Alert archive / Pennsylvania / Flash Flood Warnings in 2021

Flash Flood Warning 27, NWS Pittsburgh, PA

August 13, 20214 counties in Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at Aug 13, 2021, 9:15 PM EDT for 4 counties in Pennsylvania. It was in force for 4 hr. 3 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 13, 2021, 9:15 PM EDT (01:15 UTC)
Expired
Aug 14, 2021, 1:33 AM EDT
In force
4 hr
Issued by
NWS Pittsburgh, PA
Area
Storm-based polygon
Flood severity
None

Counties Forest County, PA, Lawrence County, PA, Mercer County, PA, Venango County, PA

The radar

The Pittsburgh radar (KPBZ), 99 km from the middle of the area, began a volume at 01:15 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
Aug 13, 9:45 PM EDTFLASH FLOODCherrytree, PAFLOODING ACROSS SEVERAL ROADS IN THE AREA.
Aug 13, 9:45 PM EDTFLASH FLOODHadley, PAHIGHWAY 358 FLOODED BETWEEN SANDY LAKE AND GREENVILLE BY HADLEY RD
Aug 13, 11:40 PM EDTFLASH FLOODRouseville, PACHERRY RUN CREEK OUT OF ITS BANKS IN CORNPLANTER TOWNSHIP. BRIDGE WASHED OUT. ROUTE 8 ALSO CLOSED FROM ROUTE 417 TO THE INTERSECTION OF ROUTE 227.

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 00:00Z, 1.3 hours before the alert went out and 112 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 00:00Z on 2021-08-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1815 joules per kilogram.LCLEL10008507005003002001001 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 00:00Z on 2021-08-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 73 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
1815 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
1196 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
73 m²/s²
0-3 km storm-relative helicity
111 m²/s²
Significant tornado parameter
0.7
Supercell composite
5.8

Open this sounding in Storm Lab

The text

As transmitted.

361 
WGUS51 KPBZ 140115
FFWPBZ
PAC053-073-085-121-140415-
/O.NEW.KPBZ.FF.W.0027.210814T0115Z-210814T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Pittsburgh PA
915 PM EDT Fri Aug 13 2021

The National Weather Service in Pittsburgh has issued a

* Flash Flood Warning for...
  Western Forest County in northwestern Pennsylvania...
  Mercer County in northwestern Pennsylvania...
  Northern Venango County in northwestern Pennsylvania...
  Northwestern Lawrence County in western Pennsylvania...

* Until 1215 AM EDT.

* At 915 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...
  Hermitage, Sharon, Oil City, Franklin, Sharpsville, Greenville, 
  Sugarcreek, Farrell, New Wilmington, Mercer, Pulaski, Hasson 
  Heights, Stoneboro, Seneca, New Bedford, West Middlesex, Polk, 
  Sandy Lake, Clark and Wheatland.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

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 4143 8052 4148 8029 4149 8000 4159 7985
      4162 7974 4162 7953 4143 7952 4131 8004
      4115 8016 4101 8052

FLASH FLOOD...RADAR INDICATED

$$

Brown
4 follow-up statements
317 
WGUS71 KPBZ 140212
FFSPBZ

Flash Flood Statement
National Weather Service Pittsburgh PA
1012 PM EDT Fri Aug 13 2021

PAC053-073-085-121-140415-
/O.CON.KPBZ.FF.W.0027.000000T0000Z-210814T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Forest PA-Lawrence PA-Mercer PA-Venango PA-
1012 PM EDT Fri Aug 13 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1215 AM EDT SATURDAY 
FOR WESTERN FOREST, MERCER, NORTHERN VENANGO AND NORTHWESTERN 
LAWRENCE COUNTIES...

