Alert archive / Pennsylvania / Flash Flood Warnings in 2002

Flash Flood Warning 62, NWS Pittsburgh, PA

July 18, 2002Allegheny County, Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at Jul 18, 2002, 5:39 PM EDT for Allegheny County, Pennsylvania. It was in force for 111 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 18, 2002, 5:39 PM EDT (21:39 UTC)
Expired: Jul 18, 2002, 7:30 PM EDT
In force: 111 min
Issued by: NWS Pittsburgh, PA
Area: Whole counties

County Allegheny County, PA

The radar

The Pittsburgh radar (KPBZ), 21 km from the middle of the area, began a volume at 21:42 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

Pittsburgh, PA (KPIT), launched 12:00Z, 9.7 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 177 J/kg
Mixed-layer CIN: -48 J/kg
Mixed-layer LCL: 1017 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 26 m²/s²
0-3 km storm-relative helicity: 45 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 
WGUS51 KPBZ 182139
FFWPBZ
PAC003-182330-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING...RETRANSMISSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
534 PM EDT THU JUL 18 2002

THE NATIONAL WEATHER SERVICE IN PITTSBURGH HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  ALLEGHENY COUNTY IN PENNSYLVANIA

* UNTIL 730 PM EDT

* AT 533 PM EDT...NATIONAL WEATHER SERVICE RADAR INDICATED NEARLY 2 
INCHES OF RAIN IN THE LAST HOUR IN CENTRAL AND SOUTH CENTRAL ALLEGHENY 
COUNTY...ESPECIALLY OVER SAW MILL RUN...FROM GREENTREE TO THE WEST END.
OTHER AREAS MAY ALSO BE AFFECTED...ESPECIALLY STEUBEN ROAD. 

<<CALL TO ACTION>>EXCESSIVE RUNOFF FROM THESE STORMS WILL CAUSE FLASH
FLOODING OF SMALL CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES.
ADDITIONALLY...COUNTRY ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS
AND STREAMS AND OTHER LOW LYING AREAS ARE SUBJECT TO FLASH FLOODING.

<<CALL TO ACTION>>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.

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.

NWS Pittsburgh, PA wrote its last area forecast discussion before this flash flood warning went out at Jul 18, 3:30 PM EDT, 2 hours 9 minutes earlier.

Area forecast discussion, Jul 18, 3:30 PM EDT, 2 hours 9 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
330 PM EDT THU JUL 18 2002

MOIST AIR MASS IN PLACE WILL BRING SHOWERS AND THUNDERSTORMS TO THE
AREA TONIGHT INTO TOMORROW DUE TO A WEAK SW TROUGH. ETA AND
AVN NOT AGREEING. ETA DRYING OUT TOO FAST WHILE AVN HOLDS MOISTURE IN
THROUGH SAT NIGHT AND SERN REGIONS THROUGH LATE SUN. APPROACHING COLD
FRONT IS DIGGING THROUGH THE CWA SLOWLY BRINGING SHWRS AND
THUNDERSTORMS W/ IT. SOUNDINGS SHOW PWS TO RANGING FROM 1.7 TO 2.0 FOR
NEXT FEW DAYS.

EXPECT HUMID CONDITIONS TO PERSIST THROUGH THIS WEEKEND AS FRONT AND
WAA LINGERS. VORT MAX DRIFTS SLOWLY EASTWARD ACROSS MISS VALLEY THROUGH
WEEKEND. LESS HUMID CONDITIONS WILL BE OFF AND ON THROUGHOUT NEXT
WEEK.

AVN BRINGS STRONG COLD FRONT INTO CWA BY NEXT THURSDAY.

.PBZ...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.

RLA

Nearby

Flash Flood Warnings in Pennsylvania, 2002 Every flash flood warning in 2002

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.