Alert archive / Pennsylvania / Flash Flood Warnings in 1990

Flash Flood Warning 94, NWS Pittsburgh, PA

August 19, 1990Allegheny County, Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at Aug 19, 1990, 6:40 PM EDT for Allegheny County, Pennsylvania. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Aug 19, 1990, 6:40 PM EDT (22:40 UTC)
Expired
Aug 19, 1990, 9:26 PM EDT
In force
3 hr
Issued by
NWS Pittsburgh, PA
Area
Whole counties

County Allegheny County, PA

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

The nearest sounding before it

Pittsburgh, PA (KPIT), launched 12:00Z, 10.7 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 1990-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 103 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 1990-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 92 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
103 J/kg
Mixed-layer CIN
-50 J/kg
Mixed-layer LCL
687 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
92 m²/s²
0-3 km storm-relative helicity
158 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPIT 192239
FFWPIT
PAC003-200000-

BULLETIN  BROADCAST IMMEDIATELY
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PITTSBURGH PA
640 PM EDT SUN AUG 19 1990

THE NATIONAL WEATHER SERVICE IN PITTSBURGH HAS ISSUED A FLASH FLOOD
WARNING UNTIL 8PM  FOR THIS COUNTY IN

WESTERN PENNSYLVANIA...ALLEGHENY.

AT 630 PM NEARLY ONE AND A HALF INCHES OF RAIN IN JUST 45 MINUTES
WAS REPORTED ALONG THE OHIO RIVER IN ALLEGHENY COUNTY. BE OUT ON
LOOKOUT FOR POOR DRAINAGE FLOODING AND STREAMS GOING CLOSE TO OR
OVER THEIR BANKS.

A FLASH FLOOD WARNING MEANS FLOODING IS IMMINENT OR IN PROGRESS.
IF YOU GET ANY INDICATION THAT FLOOD WATERS ARE APPROACHING..MOVE TO
HIGHER GROUND IMMEDIATELY. DO NOT DRIVE THROUGH FLOODED AREAS.

A SEVERE THUNDERSTORM WARNING IS IN EFFECT UNTIL 7 PM FOR GREENE
COUNTY IN SOUTHWESTERN PENNSYLVANIA. HEAVY RAIN AND WIND DAMAGE WAS
REPORTED IN MARHSHALL COUNTY WEST VIRGINIA WITHIN THE HOUR. THE
SEVERE THUNDERSTORM WARNING CONTINUES IN OHIO AND MARSHALL COUNTIES
WEST VIRGINIA UNTIL 645 PM.

A FLASH FLOOD WATCH IS IN EFFECT UNTIL 5 AM MONDAY FOR THE NORTHERN
PANHANDLE OF WEST VIRGINIA AND FOR MOST OF WESTERN PENNSYLVANIA.

A SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 11 PM TONIGHT FOR
BROOKE OHIO AND MARSHALL COUNTIES IN THE NORTHERN PANHANDLE...AND
FOR ALLEGHENY GREENE FAYETTE WASHINGTON AND WESTMORELAND COUNTIES
IN SOUTHWESTERN PENNSYLVANIA.

IF MORE THAN 1.5 INCHES OF RAIN FALLS IN AN HOUR...FLOODING WILL
BEGIN.

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 19, 5:26 AM EDTFlash Flood WarningPBZGreene3 hr
Aug 19, 5:59 PM EDTSevere Thunderstorm WarningPBZGreene61 min
Aug 19, 6:54 PM EDTSevere Thunderstorm WarningPBZBeaver66 min
Aug 19, 6:54 PM EDTSevere Thunderstorm WarningPBZAllegheny3 hr
Aug 19, 7:40 PM EDTSevere Thunderstorm WarningPBZCambria80 min

Nearby

Flash Flood Warnings in Pennsylvania, 1990Every flash flood warning in 1990

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.