Alert archive / Pennsylvania / Flash Flood Warnings in 1999

Flash Flood Warning 7, NWS Philadelphia/Mount Holly

January 18, 19994 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jan 18, 1999, 6:20 PM EST for 4 counties in Pennsylvania. It was in force for 4 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
Jan 18, 1999, 6:20 PM EST (23:20 UTC)
Expired
Jan 18, 1999, 10:30 PM EST
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

Counties Berks County, PA, Lehigh County, PA, Montgomery County, PA, Northampton County, PA

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 11.3 hours before the alert went out and 230 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, Brookhaven, NY at 12:00Z on 1999-01-18Temperature 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, Brookhaven, NY at 12:00Z on 1999-01-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 242 square meters per square second.1939587897Sfc1 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
984 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
242 m²/s²
0-3 km storm-relative helicity
241 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 182322
FFWPHL
PAC011-077-091-095-190330-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
620 PM EST MON JAN 18 1999

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  BERKS COUNTY IN PENNSYLVANIA
  LEHIGH COUNTY IN PENNSYLVANIA
  NORTHAMPTON COUNTY IN PENNSYLVANIA
  MONTGOMERY COUNTY IN PENNSYLVANIA

* UNTIL 1030 PM EST

AT 615 PM COUNTY EMERGENCY MANAGEMENT PERSONNEL REPORTED CONTINUED
RUNOFF FROM THE HEAVY SHOWERS OF THIS AFTERNOON. IN BERKS COUNTY
PENNSYLVANIA WATER WAS REPORTED TO BE OVERFLOWING DAUBERVILLE DAM
IN CENTER TOWNSHIP. ELSEWHERE FLOOD GAGES SHOWED MANY STREAMS
NEARING FLOOD STAGE IN LEHIGH NORTHAMPTON AND MONTGOMERY COUNTIES
IN EASTERN PENNSYLVANIA.

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 SUB,JECT 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.





&

The office that day

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

IssuedProductOfficeCountiesLasted
Jan 18, 3:15 PM ESTFlash Flood WarningPHIBerks3 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.