Alert archive / Pennsylvania / Flash Flood Warnings in 1999

Flash Flood Warning 30, NWS Philadelphia/Mount Holly

September 7, 1999Berks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 7, 1999, 4:10 AM EDT for Berks County, Pennsylvania. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Sep 7, 1999, 4:10 AM EDT (08:10 UTC)
Expired
Sep 7, 1999, 6:40 AM EDT
In force
3 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

County Berks County, PA

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 8.2 hours before the alert went out and 206 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 1999-09-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 35 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, Washington/Dulle, VA at 00:00Z on 1999-09-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 140 square meters per square second.1939Sfc1 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
35 J/kg
Mixed-layer CIN
-19 J/kg
Mixed-layer LCL
617 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
140 m²/s²
0-3 km storm-relative helicity
142 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 070809
FFWPHL
PAC011-071040-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
410 AM EDT TUE SEP 7 1999

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  BERKS COUNTY IN PENNSYLVANIA.

* UNTIL 640 AM EDT.

* AT 405 AM EDT...NATIONAL WEATHER SERVICE RADAR SHOWED OVER 2
INCHES OF RAIN HAS FALLEN JUST NORTH OF HAMBURG. HEAVY RAIN
FELL IN THE SAME AREA SUNDAY NIGHT. ALTHOUGH MOST OF THE HEAVY
RAIN HAS FALLEN...AN ADDITIONAL 1/4 TO 1/2 INCH COULD STILL
FALL IN THE NEXT HOUR OR TWO.

  BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
  DANGERS OF FLASH FLOODING. IF FLOODING IS OBSERVED...ACT QUICKLY.
  MOVE UP TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS SUBJECT TO
  FLOODING WHEN WATER BEGINS RISING.

  FOR THE LATEST STORM INFORMATION...PLEASE TUNE TO NOAA WEATHER
  RADIO...YOUR LOCAL RADIO OR TELEVISION STATIONS...OR YOUR CABLE
  TELEVISION OUTLET.

  .END
  RNS

Nearby

Flash Flood Warnings in Pennsylvania, 1999Every flash flood warning in 1999

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.