Alert archive / Pennsylvania / Flash Flood Warnings in 1999

Flash Flood Warning 49, NWS Pittsburgh, PA

May 18, 1999Allegheny County, Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at May 18, 1999, 9:55 PM EDT for Allegheny County, Pennsylvania. It was in force for 4 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
May 18, 1999, 9:55 PM EDT (01:55 UTC)
Expired
May 19, 1999, 2:00 AM EDT
In force
4 hr
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 01:56 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 00:00Z, 1.9 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 00:00Z on 1999-05-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 5 joules per kilogram.LCLEL10008507005003002001001 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 00:00Z on 1999-05-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -74 square meters per square second.1939Sfc1 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
5 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
514 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
-74 m²/s²
0-3 km storm-relative helicity
-36 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 190155
FFWPIT
PAC003-190600-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PITTSBURGH PA
955 PM EDT TUE MAY 18 1999

THE NATIONAL WEATHER SERVICE IN PITTSBURGH HAS EXTENDED THE

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

* UNTIL 200 AM EDT.

* NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUES TO INDICATE
  MODERATE TO HEAVY RAINFALL ACROSS EASTERN PORTIONS OF ALLEGHENY
  COUNTY MOVING NORTHEAST AT AROUND 10 MPH. RUNOFF FROM THIS
  RAINFALL CAN CAUSE FLOODING OF STREAMS AND CREEKS THROUGH 2 AM.

* LAW ENFORCEMENT AGENCIES HAVE REPORTED THAT FLOODING OF STREAMS
  AND LOW LYING AREAS CONTINUES IN AREAS SUCH AS TURTLE CREEK...
  WILMERDING...BRADDOCK...PITCAIRN AND MONROEVILLE.

<<CALL TO ACTION>>DON'T DRIVE INTO AREAS WHERE WATER COVERS THE
ROAD! BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS DIFFICULT TO
RECOGNIZE THE DANGERS OF FLOODING.

.END/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

Local storm report, May 18, 7:26 PM EDT, 2 hours 29 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH, PA
726 PM EDT TUE MAY 18 1999

TIME(EDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0430 PM    MARIANNA                  PA   WIND DAMAGE
05/18/99   WASHINGTON                     TREES DOWN

0605 PM    MORGANTOWN                WV   FLOODING
05/18/99   MONONGALIA                     FLOODING ACROSS PORTIONS
                                          OF INTERSTATE 79
Local storm report, May 18, 7:26 PM EDT, 2 hours 29 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH, PA
726 PM EDT TUE MAY 18 1999

TIME(EDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0430 PM    MARIANNA                  PA   WIND DAMAGE
05/18/99   WASHINGTON                     TREES DOWN

0605 PM    MORGANTOWN                WV   FLOODING
05/18/99   MONONGALIA                     FLOODING ACROSS PORTIONS
                                          OF INTERSTATE 79
Local storm report, May 18, 7:37 PM EDT, 2 hours 18 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH, PA
737 PM EDT TUE MAY 18 1999

TIME(EDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0430 PM    MARIANNA                  PA   WIND DAMAGE
05/18/99   WASHINGTON                     TREES DOWN

0605 PM    MORGANTOWN                WV   FLOODING
05/18/99   MONONGALIA                     FLOODING ACROSS INTERSTATE
                                          79

0625 PM    WAYNESBURG                PA   WIND DAMAGE
05/18/99   GREENE                         TREE DOWN

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.