Alert archive / Pennsylvania / Flash Flood Warnings in 1987

Flash Flood Warning 4, NWS State College, PA

September 12, 1987Cumberland County, Pennsylvania

NWS State College, PA issued this flash flood warning at Sep 12, 1987, 8:20 PM EDT for Cumberland County, Pennsylvania. It was in force for 4 hr.

The area

The counties it named.

The facts

Issued
Sep 12, 1987, 8:20 PM EDT (00:20 UTC)
Expired
Sep 13, 1987, 12:20 AM EDT
In force
4 hr
Issued by
NWS State College, PA
Area
Whole counties

County Cumberland 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

Washington/Dulle, VA (KIAD), launched 00:00Z, 0.3 hours before the alert went out and 135 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 00:00Z on 1987-09-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 575 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, Washington/Dulle, VA at 00:00Z on 1987-09-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 95 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
575 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
518 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
95 m²/s²
0-3 km storm-relative helicity
105 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.8

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KHAR 130022
FFWHAR
PAC041-130420-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE HARRISBURG PA
820 PM EDT SAT SEP 12 1987
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A FLASH FLOOD WARNING
EFFECTIVE UNTIL 1220 AM EDT FOR THE FOLLOWING COUNTY OF
 
SOUTH CENTRAL PENNSYLVANIA... CUMBERLAND
                                                                         
THE NATIONAL WEATHER SERVICE HAS ISSUED A FLASH FLOOD WARNING FOR 
CUMBERLAND COUNTY. RAINFALL AMOUNTS OF 1.50 INCHES TO 3.50 INCHES 
HAVE BEEN REPORTED DURING THE PAST HOUR.THE CONODOGUINET CREEK 
IS NOW 5.90 FEET AND IS EXPECTED TO REACH BETWEEN 10 AND 11 FEET 
SUNDAY MORNING. 
 
A FLASH FLOOD WARNING MEANS FLOODING IN OCCURRING OR IS IMMINENT.
 
IF YOU GET ANY INDICATION THAT FLOOD WATERS ARE APPROACHING MOVE TO
HIGHER GROUND IMMEDIATELY.  DO NOT DRIVE THROUGH FLOOUD WATERS.
DO NOT WADE THROUGH FLOOD WATERS.
 
PN

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, Sep 12, 8:13 PM EDT, 7 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HARRISBURG PA.
815 PM EDT    SAT  SEP 12 1987

 ...HEAVY RAINS PRODUCE STREET AND BASEMENT FLOODING IN CUMBERLAND
    COUNTY...

RADAR SHOWED A HEAVY THUNDERSTORM THAT MOVED THROUGH CUMBERLAND COUNTY
DURING THE PAST HOUR.

WE HAVE RECEIVED NUMEROUS REPORTS OF STREET AND BASEMENT FLOODING AND
HIGHWAY FLOODING  IN MANY AREAS OF THE COUNTY BY THE COUNTY DISPATCHER.

RAINFALL AMOUNTS OF 1.50 INCHES TEO 2.50 INCHES HAVE BEEN REPORTED BY
MANY RAINFALL OBSERVERS.

THIS THUNDERSTORM WILL BE MOVING OUT OF CUMBERLAND COUNTY AND INTO DAUPHIN
COUNTY BY 830 PM EDT.

 REMEMBER...DO NOT DRIVE THROUGH FLOODED ROADWAYS.

WSO HAR NEFF

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 12, 8:44 PM EDTFlash Flood WarningCTPDauphin4 hr
Sep 12, 9:56 PM EDTFlash Flood WarningCTPCumberland6 hr

Nearby

Flash Flood Warnings in Pennsylvania, 1987Every flash flood warning in 1987

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.