Alert archive / Pennsylvania / Flash Flood Warnings in 1993

Flash Flood Warning 1, NWS Philadelphia/Mount Holly

March 4, 1993Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Mar 4, 1993, 4:52 PM EST for Chester County, Pennsylvania. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued
Mar 4, 1993, 4:52 PM EST (21:52 UTC)
Expired
Mar 5, 1993, 1:00 AM EST
In force
8 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

County Chester County, PA

The nearest sounding before it

Atlantic City In, NJ (KACY), launched 12:00Z, 9.9 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 1993-03-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 1993-03-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 243 square meters per square second.1939587897Sfc1 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
533 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
243 m²/s²
0-3 km storm-relative helicity
395 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 042212 COR
FFWPHL
PAC029-050600-

BULLETIN - EBS ACTIVATION REQUESTED
FLOOD WARNING...CORRECTION TO CHANGE TO SMALL STREAM FLOOD WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA PA
452 PM EST THU MAR 4 1993

THE NATIONAL WEATHER SERVICE IN PHILADELPHIA HAS ISSUED A
SMALL STREAM FLOOD WARNING EFFECTIVE UNTIL  100 AM EST
FOR PEOPLE IN THE FOLLOWING LOCATION...

IN SOUTHEAST PENNSYLVANIA

   ...CHESTER COUNTY

...FLOOD WARNING FOR BRANDYWINE CREEK AND ITS TRIBUTARIES...

     AT 430 PM A WEATHER SPOTTER REPORTED RED CLAY CREEK...A
TRIBUTARY OF THE BRANDYWINE...JUST OVER ITS BANKS.  AT DOWNINGTOWN
ON THE BRANDYWINE CREEK THE RIVER GAGE WAS AT 6 FT AND RISING.  FLOOD
STAGE IS 7 FT.  AT CHADDS FORD THE RIVER GAGE READ 5.85 FT.
FLOOD STAGE IS 9 FT.

     WHILE THE HEAVIEST PRECIPITATION HAS NOW MOVED NORTH OF
CHESTER COUNTY...1 TO 2 INCHES OF RAIN FELL EARLIER IN THE DAY.
THE RUNOFF FROM THIS RAIN WILL CAUSE CONTINUED RISES IN THE
BRANDYWINE CREEK AND ITS TRIBUTARIES OVERNIGHT.  THE CREEK IS
EXPECTED TO CREST AT 8 1/2 TO 9 1/2 FEET OVERNIGHT AT DOWNINGTOWN
AND AT 9 TO 10 FT AT CHADDS FORD.

IF YOU ARE IN THE WARNED COUNTY IN AN AREA SUBJECT TO FLOODING
MOVE TO HIGHER GROUND.  DO NOT DRIVE THRODUGH FLOOD WATERS.
CLIMBING ATOP YOUR STALLED VEHICLE WILL NOT PREVENT YOU FROM
BEING SWEPT INTO DANGEROUS STREAM CONDITIONS AS WATER LEVELS RISE.



&

SP

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 4, 6:36 PM ESTFlash Flood WarningPHIDelaware6 hr

Nearby

Flash Flood Warnings in Pennsylvania, 1993Every flash flood warning in 1993

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.