Alert archive / Pennsylvania / Flash Flood Warnings in 1995

Flash Flood Warning 10, NWS Philadelphia/Mount Holly

July 21, 1995Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 21, 1995, 5:00 AM EDT for Chester County, Pennsylvania. It was in force for 60 min.

The area

The counties it named.

The facts

Issued
Jul 21, 1995, 5:00 AM EDT (09:00 UTC)
Expired
Jul 21, 1995, 6:00 AM EDT
In force
60 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

County Chester County, PA

The radar

The Philadelphia radar (KDIX), 114 km from the middle of the area, began a volume at 09:00 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 9.0 hours before the alert went out and 182 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, Washington/Dulle, VA at 00:00Z on 1995-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 774 joules per kilogram.LCLEL10008507005003002001001 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, Washington/Dulle, VA at 00:00Z on 1995-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 35 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
774 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
1170 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
35 m²/s²
0-3 km storm-relative helicity
67 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.1

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPHL 210906
FFWPHL
PAC029-211000-
 
BULLETIN - EBS ACTIVATION REQUESTED
SEVERE THUNDERSTORM AND FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA/MOUNT HOLLY NJ
500 AM EDT FRI JUL 21 1995
 
THE NATIONAL WEATHER SERVICE IN PHILADELPHIA/MOUNT HOLLY HAS ISSUED A
SEVERE THUNDERSTORM AND FLASH FLOOD WARNING
EFFECTIVE UNTIL  600 AM EDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN  PENNSYLVANIA
 
   ...NORTHERN CHESTER COUNTY
 
AT 505 AM...NATIONAL WEATHER SERVICE RADAR SHOWED A SEVERE THUNDERSTORM
MOVING INTO CHESTER COUNTY JUST SOUTH OF HONEY BROOK.
 
THIS IS A DANGEROUS STORM.  PREPARE FOR STRONG DAMAGING WINDS...
LARGE HAIL...HEAVY RAINS AND DEADLY LIGHTNING.  SHOULD THE STORM
APPROACH MOVE INSIDE QUICKLY. DO NOT STAND NEAR WINDOWS.  MOBILE
HOMES ARE MOST VULNERABLE TO HIGH WINDS AND SHOULD BE AVOIDED.
 
HEAVY RAINS WITH THIS THUNDERSTORM MAY CAUSE FLOODING OF SMALL
STREAMS AND UNDERPASSES VERY QUICKLY.  DO NOT DRIVE YOUR CAR INTO
AREAS WHER,E THE WATER COVERS THE ROADWAY.  THE WATER MAY BE DEEPER
THAN YOU THINK.  IF CAUGHT IN RISING WATERS...ABANDON YOUR CAR
QUICKLY.  MOVE TO HIGHER GROUND.

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 21, 5:00 AM EDTSevere Thunderstorm WarningPHIChester60 min
Jul 21, 6:05 AM EDTFlash Flood WarningPHIDelaware, Montgomery, Philadelphia55 min

Nearby

Flash Flood Warnings in Pennsylvania, 1995Every flash flood warning in 1995

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; radar from the NEXRAD Level II archive.