At 1012 PM EDT, Doppler radar indicated thunderstorms producing 
heavy rain across the warned area. Between 2 and 3 inches of rain 
have fallen. 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...
  Hermitage, Sharon, Oil City, Franklin, Sharpsville, Greenville, 
  Sugarcreek, Farrell, New Wilmington, Mercer, Pulaski, Hasson 
  Heights, Stoneboro, Seneca, New Bedford, West Middlesex, Polk, 
  Sandy Lake, Clark and Wheatland.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

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 4143 8052 4148 8029 4149 8000 4159 7985
      4162 7974 4162 7953 4143 7952 4131 8004
      4115 8016 4101 8052

FLASH FLOOD...RADAR INDICATED

$$
700 
WGUS71 KPBZ 140346
FFSPBZ

Flash Flood Statement
National Weather Service Pittsburgh PA
1146 PM EDT Fri Aug 13 2021

PAC073-085-140356-
/O.CAN.KPBZ.FF.W.0027.000000T0000Z-210814T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lawrence PA-Mercer PA-
1146 PM EDT Fri Aug 13 2021

...FLASH FLOOD WARNING IS CANCELLED FOR MERCER AND NORTHWESTERN 
LAWRENCE COUNTIES...

Flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

LAT...LON 4149 8000 4159 7985 4162 7975 4162 7953
      4143 7952 4132 8000

$$

PAC053-121-140415-
/O.CON.KPBZ.FF.W.0027.000000T0000Z-210814T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Forest PA-Venango PA-
1146 PM EDT Fri Aug 13 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1215 AM EDT SATURDAY 
FOR WESTERN FOREST AND NORTHERN VENANGO COUNTIES...

At 1146 PM EDT, Doppler radar and automated rain gauges indicated 
heavy rain produced by thunderstorms. Cherry Run Creek was reported 
out of its banks, with a bridge washed out in Cornplanter Township. 
Route 8 has also been closed due to flooding from State Route 417 to 
the intersection of Route 227. Between 2 and 3 inches of rain have 
fallen. Flash flooding is already occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar and automated gauges.

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...
  Oil City, Franklin, Sugarcreek, Hasson Heights, Seneca, Polk, 
  Rouseville, Cooperstown, Woodland Heights, Pleasantville, Utica 
  and Oil Creek State Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

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 4149 8000 4159 7985 4162 7975 4162 7953
      4143 7952 4132 8000

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$
468 
WGUS51 KPBZ 140406
FFWPBZ
PAC053-121-140615-
/O.EXT.KPBZ.FF.W.0027.000000T0000Z-210814T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Pittsburgh PA
1206 AM EDT Sat Aug 14 2021

The National Weather Service in Pittsburgh has extended the

* Flash Flood Warning for...
  Western Forest County in northwestern Pennsylvania...
  Northern Venango County in northwestern Pennsylvania...

* Until 215 AM EDT.

* At 1206 AM EDT, emergency management reported flooding. Cherry Run 
  Creek was reported out of its banks, with a bridge washed out in 
  Cornplanter Township. Route 8 has also been closed due to flooding 
  from State Route 417 to the intersection of Route 227. Between 2 
  and 3 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...
  Oil City, Franklin, Sugarcreek, Hasson Heights, Seneca, Polk, 
  Rouseville, Cooperstown, Woodland Heights, Pleasantville, Utica 
  and Oil Creek State Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 4149 8000 4159 7985 4162 7975 4162 7953
      4143 7952 4132 8000

FLASH FLOOD...OBSERVED

$$
812 
WGUS71 KPBZ 140533
FFSPBZ

Flash Flood Statement
National Weather Service Pittsburgh PA
133 AM EDT Sat Aug 14 2021

PAC053-121-140543-
/O.CAN.KPBZ.FF.W.0027.000000T0000Z-210814T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Forest PA-Venango PA-
133 AM EDT Sat Aug 14 2021

...FLASH FLOOD WARNING IS CANCELLED FOR WESTERN FOREST AND NORTHERN 
VENANGO COUNTIES...

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

LAT...LON 4149 8000 4159 7985 4162 7975 4162 7953
      4143 7952 4132 8000

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 13, 8:11 PM EDTSevere Thunderstorm WarningPBZArmstrong, Indiana, Westmoreland31 min
Aug 13, 8:32 PM EDTSpecial Weather StatementPBZIndiana28 min
Aug 13, 8:41 PM EDTSpecial Weather StatementPBZMercer34 min
Aug 13, 8:47 PM EDTSpecial Weather StatementPBZVenango28 min
Aug 13, 9:00 PM EDTSpecial Weather StatementPBZVenango30 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.