Alert archive / Pennsylvania / Flash Flood Warnings in 1989

Flash Flood Warning 33, NWS Philadelphia/Mount Holly

August 12, 1989Bucks County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 12, 1989, 5:11 PM EDT for Bucks County, Montgomery County, Pennsylvania. It was in force for 64 min.

The area

The counties it named.

The facts

Issued
Aug 12, 1989, 5:11 PM EDT (21:11 UTC)
Expired
Aug 12, 1989, 6:15 PM EDT
In force
64 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

Counties Bucks County, PA, Montgomery 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

Atlantic City In, NJ (KACY), launched 12:00Z, 9.2 hours before the alert went out and 111 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, Atlantic City In, NJ at 12:00Z on 1989-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 6 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, Atlantic City In, NJ at 12:00Z on 1989-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 60 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
6 J/kg
Mixed-layer CIN
-83 J/kg
Mixed-layer LCL
703 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
60 m²/s²
0-3 km storm-relative helicity
77 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPHL 122114
FFWPHL
PAC017-091-122215-
 
BULLETIN - EBS ACTIVATION REQUESTED
URBAN FLOOD WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA PA
511 PM EDT SAT AUG 12 1989
 
THE NATIONAL WEATHER SERVICE IN PHILADELPHIA HAS ISSUED AN
 
URBAN FLOOD WARNING EFFECTIVE UNTIL  615 PM EDT
FOR PEOPLE IN THE FOLLOWING COUNTIES...
 
IN SOUTHEAST PENNSYLVANIA
          ...BUCKS...CENTRAL MONTGOMERY
 
AT 5 PM WEATHER SERVICE RADAR SHOWED AN AREA OF MODERATE TO HEAVY
 
RAIN IN CENTRAL MONTGOMERY COUNTY PENNSYLVANIA.  A WEATHER SPOTTER
REPORTED THREE QUARTERS OF AN INCH OF RAIN IN NORRISTOWN IN A HALF
HOUR PERIOD.  THIS AREA OF HEAVY RAIN WAS MOVING NORTH AROUND 25 MPH
AND WILL MOVE INTO BUCKS COUNTY PENNSYLVANIA SHORTLY.
 
THESE HEAVY RAINS WILL CAUSE FLOODING OF ROADWAYS AND POOR DRAINAGE
AREAS.
 
 
 
 
IF YOU ARE IN THE WARNED COUNTY IN AN AREA SUBJECT TO FLOODING
MOVE TO HIGHER GROUND.  DO NOT DRIVE THROUGH FLOOD WATERS.
CLIMBING ATOP YOUR STALLED VELHICLE WILL NOT PREVENT YOU FROM
BEING SWEPT INTO DANGEROUS STREAM CONDITIONS AS WATER LEVELS RISE.

Nearby

Flash Flood Warnings in Pennsylvania, 1989Every flash flood warning in 1989

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.