Alert archive / Pennsylvania / Flash Flood Warnings in 1990

Flash Flood Warning 84, NWS Pittsburgh, PA

July 21, 1990Allegheny County, Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at Jul 21, 1990, 2:05 PM EDT for Allegheny County, Pennsylvania. It was in force for 115 min.

The area

The counties it named.

The facts

Issued
Jul 21, 1990, 2:05 PM EDT (18:05 UTC)
Expired
Jul 21, 1990, 4:00 PM EDT
In force
115 min
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, 6.1 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 1990-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 41 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 1990-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 23 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
41 J/kg
Mixed-layer CIN
-57 J/kg
Mixed-layer LCL
573 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
23 m²/s²
0-3 km storm-relative helicity
38 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 
TTAA00 KPIT 211806
FFWPIT
PAC003-212000-
 
BULLETIN - EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PITTSBURGH PA
205 PM EDT SAT JUL 21 1990
 
THE NATIONAL WEATHER SERVICE IN PITTSBURGH HAS ISSUED A
FLASH FLOOD WARNING EFFECTIVE UNTIL 400 PM EDT
FOR THE FOLLOWING LOCATIONS...
 
IN WESTERN PENNSYLVANIA
 
   ...ALLEGHENY COUNTY
 
AT 200 PM WEATHER RADAR SHOWED HEAVY RAIN MOVING EASTWARD INTO
ALLEGHENY COUNTY. THIS AREA OF HEAVY RAIN EXTENDED WEST INTO
EASTERN OHIO...SO HEAVY DOWNPOURS WILL CONTINUE
OVER ALLEGHENY COUNTY FOR THE NEXT HOUR OR TWO.
 
 
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
Jul 21, 3:20 PM EDTFlash Flood WarningPBZWashington3 hr
Jul 21, 3:20 PM EDTFlash Flood WarningPBZAllegheny, Westmoreland3 hr

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.