Alert archive / Pennsylvania / Flash Flood Warnings in 2021

Flash Flood Warning 6, NWS Pittsburgh, PA

June 13, 2021Allegheny County, Washington County, Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at Jun 13, 2021, 7:22 PM EDT for Allegheny County, Washington County, Pennsylvania. It was in force for 100 min. 5 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 13, 2021, 7:22 PM EDT (23:22 UTC)
Expired: Jun 13, 2021, 9:02 PM EDT
In force: 100 min
Issued by: NWS Pittsburgh, PA
Area: Storm-based polygon
Flood severity: None

Counties Allegheny County, PA, Washington County, PA

The radar

The Pittsburgh radar (KPBZ), 23 km from the middle of the area, began a volume at 23:25 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
Jun 13, 7:26 PM EDT	FLOOD	W Castle Shannon, PA	MINOR STREET FLOODING
Jun 13, 7:29 PM EDT	FLASH FLOOD	Muse, PA	STREAM OUT OF ITS BANKS FLOODING THE INTERSECTION OF GLADDEN RD AT TIMBER RUN RD.
Jun 13, 7:30 PM EDT	FLOOD	1 S Mcdonald, PA	MINOR STREET FLOODING
Jun 13, 7:45 PM EDT	FLASH FLOOD	1 N Hendersonville, PA	INTERSTATE 79 DOWN TO ONE LANE DUE TO FLASH FLOOD WATERS SUBMERGING ONE LANE. CORRECTED FOR PROPER EVENT TYPE.
Jun 13, 8:20 PM EDT	HEAVY RAIN 2.23	2 Nw Mcmurray, PA

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, 11.4 hours before the alert went out and 9 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: 1001 J/kg
Mixed-layer CIN: -33 J/kg
Mixed-layer LCL: 944 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 53 m²/s²
0-3 km storm-relative helicity: 47 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.3

Open this sounding in Storm Lab

The text

As transmitted.

575 
WGUS51 KPBZ 132322
FFWPBZ
PAC003-125-140115-
/O.NEW.KPBZ.FF.W.0006.210613T2322Z-210614T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Pittsburgh PA
722 PM EDT Sun Jun 13 2021

The National Weather Service in Pittsburgh has issued a

* Flash Flood Warning for...
  Southwestern Allegheny County in southwestern Pennsylvania...
  Central Washington County in southwestern Pennsylvania...

* Until 915 PM EDT.

* At 722 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 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, Mount Lebanon, Bethel Park, McMurray, Canonsburg, 
  Gastonville, Baldwin, Upper St. Clair, Scott Township, Whitehall, 
  South Park Township, Cecil-Bishop, Jefferson Hills, Brentwood, 
  Castle Shannon, Pleasant Hills, Bridgeville, McDonald, 
  Sturgeon-Noblestown and Oakdale.

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.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 4038 8024 4041 8018 4037 7998 4028 7996
      4016 8006 4035 8032

FLASH FLOOD...RADAR INDICATED

$$

2 follow-up statements

925 
WGUS71 KPBZ 132343
FFSPBZ

Flash Flood Statement
National Weather Service Pittsburgh PA
743 PM EDT Sun Jun 13 2021

PAC003-125-140115-
/O.CON.KPBZ.FF.W.0006.000000T0000Z-210614T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Allegheny PA-Washington PA-
743 PM EDT Sun Jun 13 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 915 PM EDT THIS 
EVENING FOR SOUTHWESTERN ALLEGHENY AND CENTRAL WASHINGTON COUNTIES...

At 743 PM EDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 1 and 2.5 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, Mount Lebanon, Bethel Park, McMurray, Canonsburg, 
  Gastonville, Baldwin, Upper St. Clair, Scott Township, Whitehall, 
  South Park Township, Cecil-Bishop, Jefferson Hills, Brentwood, 
  Castle Shannon, Pleasant Hills, Bridgeville, McDonald, 
  Sturgeon-Noblestown and Oakdale.

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.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 4038 8024 4041 8018 4037 7998 4028 7996
      4016 8006 4035 8032

FLASH FLOOD...RADAR INDICATED

$$

798 
WGUS71 KPBZ 140102
FFSPBZ

Flash Flood Statement
National Weather Service Pittsburgh PA
902 PM EDT Sun Jun 13 2021

PAC003-125-140112-
/O.CAN.KPBZ.FF.W.0006.000000T0000Z-210614T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Allegheny PA-Washington PA-
902 PM EDT Sun Jun 13 2021

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHWESTERN ALLEGHENY AND 
CENTRAL WASHINGTON COUNTIES...

Flood waters have receded. The heavy rain has ended. Flooding is no 
longer expected to pose a threat. Please continue to heed remaining 
road closures.

LAT...LON 4038 8024 4041 8018 4037 7998 4028 7996
      4016 8006 4035 8032

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 13, 8:24 AM EDT	Special Weather Statement	PBZ	Westmoreland	36 min
Jun 13, 8:36 AM EDT	Areal Flood Advisory	PBZ	Armstrong, Westmoreland	71 min
Jun 13, 8:51 AM EDT	Areal Flood Advisory	PBZ	Armstrong, Indiana	103 min
Jun 13, 9:02 AM EDT	Special Weather Statement	PBZ	Westmoreland	13 min
Jun 13, 9:39 AM EDT	Special Weather Statement	PBZ	Fayette	36 min
Jun 13, 10:42 AM EDT	Special Weather Statement	PBZ	Fayette	33 min
Jun 13, 1:37 PM EDT	Severe Thunderstorm Warning	PBZ	Greene	38 min
Jun 13, 1:57 PM EDT	Severe Thunderstorm Warning	PBZ	Greene	20 min
Jun 13, 2:08 PM EDT	Severe Thunderstorm Warning	PBZ	Greene	33 min
Jun 13, 3:55 PM EDT	Severe Thunderstorm Warning	PBZ	Butler, Lawrence, Mercer	35 min
Jun 13, 4:23 PM EDT	Severe Thunderstorm Warning	PBZ	Beaver, Butler, Lawrence	37 min
Jun 13, 5:29 PM EDT	Flash Flood Warning	PBZ	Allegheny, Westmoreland	3 hr
Jun 13, 5:33 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Beaver, Butler, Westmoreland	27 min
Jun 13, 5:43 PM EDT	Severe Thunderstorm Warning	PBZ	Indiana, Westmoreland	47 min
Jun 13, 5:53 PM EDT	Severe Thunderstorm Warning	PBZ	Clarion, Forest, Venango	17 min
Jun 13, 5:59 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Washington, Westmoreland	46 min
Jun 13, 6:12 PM EDT	Special Weather Statement	PBZ	Forest	33 min
Jun 13, 6:21 PM EDT	Severe Thunderstorm Warning	PBZ	Greene, Washington	39 min
Jun 13, 6:54 PM EDT	Areal Flood Advisory	PBZ	Allegheny, Washington, Westmoreland	2 hr
Jun 13, 6:58 PM EDT	Special Weather Statement	PBZ	Washington	47 min
Jun 13, 7:26 PM EDT	Special Weather Statement	PBZ	Fayette	34 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.