Alert archive / Pennsylvania / Flash Flood Warnings in 2001

Flash Flood Warning 46, NWS Philadelphia/Mount Holly

August 11, 2001Lehigh County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 11, 2001, 2:45 PM EDT for Lehigh County, Pennsylvania. It was in force for 90 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 11, 2001, 2:45 PM EDT (18:45 UTC)
Expired
Aug 11, 2001, 4:15 PM EDT
In force
90 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

County Lehigh County, PA

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 6.8 hours before the alert went out and 231 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 2001-08-11Temperature 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 2001-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -25 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
1451 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
-25 m²/s²
0-3 km storm-relative helicity
59 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.8

Open this sounding in Storm Lab

The text

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

000 
WGUS51 KPHI 111847
FFWPHI
PAC077-112015-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
245 PM EDT SAT AUG 11 2001

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS CONTINUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN LEHIGH COUNTY IN EASTERN PENNSYLVANIA

* UNTIL 415 PM EDT.

* AT 230 PM EDT...EMERGENCY MANAGEMENT OFFICIALS REPORTED THAT
  FLOODING CONTINUES IN THE SOUTH ALLENTOWN AREA...SALISBURY TWP... 
  AND NEARBY AREAS.

RADAR INDICATES THAT THE RAIN HAS DIMINSHED FOR THE TIME BEING...SO 
FLOOD WATERS SHOULD BEGIN TO SUBSIDE.  HOWEVER SOME FLOODING IS 
LIKELY TO CONTINUE THROUGH THE AFTERNOON.

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING OF SMALL
CREEKS AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES
AS WELL AS POOR DRAINAGE AREAS AND LOW LYING SPOTS.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS
IMMINENT. MOST FLASH FLOOD DEATHS OCCUR IN AUTOMOBILES. DO NOT DRIVE
YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE ROADWAY. THE WATER
DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS SAFELY. VEHICLES
CAUGHT IN RISING WATER SHOULD BE ABANDONED QUICKLY. MOVE TO HIGHER
GROUND.

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

$$

LAT...LON 4067 7551 4054 7538 4045 7551 4056 7568

AMC

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 10:17 AM EDTFlash Flood WarningPHIBerks3 hr
Aug 11, 11:20 AM EDTFlash Flood WarningPHIBucks3 hr
Aug 11, 11:35 AM EDTFlash Flood WarningPHILehigh3 hr
Aug 11, 12:55 PM EDTFlash Flood WarningPHIBerks3 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2001Every flash flood warning in 2001

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.