Alert archive / Pennsylvania / Flash Flood Warnings in 1990

Flash Flood Warning 22, NWS Pittsburgh, PA

June 30, 1990Somerset County, Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at Jun 30, 1990, 8:27 PM EDT for Somerset County, Pennsylvania. It was in force for 33 min.

The area

The counties it named.

The facts

Issued
Jun 30, 1990, 8:27 PM EDT (00:27 UTC)
Expired
Jun 30, 1990, 9:00 PM EDT
In force
33 min
Issued by
NWS Pittsburgh, PA
Area
Whole counties

County Somerset 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 00:00Z, 0.5 hours before the alert went out and 103 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 1990-07-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1515 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 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 00:00Z on 1990-07-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -3 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
1515 J/kg
Mixed-layer CIN
-35 J/kg
Mixed-layer LCL
1023 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
-3 m²/s²
0-3 km storm-relative helicity
58 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.3

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPIT 010032
FFWPIT
PAC003-111-010100-
 
BULLETIN - EBS ACTIVATION REQUESTED
SEVERE THUNDERSTORM AND FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PITTSBURGH PA
827 PM EDT SAT JUN 30 1990
 
THE NATIONAL WEATHER SERVICE IN PITTSBURGH HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  900 PM EDT
AND A FLASH FLOOD WARNING EFFECTIVE UNTIL  900 PM EDT
FOR PEOPLE IN THE FOLLOWING COUNTIES...
 
IN WEST PENNSYLVANIA
          ...ALLEGHENY...SOMERSET
 
RADAR SHOWED A SEVERE THUNDERSTORM OVER SOUTHERN ALLEGHENY...BESIDES
CAUSING DAMAGING WIND AND LARGE HAIL...THIS STORM CAN ALSO CAUSE
FLOODING...ESPECIALLY OVER AREAS THAT HAVE GOTTEN PREVIOUS HEAVY
RAINS.
 
THE SEVERE STORM OVER FAYETTE COUNTY WILL BE MOVING ACROSS SOMERSET
COUNTY. THIS STORM HAS CAUSED DAMAGE WITH POWER LINES DOWNED TOO.
 
THERE ARE NOW SEVERE THUNDERSTORM AND FLASH FLOOD WARNINGS ON TIL 9 PM
FOR 10 COUNTIES...THESE ARE ARMSTRONG BUTLER CLARION CLEARFIELD
FAYETTE JEFFERSON WASHINGTON WESTMORELAND...AND NOW ALLEGHENY...
PITTSBURGH SOUTH HILLS AND SOMERSET.
 
SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55
MPH...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN.
FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON ZTHE LOWEST FLOOR
OF YOUR HOME OR BUSINESS.  HEAVY RAINS FLOOD ROADS QUICKLY SO
DON'T DRIVE INTO AREAS WHERE WATER COVERS THE ROAD.

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Special weather statement, Jun 30, 4:42 PM EDT, 3 hours 45 minutes before
PAZ001>006-013>015-WVZ001-302200-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE PITTSBURGH PA
445 PM EDT SAT JUN 30 1990

...SEVERE THUNDERSTORM WATCH FOR THE NORTHERN WEST VIRGINIA PANHANDLE
   AND MOST OF WESTERN PENNSYLVANIA TIL 10 PM...

JUST BEFORE 4 PM...RADAR SHOWED A THUNDERSTORM WITH STRONG WIND...
DANGEROUS LIGHTNING AND HEAVY DOWNPOURS MOVING INTO LAWRENCE BEAVER
SOUTHERN BUTLER AND WESTERN ALLEGHENY COUNTIES.  MOVEMENT WAS TO THE
SOUTHEAST AT 40 MILES AN HOUR.  THERE WERE OTHER STRONG STORMS OVER
WESTMORELAND COUNTY MOVING INTO THE JOHNSTOWN AREA AND ANOTHER OVER
BLAIR COUNTY MOVING INTO NORTHERN BEDFORD AND HUNTINGDON COUNTIES.

IF A STRONG STORM APPROACHES...TAKE COVER INDOORS AND AWAY FROM GLASS.
REMEMBER ALSO HEAVY DOWNPOURS CAN CAUSE FLOODING.
A WATCH OR WARNING IS ISSUED.

THERE IS SOME LIGHT AT THE END OF THE TUNNEL IN THE FORM OF A COLD
FRONT MOVING IN FROM THE UPPER MIDWEST. IT IS EXPECTEHD TO CROSS WESTERN
PENNSYLVANIA LATER TONIGHT FINALLY BRINGING A BREAK IN THE HEAT AND
HUMIDITY FOR SUNDAY.

RWH
Local storm report, Jun 30, 7:51 PM EDT, 36 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH, PA
749 PM EDT SAT JUN 30 1990

PRELIMINARY STORM REPORT WSFO PIT 6/30/90

TIME             EVENT            LOCATION
1648             G60KTS           BVI               (BEAVER CNTY ARPT)
1710        POWER LINES DOWN      BADEN             (BEAVER CNTY)
1738             11/2A            ALIQUIPPA         (BEAVER CNTY)
1740             11/4A            ALIQUIPPA         (BEAVER CNTY)
1740             13/4A            WSFO PIT          (ALLEGHENY CNTY)
1750        POWER LINES DOWN      MONACA            (BEAVER CNTY)
1755             11/2A            CORAOPOLIS        (ALLEGHENY CNTY)
1800              3/4A            8 MILES NW BUTLER (BUTLER CNTY)
1809              1A              CARNEGIE          (ALLEGHENY CNTY)
1844              1A              IMPERIAL          (ALLEGHENY CNTY)
1917              3/4A            PERRYOPOLIS       (FAYETTE)
1930              1A              OAKMONT           (ALLEGHENY)

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 30, 8:27 PM EDTFlash Flood WarningPBZAllegheny33 min
Jun 30, 8:59 PM EDTFlash Flood WarningPBZClearfield, Indiana, Jefferson61 min
Jun 30, 8:59 PM EDTFlash Flood WarningPBZCambria, Somerset, Westmoreland61 min
Jun 30, 8:59 PM EDTFlash Flood WarningPBZFayette61 min
Jun 30, 9:36 PM EDTSevere Thunderstorm WarningPBZClarion69 min
Jun 30, 9:54 PM EDTFlash Flood WarningPBZClearfield, Jefferson66 min
Jun 30, 9:54 PM EDTFlash Flood WarningPBZFayette66 min
Jun 30, 10:45 PM EDTSevere Thunderstorm WarningPBZClearfield, Indiana60 min
Jun 30, 10:57 PM EDTFlash Flood WarningPBZFayette2 hr
Jun 30, 11:59 PM EDTFlash Flood WarningPBZFayette4 hr
Jul 1, 11:27 AM EDTSevere Thunderstorm WarningPBZFayette63 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.