Alert archive / Pennsylvania / Flash Flood Warnings in 1990

Flash Flood Warning 33, NWS Pittsburgh, PA

July 5, 1990Fayette County, Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at Jul 5, 1990, 2:34 PM EDT for Fayette County, Pennsylvania. It was in force for 2 hr.

The area

The counties it named.

The facts

Issued
Jul 5, 1990, 2:34 PM EDT (18:34 UTC)
Expired
Jul 5, 1990, 5:00 PM EDT
In force
2 hr
Issued by
NWS Pittsburgh, PA
Area
Whole counties

County Fayette 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, 6.6 hours before the alert went out and 67 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 1990-07-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2521 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 1990-07-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 58 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
2521 J/kg
Mixed-layer CIN
-60 J/kg
Mixed-layer LCL
821 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
58 m²/s²
0-3 km storm-relative helicity
78 m²/s²
Significant tornado parameter
0.5
Supercell composite
3.3

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPIT 051846 COR
FFWPIT
PAC111-051-052100-

BULLETIN - EBS ACTIVATION REQUESTED
SEVERE THUNDERSTORM AND FLASH FLOOD WARNING...CORRECTED
NATIONAL WEATHER SERVICE PITTSBURGH PA
245 PM EDT THU JUL 5 1990

THE NATIONAL WEATHER SERVICE IN PITTSBURGH HAS ISSUED A
SEVERE THUNDERSTORM WARNING UNTIL 330 PM EDT FOR SOMERSET COUNTY.

A FLASH FLOOD WARNING IS
EFFECTIVE UNTIL  500 PM EDT FOR FAYETTE COUNTY.

AT 230 PM EDT NATIONAL WEATHER SERVICE INDICATED A SEVERE THUNDERSTORM
ENTERING WESTERN SOMERSET COUNTY HEADING TOWARD CONFLUENCE. IT MOVING
SOUTHEAST AT 25 MILES AN HOUR.

REPEATED STORMS MOVING NORTHWEST TO SOUTHEAST OVER FAYETTE COUNTY
CONTINUES TO PRODUCE HEAVY DOWNPOURS THAT HAVE BEEN OCCURRING OVER THE
LAST FEW HOURS.  REPEATED TRAIN EFFECT RAINS COULD BE CAUSING FLOODING
IN PORTIONS OF FAYETTE COUNTY.

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 THE 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, Jul 5, 10:48 AM EDT, 3 hours 46 minutes before
PAZ003-005-006-013>015-WVZ001-051900-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
1045 AM EDT THU JUL 5 1990

...THUNDERSTORMS WITH STRONG WIND GUSTS AND HEAVY DOWNPOURS ARE
   POSSIBLE LATE THIS MORNING AND THIS AFTERNOON ACROSS THE
   NORTHERN WEST VIRGINIA PANHANDLE AND SOUTHERN PENNSYLVANIA...

A LINE OF SHOWERS AND THUNDERSTORMS HAVE DEVELOPED THIS MORNING AND
EXTENDED FROM DUBOIS THROUGH SLIPPERY ROCK TO NEW CASTLE INTO OHIO. THE
LINE WAS ABOUT 20 MILES WIDE AND WAS MOVING SOUTHEAST AT 25 MILES AN
HOUR.   SOME STORMS MAY HAVE STRONG WIND GUSTS AND HAIL PLUS DANGEROUS
LIGHTNING AND HEAVY DOWNPOURS THAT MAY CAUSE FLOODING IN LOW-LYING
PLACES AND AREAS OF POOR DRAINAGE.

THE LINE WILL MOVE THROUGH THE GREATER PITTSBURGH AIRPORT AREA AROUND
1130 AM...THE CITY OF PITTSBURGH AROUND NOON...SOUTHERN ALLEGHENY
COUNTY AROUND 1230 PM...AND THE JOHNSTOWN AREA AROUND 130 PM.

KEEP AN EYE ON THE SKY FOR THREATENING THUNDERSTORMS...AND LISTEN FOR
FORECAST UPDATES AND POSSIBLE WATCHES AND WARNINGS.

ALSO KEEP THESE SAFETY TIPS IN MIND.  WHENEVER THUNDERSTORMS
THREATEN...ITS BEST TO TAKE SHELTER INSIDE A STRONG BUILDING AND AWAY
FROM GLASS.  IF YOU ARE CAUGHT OUTSIDE...BE AWARE THAT LIGHTNING IS AS
MUCH A HAZARD AS HIGH WIND.  AVOID ISOLATED TREES AND METAL OBJECTS.
GO TO LOW SPOTS...CROUCH DOWN AND COVER YOUR HEAD...BUT LOOKOUT FOR
FLOODING FROM HEAVY DOWNPOURS.  WHEN FLOODING THREATENS...SEEK HIGHER
GROUND...BUT DONT GO THROUGH ANY FLOOD WATERS TO GET THERE.  THATS TRUE
WHETHER YOU ARE DRIVING OR ON FOOT.

TODAYS STRONGER THAN USUAL THUNDERSTORMS WILL BE CAUSED BY A COLD FRONT
SLICING THROUGH THE HIGH HEAT AND HUMIDITY CURRENTLY OVER THE WESTERN
PENNSYLVANIA REGION.  THE GOOD NEWS FOR TONIGHT AND FRIDAY IS THE
COMFORTABLY COOLER AND DRIER AIR BEHIND THIS FRONT.

