Alert archive / Pennsylvania / Flash Flood Warnings in 1989

Flash Flood Warning 32, NWS Philadelphia/Mount Holly

July 13, 1989Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 13, 1989, 1:31 PM EDT for Chester County, Pennsylvania. It was in force for 119 min.

The area

The counties it named.

The facts

Issued
Jul 13, 1989, 1:31 PM EDT (17:31 UTC)
Expired
Jul 13, 1989, 3:30 PM EDT
In force
119 min
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, 5.5 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 1989-07-13Temperature 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 1989-07-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 116 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
NaN m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
116 m²/s²
0-3 km storm-relative helicity
223 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 131733
FFWPHL
PAC029-131930-
 
BULLETIN - EBS ACTIVATION REQUESTED
SMALL STREAM AND URBAN FLOOD WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA PA
131 PM EDT THU JUL 13 1989
 
THE NATIONAL WEATHER SERVICE IN PHILADELPHIA HAS ISSUED A
SMALL STREAM AND URBAN FLOOD WARNING EFFECTIVE UNTIL  330 PM EDT
FOR PEOPLE IN THE FOLLOWING COUNTY...
 
IN SOUTHEAST PENNSYLVANIA
          ...CHESTER
 
AT 125 PM THE AUTOMATIC RIVER GAGE ON THE BRANDYWINE CREEK AT
DOWNINGTOWN WAS READING 6.9 FEET. FLOOD STAGE AT DOWNINGTOWN
IS 7 FEET.  THE BRANDYWINE IS EXPECTED TO SLOWLY RISE THIS
AFTERNOON...CRESTING NEAR 7.5 FEET WITHIN THE NEXT FEW HOURS.
 
FURTHER DOWNSTREAM AT CHADDS FORD...THE BRANDYWINE WILL CONTINUE
TO RISE AND CREST BELOW BANKFULL BETWEEN 5 PM AND 6 PM.  NO FLOOD
PROBLEMS ARE EXPECTED AT CHADDS FORD.
 
NO ADDITIONAL HEAVY RAINS ARE EXPECTED THIS AFTERNOON.
 
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.
 
JWH

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 13, 10:17 AM EDTFlash Flood WarningPHIMontgomery118 min

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.