Alert archive / Pennsylvania / Flash Flood Warnings in 1999

Flash Flood Warning 32, NWS Philadelphia/Mount Holly

September 9, 1999Berks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 9, 1999, 7:17 PM 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 9, 1999, 7:17 PM EDT (23:17 UTC)
Expired
Sep 9, 1999, 10:15 PM EDT
In force
3 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

County Berks County, PA

The radar

The Philadelphia radar (KDIX), 139 km from the middle of the area, began a volume at 23:17 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 12:00Z, 11.3 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 12:00Z on 1999-09-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 60 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 12:00Z on 1999-09-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 32 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
60 J/kg
Mixed-layer CIN
-110 J/kg
Mixed-layer LCL
900 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
32 m²/s²
0-3 km storm-relative helicity
70 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPHL 092317
FFWPHL
PAC011-089-095-100215-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
717 PM EDT THU SEP 9 1999

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

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

* UNTIL 1015 PM EDT.

* HEAVY RAIN CONTINUES TO FALL OVER THE AREA. AT 715 PM EDT NATIONAL
  WEATHER SERVICE DOPPLER RADAR INDICATED UP TO 4 INCHES OF
  RAIN HAD FALLEN IN SOME LOCATIONS DURING THE PAST FEW HOURS.
  DOPPLER RADAR SHOWED MORE HEAVY RAIN MOVING INTO THE REGION
  FROM THE SOUTHWEST.

  WATER LEVELS ON SMALL STREAMS IN THE AREA WILL RISE RAPIDLY.
  FLOODING OF POOR DRAINAGE AREAS WILL ALSO OCCUR AS A RESULT OF
  THIS RAIN.

  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
  JJM/AMC

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 9, 5:09 PM EDTSevere Thunderstorm WarningPHIBerks51 min
Sep 9, 7:17 PM EDTFlash Flood WarningPHIMonroe, Northampton3 hr

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; radar from the NEXRAD Level II archive.