Alert archive / Pennsylvania / Flash Flood Warnings in 1989

Flash Flood Warning 5, NWS Philadelphia/Mount Holly

May 16, 1989Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at May 16, 1989, 1:06 PM EDT for Chester County, Pennsylvania. It was in force for 2 hr.

The area

The counties it named.

The facts

Issued
May 16, 1989, 1:06 PM EDT (17:06 UTC)
Expired
May 16, 1989, 3:15 PM EDT
In force
2 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

County Chester 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, 5.1 hours before the alert went out and 122 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 1989-05-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 15 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 1989-05-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 87 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
15 J/kg
Mixed-layer CIN
-187 J/kg
Mixed-layer LCL
540 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
87 m²/s²
0-3 km storm-relative helicity
121 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPHL 161710
FFWPHL
PAC029-161915-
BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA PA
106 PM EDT TUE MAY 16 1989

THE NATIONAL WEATHER SERVICE HAS ISSUED A FLASH FLOOD WARNING
EFFECTIVE UNTIL 315 PM EDT FOR PEOPLE IN THE FOLLOWING COUNTY

   IN THE SOUTHEAST PART OF PENNSYLVANIA
      CHESTER

FLOODING WAS INDICATED BY AN AUTOMATIC RIVER GAGE ON THE EAST BRANCH OF
THE BRANDYWINE CREEK NEAR DOWNINGTOWN. THE GAGE WAS NEARING THE FLOOD STAGE
OF 7 FEET.

A FLASH FLOOD WARNING MEANS FLOODING IS IMMINENT

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 VEHICLE WILL NOT PREVENT YOU FROM BEING SWEPT
INTO DANGEROUS STREAM CONDITIONS AS WATER LEVELS RISE.

A FLOOD WATCH REMAINS IN EFFECT FOR ALL OF SOUTHEAST PENNSYLVANIA
AND WESTERN SOUTHERN NEW JERSEY.

 ZEV

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.