Alert archive / Pennsylvania / Flash Flood Warnings in 1999

Flash Flood Warning 39, NWS Pittsburgh, PA

April 9, 1999Fayette County, Greene County, Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at Apr 9, 1999, 2:58 PM EDT for Fayette County, Greene County, Pennsylvania. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Apr 9, 1999, 2:58 PM EDT (18:58 UTC)
Expired
Apr 9, 1999, 6:00 PM EDT
In force
3 hr
Issued by
NWS Pittsburgh, PA
Area
Whole counties

Counties Fayette County, PA, Greene County, PA

The radar

The Pittsburgh radar (KPBZ), 76 km from the middle of the area, began a volume at 19:01 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 7.0 hours before the alert went out and 241 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, Washington/Dulle, VA at 12:00Z on 1999-04-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Washington/Dulle, VA at 12:00Z on 1999-04-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 307 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2194 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
307 m²/s²
0-3 km storm-relative helicity
614 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 091858
FFWPIT
PAC051-059-092200-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PITTSBURGH PA
258 PM EDT FRI APR 9 1999

THE NATIONAL WEATHER SERVICE IN PITTSBURGH HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  FAYETTE COUNTY IN SOUTHWESTERN PENNSYLVANIA.
  GREENE COUNTY IN SOUTHWESTERN PENNSYLVANIA.

* UNTIL 600 PM EDT.

* AT 256 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED AN
  AREA OF VERY HEAVY RAIN JUST ENTERING THE WARNING AREA FROM THE
  SOUTHWEST...MOVING EAST NORTHEAST AT 40 MPH.

* THUNDERSTORMS WITH HEAVY RAIN ARE MOVING INTO THE WARNING AREA
  DURING THE NEXT HOUR. HEAVY RAINS THIS MORNING ALREADY SATURATED
  THE SOIL. FLOODING CAN BEGIN AFTER JU ST HALF AN INCH OF RAIN IN
  AN HOUR.

<<CALL TO ACTION>>MOVE TO HIGHER GROUND IF FLOOD WATERS THREATEN.

.END/

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, Apr 9, 11:55 AM EDT, 3 hours 3 minutes before
MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023-
029>032-WVZ001>004-012-021>023-041-092000-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
1155 AM EDT FRI APR 9 1999

...SEVERE THUNDERSTORMS POSSIBLE THIS AFTERNOON AND EVENING...

THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS ACROSS EAST CENTRAL
OHIO...NORTHERN WEST VIRGINIA...SOUTHWESTERN PENNSYLVANIA...AND
GARRETT COUNTY MARYLAND.

AN UPPER LEVEL DISTURBANCE AND ASSOCIATED SURFACE LOW WILL BE
APPROACHING THE REGION FROM THE WEST THIS AFTERNOON.  THE ATMOSPHERE
WILL REMAIN QUITE UNSTABLE AHEAD OF THIS DISTURBANCE AND THUNDERSTORMS
ARE EXPECTED TO REDEVELOP ACROSS THE REGION THIS AFTERNOON.  IT APPEARS
THAT DAMAGING STRAIGHT-LINE WINDS AND LARGE HAIL WILL BE THE MAIN SEVERE
WEATHER THREAT THIS AFTERNOON. THE THUNDERSTORMS WILL MOVE INTO EAST
CENTRAL OHIO AS EARLY AS 100 TO 200 PM AND INTO WESTERN PENNSYLVANIA AND
NORTHERN WEST VIRGINIA BY 300 TO 400 PM.

IN ADDITION...HEAVY DOWNPOURS ASSOCIATED WITH THESE STORMS MAY PRODUCE
LOCALIZED FLOODING PROBLEMS...ESPECIALLY WHERE SEVERAL STORMS PASS OVER
THE SAME LOCATION.  ISOLATED RAINFALL AMOUNTS OF OVER ONE INCH ARE
POSSIBLE.

AS A RESULT...SKYWARN AND HAM RADIO NETWORK ACTIVATION MAY BE NEEDED
THIS AFTERNOON.

STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA SOURCES
FOR FURTHER UPDATES ON THIS SEVERE WEATHER POTENTIAL.

WJD/RWH
Special weather statement, Apr 9, 11:55 AM EDT, 3 hours 3 minutes before
MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023-
029>032-WVZ001>004-012-021>023-041-092000-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
1155 AM EDT FRI APR 9 1999

...SEVERE THUNDERSTORMS POSSIBLE THIS AFTERNOON AND EVENING...

THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS ACROSS EAST CENTRAL
OHIO...NORTHERN WEST VIRGINIA...SOUTHWESTERN PENNSYLVANIA...AND
GARRETT COUNTY MARYLAND.

AN UPPER LEVEL DISTURBANCE AND ASSOCIATED SURFACE LOW WILL BE
APPROACHING THE REGION FROM THE WEST THIS AFTERNOON.  THE ATMOSPHERE
WILL REMAIN QUITE UNSTABLE AHEAD OF THIS DISTURBANCE AND THUNDERSTORMS
ARE EXPECTED TO REDEVELOP ACROSS THE REGION THIS AFTERNOON.  IT APPEARS
THAT DAMAGING STRAIGHT-LINE WINDS AND LARGE HAIL WILL BE THE MAIN SEVERE
WEATHER THREAT THIS AFTERNOON. THE THUNDERSTORMS WILL MOVE INTO EAST
CENTRAL OHIO AS EARLY AS 100 TO 200 PM AND INTO WESTERN PENNSYLVANIA AND
NORTHERN WEST VIRGINIA BY 300 TO 400 PM.

IN ADDITION...HEAVY DOWNPOURS ASSOCIATED WITH THESE STORMS MAY PRODUCE
LOCALIZED FLOODING PROBLEMS...ESPECIALLY WHERE SEVERAL STORMS PASS OVER
THE SAME LOCATION.  ISOLATED RAINFALL AMOUNTS OF OVER ONE INCH ARE
POSSIBLE.

AS A RESULT...SKYWARN AND HAM RADIO NETWORK ACTIVATION MAY BE NEEDED
THIS AFTERNOON.

STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA SOURCES
FOR FURTHER UPDATES ON THIS SEVERE WEATHER POTENTIAL.

WJD/RWH

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 9, 2:33 PM EDTSevere Thunderstorm WarningPBZWashington58 min
Apr 9, 2:44 PM EDTSevere Thunderstorm WarningPBZGreene59 min
Apr 9, 2:52 PM EDTFlash Flood WarningPBZAllegheny, Washington3 hr
Apr 9, 2:54 PM EDTSevere Thunderstorm WarningPBZAllegheny60 min
Apr 9, 3:11 PM EDTSevere Thunderstorm WarningPBZFayette, Westmoreland79 min
Apr 9, 3:39 PM EDTTornado WarningPBZWestmoreland51 min
Apr 9, 4:06 PM EDTFlash Flood WarningPBZBeaver2 hr
Apr 9, 4:19 PM EDTFlash Flood WarningPBZWestmoreland3 hr
Apr 9, 4:23 PM EDTFlash Flood WarningPBZButler3 hr
Apr 9, 5:51 PM EDTFlash Flood WarningPBZWashington, Westmoreland4 hr
Apr 9, 6:59 PM EDTFlash Flood WarningPBZFayette3 hr

Nearby

Flash Flood Warnings in Pennsylvania, 1999Every flash flood warning in 1999

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.