Alert archive / Pennsylvania / Flash Flood Warnings in 1993

Flash Flood Warning 5, NWS Philadelphia/Mount Holly

March 24, 1993Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Mar 24, 1993, 5:51 AM EST for Chester County, Pennsylvania. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued
Mar 24, 1993, 5:51 AM EST (10:51 UTC)
Expired
Mar 24, 1993, 2:00 PM 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 00:00Z, 10.9 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 00:00Z on 1993-03-24Temperature 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 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 1993-03-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 216 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
889 m above ground
0-6 km bulk shear
51 kt
0-1 km storm-relative helicity
216 m²/s²
0-3 km storm-relative helicity
424 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 241057 COR
FFWPHL
PAC029-241900-

BULLETIN - EBS ACTIVATION REQUESTED
FLOOD WARNING...CORRECTION
NATIONAL WEATHER SERVICE PHILADELPHIA PA
551 AM EST WED MAR 24 1993

THE NATIONAL WEATHER SERVICE IN PHILADELPHIA HAS ISSUED A
FLOOD WARNING EFFECTIVE UNTIL  200 PM EST
FOR PEOPLE IN THE FOLLOWING LOCATION...

IN SOUTHEAST PENNSYLVANIA

   ...CHESTER COUNTY

PERSISTENT RAINFALL OVERNIGHT HAS CAUSED THE BRANDYWINE CREEK TO RISE
STEADILY DURING THE LAST SEVERAL HOURS. AT 515 AM EST THE RIVER GUAGE
AT CHADDS FORD INDICATED A WATER LEVEL OF 7.74 FT...STILL BELOW THE
FLOOD STAGE OF 8.00 FT.  HOWEVER...THE CREEK WAS RISING NEARLY A
HALF-FOOT PER HOUR AND SHOULD RISE OUT OF ITS BANKS BETWEEN 615 AM AND
700 AM THIS MORNING.

THE BRANDYWINE CREEK IS EXPECTED TO CREST AT CHADDS FORD LATER THIS
MORNING BETWEEN 10 AND 11 FEET.

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.

PERSONS LIVING NEAR THE BRANDYWINE CREEK SHOULD KEEP A SHARP LOOKOUT
FOR RISING WATER AND MOVE TO HIGHER GROUND IF NECESSARY.
0
BE ESPECIALLY CAUTIOUS EARLY THIS MORNING WHILE IT IS STILL DARK AND
MORE DIFFICULT TO SEE WATER FLOWING OVER THE ROAD.

CORRECTION FOR PARAGRAPH STRUCTURE ONLY

DCY

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 24, 7:30 AM ESTFlash Flood WarningPHIBucks6 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.