Alert archive / Pennsylvania / Flash Flood Warnings in 1990

Flash Flood Warning 35, NWS Pittsburgh, PA

July 9, 1990Clarion County, Jefferson County, Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at Jul 9, 1990, 12:54 PM EDT for Clarion County, Jefferson County, Pennsylvania. It was in force for 2 hr.

The area

The counties it named.

The facts

Issued
Jul 9, 1990, 12:54 PM EDT (16:54 UTC)
Expired
Jul 9, 1990, 3:00 PM EDT
In force
2 hr
Issued by
NWS Pittsburgh, PA
Area
Whole counties

Counties Clarion County, PA, Jefferson 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, 4.9 hours before the alert went out and 112 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 1990-07-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1312 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 1990-07-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 143 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
1312 J/kg
Mixed-layer CIN
-49 J/kg
Mixed-layer LCL
1037 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
143 m²/s²
0-3 km storm-relative helicity
130 m²/s²
Significant tornado parameter
0.6
Supercell composite
5.3

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPIT 091655
FFWPIT
PAC031-065-091900-
 
BULLETIN - EBS ACTIVATION REQUESTED
SEVERE THUNDERSTORM AND FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PITTSBURGH PA
1254 PM EDT MON JUL 9 1990
 
THE NATIONAL WEATHER SERVICE IN PITTSBURGH HAS ISSUED A
SEVERE THUNDERSTORM AND FLASH FLOOD WARNING
EFFECTIVE UNTIL  300 PM EDT
FOR THE FOLLOWING LOCATIONS...
 
IN WEST PENNSYLVANIA
 
   ...CLARION COUNTY...JEFFERSON COUNTY
 
AT 1254 PM WEATHER RADAR SHOWED SEVERE THUNDERSTORMS NEAR COOK FOREST
STATE PARK TO JUST NORTH OF BROOKVILLE.
 
THESE STORMS WILL PRODUCE VERY HEAVY RAINS THAT WILL PRODUCE FLOODING.
 
NEVER DRIVE YOUR CAR INTO A FLOODED AREA.
 
WHEN THUNDERSTORMS ARE OCCURRING...PEOPLE SHOULD MOVE INSIDE A
STRONG BUILDING.  DO NOT STAND BY WINDOWS.  DON'T USE TELEPHONES
OR ELECTRICAL APPLIANCES UNLESS IN AN EMERGENCY UNTIL THE STORM
HAS PASSED.  MOTORISTS SHOULD NOT DRIVE INTO LOW WATER CROSSINGS.
 
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.

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 9, 12:54 PM EDTSevere Thunderstorm WarningPBZClarion, Jefferson2 hr
Jul 9, 1:12 PM EDTFlash Flood WarningPBZClearfield108 min
Jul 9, 1:12 PM EDTFlash Flood WarningPBZArmstrong108 min
Jul 9, 1:21 PM EDTSevere Thunderstorm WarningPBZClearfield99 min
Jul 9, 1:21 PM EDTSevere Thunderstorm WarningPBZArmstrong99 min
Jul 9, 1:35 PM EDTSevere Thunderstorm WarningPBZBeaver, Butler85 min
Jul 9, 2:09 PM EDTSevere Thunderstorm WarningPBZAllegheny81 min
Jul 9, 3:00 PM EDTFlash Flood WarningPBZArmstrong, Butler2 hr
Jul 9, 3:01 PM EDTFlash Flood WarningPBZAllegheny, Beaver89 min
Jul 9, 3:01 PM EDTSevere Thunderstorm WarningPBZAllegheny, Beaver89 min
Jul 9, 3:50 PM EDTFlash Flood WarningPBZWashington, Westmoreland100 min
Jul 9, 3:50 PM EDTSevere Thunderstorm WarningPBZWashington, Westmoreland100 min
Jul 9, 4:36 PM EDTFlash Flood WarningPBZAllegheny, Armstrong, Beaver114 min
Jul 9, 4:57 PM EDTSevere Thunderstorm WarningPBZSomerset48 min
Jul 9, 6:29 PM EDTFlash Flood WarningPBZArmstrong3 hr

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.