Alert archive / Pennsylvania / Flash Flood Warnings in 1986

Flash Flood Warning 1, NWS Philadelphia/Mount Holly

December 25, 1986Bucks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Dec 25, 1986, 3:29 AM EST for Bucks County, Pennsylvania. It was in force for 61 min.

The area

The counties it named.

The facts

Issued
Dec 25, 1986, 3:29 AM EST (08:29 UTC)
Expired
Dec 25, 1986, 4:30 AM EST
In force
61 min
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, 8.5 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 1986-12-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 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 1986-12-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 425 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
514 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
425 m²/s²
0-3 km storm-relative helicity
493 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 KPHL 250830
FFWPHL
PAC017-250930-

BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA PA
329 AM EST THU DEC 25 1986

THE NATIONAL WEATHER SERVICE HAS ISSUED A FLASH FLOOD WARNING
EFFECTIVE UNTIL 430 AM EST FOR PEOPLE IN THE FOLLOWING COUNTY OF

SOUTHEAST PENNSYLVANIA...BUCKS

ONE TO TWO INCHES OF HEAVY RAINS FELL OVER EXTREME SOUTHEAST
PENNSYLVANIA OVERNIGHT AND THIS CAUSED THE NESHAMINY CREEK
TO RISE RAPIDLY. THE NESHAMINY CREEK WILL REACH FLOOD STAGE
OF 9 FEET BY 4 AM BUT THEN SUBSIDED RAPIDLY BELOW FLOOD BY 5AM.

A FLASH FLOOD WARNING MEANS FLOODING IS IMMINENT.

IF YOU GET ANY INDICATION THAT FLOOD WATERS ARE APPROACHING MOVE TO
3HIGHER GROUND IMMEDIATELY. DO NOT DRIVE THROUGH FLOOD WATERS.
DO NOT WADE THROUGH FLOOD WATERS.

RNS

Nearby

Flash Flood Warnings in Pennsylvania, 1986Every flash flood warning in 1986

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.