
Jul 7, 3:19 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Washington, Westmoreland	26 min
Jul 7, 3:36 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Washington	24 min
Jul 7, 3:45 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Armstrong, Butler, Westmoreland	30 min
Jul 7, 3:47 PM EDT	Special Weather Statement	PBZ	Beaver	28 min
Jul 7, 3:53 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny	37 min
Jul 7, 4:01 PM EDT	Severe Thunderstorm Warning	PBZ	Butler	29 min
Jul 7, 4:21 PM EDT	Severe Thunderstorm Warning	PBZ	Beaver, Lawrence	39 min
Jul 7, 4:28 PM EDT	Severe Thunderstorm Warning	PBZ	Armstrong, Butler, Clarion	32 min
Jul 7, 4:33 PM EDT	Severe Thunderstorm Warning	PBZ	Armstrong, Indiana, Jefferson	27 min
Jul 7, 4:35 PM EDT	Severe Thunderstorm Warning	PBZ	Armstrong, Butler, Clarion, Venango	25 min
Jul 7, 4:40 PM EDT	Severe Thunderstorm Warning	PBZ	Indiana, Westmoreland	13 min
Jul 7, 4:58 PM EDT	Severe Thunderstorm Warning	PBZ	Butler, Lawrence, Mercer, Venango	47 min
Jul 7, 4:59 PM EDT	Severe Thunderstorm Warning	PBZ	Armstrong, Clarion, Jefferson	31 min
Jul 7, 5:01 PM EDT	Severe Thunderstorm Warning	PBZ	Armstrong, Indiana, Jefferson	29 min
Jul 7, 5:06 PM EDT	Severe Thunderstorm Warning	PBZ	Clarion, Forest, Jefferson	24 min
Jul 7, 5:20 PM EDT	Severe Thunderstorm Warning	PBZ	Mercer, Venango	25 min
Jul 7, 5:24 PM EDT	Areal Flood Advisory	PBZ	Allegheny, Washington, Westmoreland	111 min
Jul 7, 5:24 PM EDT	Severe Thunderstorm Warning	PBZ	Clarion, Forest, Jefferson	51 min
Jul 7, 6:40 PM EDT	Severe Thunderstorm Warning	PBZ	Fayette, Greene	20 min
Jul 7, 7:19 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Washington	26 min
Jul 7, 7:22 PM EDT	Severe Thunderstorm Warning	PBZ	Fayette, Greene, Washington	23 min
Jul 7, 7:33 PM EDT	Severe Thunderstorm Warning	PBZ	Fayette, Greene, Washington	27 min
Jul 7, 7:37 PM EDT	Severe Thunderstorm Warning	PBZ	Greene	23 min

Nearby

Flash Flood Warnings in Pennsylvania, 2021 Every 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.