Alert archive / Pennsylvania / Flash Flood Warnings in 1987

Flash Flood Warning 2, NWS Philadelphia/Mount Holly

July 2, 1987Bucks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 2, 1987, 11:02 PM EDT for Bucks County, Pennsylvania. It was in force for 4 hr.

The area

The counties it named.

The facts

Issued
Jul 2, 1987, 11:02 PM EDT (03:02 UTC)
Expired
Jul 3, 1987, 3:00 AM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

County Bucks 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 00:00Z, 3.0 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 00:00Z on 1987-07-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2072 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 00:00Z on 1987-07-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 112 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
2072 J/kg
Mixed-layer CIN
-30 J/kg
Mixed-layer LCL
691 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
112 m²/s²
0-3 km storm-relative helicity
175 m²/s²
Significant tornado parameter
1.2
Supercell composite
8.7

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPHL 030305
FFWPHL
PAC017-030700-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA PA
1102 PM EDT THU JUL 2 1987
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A FLASH FLOOD WARNING
EFFECTIVE UNTIL 300 AM EDT FOR THE FOLLOWING COUNTY OF
 
SOUTHEAST PENNSYLVANIA... BUCKS
                                                                         
AT 11 PM AUTOMATIC RIVER GAGES INDICATED THAT THE RIVER STAGE AT THE 
NESHAMINY CREEK AT LANGHORNE WAS APPROACHING ITS FLOOD STAGE. RAINFALL
AMOUNTS OF 3 TO 4 INCHES HAD OCCURRED EARLIER TODAY. THIS HEAVY RAINFALL 
ON TOP OF THE ALREADY SATURATED GROUND FROM YESTERDAYS RAIN...WILL
CAUSE THE NESHAMINY CREEK TO EXCEED BANKFULL.

 
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 FLOOD WATERS.
DO NOT WADE THROUGH FLOOD WATERS.
 
GRW

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.