Alert archive / Pennsylvania / Flash Flood Warnings in 2002

Flash Flood Warning 79, NWS Pittsburgh, PA

August 12, 2002Allegheny County, Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at Aug 12, 2002, 5:31 PM EDT for Allegheny County, Pennsylvania. It was in force for 119 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 12, 2002, 5:31 PM EDT (21:31 UTC)
Expired
Aug 12, 2002, 7:30 PM EDT
In force
119 min
Issued by
NWS Pittsburgh, PA
Area
Whole counties

County Allegheny County, PA

The radar

The Pittsburgh radar (KPBZ), 21 km from the middle of the area, began a volume at 21:32 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.

The nearest sounding before it

Pittsburgh, PA (KPIT), launched 12:00Z, 9.5 hours before the alert went out and 12 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 2002-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 387 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Pittsburgh, PA at 12:00Z on 2002-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 13 square meters per square second.1939Sfc1 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
387 J/kg
Mixed-layer CIN
-92 J/kg
Mixed-layer LCL
1043 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
13 m²/s²
0-3 km storm-relative helicity
40 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WGUS51 KPBZ 122131
FFWPBZ
PAC003-122330-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PITTSBURGH PA
527 PM EDT MON AUG 12 2002

THE NATIONAL WEATHER SERVICE IN PITTSBURGH HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  ALLEGHENY COUNTY IN PENNSYLVANIA

* UNTIL 730 PM EDT

* AT 527 PM EDT...NATIONAL WEATHER SERVICE RADAR INDICATED VERY      
  HEAVY RAIN WAS OVER EASTERN ALLEGHENY COUNTY. BETWEEN 1 AND 2      
  INCHES OF RAIN HAS OCCURRED. MORE HEAVY RAIN WILL CAUSE STREAMS    
  AND CREEKS TO OVERFLOW.

* OTHER LOCATIONS IN THE WARNING INCLUDE...ASPINWALL...BLAWNOX...    
  BRADDOCK HILLS...CHESWICK...MCKEESPORT...PITTSBURGH                
  ...LIBERTY...VERSAILLES...WEST HOMESTEAD... AND WHITAKER.

<<CALL TO ACTION>>DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE
WATER COVERS THE ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW
YOUR CAR TO CROSS SAFELY. VEHICLES CAUGHT IN RISING WATER SHOULD BE
ABANDONED QUICKLY. MOVE TO HIGHER GROUND.

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 2:52 PM EDTSevere Thunderstorm WarningPBZButler53 min
Aug 12, 4:13 PM EDTFlash Flood WarningPBZButler3 hr
Aug 12, 4:26 PM EDTSevere Thunderstorm WarningPBZWestmoreland64 min
Aug 12, 4:53 PM EDTFlash Flood WarningPBZBeaver3 hr
Aug 12, 5:04 PM EDTSevere Thunderstorm WarningPBZAllegheny56 min
Aug 12, 5:23 PM EDTFlash Flood WarningPBZWestmoreland3 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2002Every flash flood warning in 2002

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.