STEWART/PALKO/REHAK/WAGNER
Special weather statement, Jul 5, 12:01 PM EDT, 2 hours 33 minutes before
PAZ003-005-006-013>015-WVZ001-052200-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
1155 AM EDT THU JUL 5 1990

...FLASH FLOOD WATCH HAS BEEN EXTENDED TO 600 PM EDT AND A SEVERE
   THUNDERSTORM IS IN EFFECT UNTIL 600 PM EDT FOR THE NORTHERN WEST
   VIRGINIA PANHANDLE...AND IN WESTERN PENNSYLVANIA FOR THE
   SOUTHWESTERN...WESTERN INTERIOR...LAUREL MOUNTAINS...CENTRAL
   MOUNTAINS AND THE SOUTH CENTRAL AREAS...

THE FLASH FLOOD AND SEVERE THUNDERSTORM WATCH INCLUDES THE FOLLOWING
COUNTIES IN THE NORTHERN WEST VIRGINIA PANHANDLE...

HANCOCK...BROOKE...OHIO AND MARSHALL.

AND THE FOLLOWING COUNTIES IN WESTERN PENNSYLVANIA...

BUTLER...ARMSTRONG...INDIANA...BEAVER...ALLEGHENY...
WESTMORELAND...GREENE...
WASHINGTON...FAYETTE...CAMBRIA...SOMERSET...CLEARFIELD...
CENTRE...BLAIR...BEDFORD...FULTON...FRANKLIN...HUNTINGDON...MIFFLIN
AND JUNIATA...CLINTON.

THE WATCH AREA IS BASICALLY FROM THE COUNTIES SOUTH OF INTERSTATE 80
SOUTH TO THE SOUTHERN PENNSYLVANIA BORDER AS WELL AS THE NORTHERN WEST
VIRGINIA PANHANDLE.

AT 1145 AM EDT WEATHER SERVICE RADAR INDICATED A LINE OF SHOWERS AND
THUNDERSTORMS THAT EXTENDED FROM THE CITY OF CLEARFIELD IN CLEARFIELD
COUNTY TO NEAR EAST LIVERPOOL OHIO.  THE LINE WAS MOVING SOUTHEAST AT
25 MILES AN MOUR.  THE LINE WILL MOVE THROUGH THE DOWNTOWN PITTSBURGH
AROUND 1215 PM..SOUTHERN ALLEGHENY COUNTY AROUND 1245 PM...AND THE
JOHNSTOWN AREA AROUND 145 PM.  THESE STORMS MAY CONTAIN VERY HEAVY
RAINS THAT MAY CAUSE FLOODING...LARGE HAIL...GUSTY WINDS...AND
DANGEROUS LIGHTENING.

IF HEAVY RAINS PERSIST OVER THE SAME AREA FOR ANY LENGTH OF TIME...
FLASH FLOODING COULD OCCUR.HEAVY DOWNPOURS FROM THUNDERSTORMS CAN CAUSE
RAPID RISES IN STREAM AND CREEKS IN JUST A SHORT PERIOD OF TIME.  IF
YOU LIVE NEAR A STREAM OR CREEK KEEP ALERT.

ALSO KEEP THESE SAFETY TIPS IN MIND.  WHENEVER THUNDERSTORMS
THREATEN...ITS BEST TO TAKE SHELTER INSIDE A STRONG BUILDING AND AWAY
FROM GLASS.  IF YOU ARE CAUGHT OUTSIDE...BE AWARE THAT LIGHTNING IS AS
MUCH A HAZARD AS HIGH WIND.  AVOID ISOLATED TREES AND METAL OBJECTS.
GO TO LOW SPOTS...CROUCH DOWN AND COVER YOUR HEAD...BUT LOOKOUT FOR
FLOODING FROM HEAVY DOWNPOURS.  WHEN FLOODING THREATENS...SEEK HIGHER
GROUND...BUT DONT GO THROUGH ANY FLOOD WATERS TO GET THERE.  THATS TRUE
WHETHER YOU ARE DRIVING OR ON FOOT.

RAINFALL OF AROUND 2.00 INCHES OF RAIN IN 3 HOURS OR LESS COULD CAUSE
FLOODING.

IN ADDITION...HEAVY RAINS CAN CAUSE PONDING OF WATER ON ROADWAYS AND
POOR DRAINAGE AREAS.  REDUCE YOUR SPEED WHEN DRIVING THROUGH HEAVY
RAINS...AND NEVER DRIVE THROUGH A FLOODED AREA.

A FLOOD WATCH MEANS FLOODING IS A POSSIBILITY NOT A CERTAIN3TY.  KEEP
ALERT IF HEAVY RAINS PERSIST...AND BE PREPARED TO MOVE TO HIGHER GROUND
IF A WARNING IS ISSUED OR IF FLOODING IS OBSERVED.

PALKO/STEWART/REHAK/WAGNER

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 5, 11:59 AM EDTSevere Thunderstorm WarningPBZWashington61 min
Jul 5, 12:14 PM EDTSevere Thunderstorm WarningPBZCambria, Indiana61 min
Jul 5, 12:32 PM EDTSevere Thunderstorm WarningPBZFayette58 min
Jul 5, 12:59 PM EDTSevere Thunderstorm WarningPBZBlair, Cambria, Westmoreland61 min
Jul 5, 12:59 PM EDTSevere Thunderstorm WarningPBZWashington61 min
Jul 5, 1:32 PM EDTSevere Thunderstorm WarningPBZBedford, Somerset58 min
Jul 5, 1:32 PM EDTSevere Thunderstorm WarningPBZFayette58 min
Jul 5, 2:34 PM EDTSevere Thunderstorm WarningPBZSomerset56 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.