Alert archive / Pennsylvania / Flash Flood Warnings in 2004

Flash Flood Warning 91, NWS Philadelphia/Mount Holly

September 18, 20044 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 18, 2004, 2:00 PM EDT for 4 counties in 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 outline as issued.

The facts

Issued
Sep 18, 2004, 2:00 PM EDT (18:00 UTC)
Expired
Sep 18, 2004, 5:00 PM EDT
In force
3 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Counties, with a storm outline in the text

Counties Carbon County, PA, Lehigh County, PA, Monroe County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 124 km from the middle of the area, began a volume at 18:01 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

Brookhaven, NY (KOKX), launched 12:00Z, 6.0 hours before the alert went out and 220 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 2004-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1385 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2004-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 226 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
1385 J/kg
Mixed-layer CIN
-10 J/kg
Mixed-layer LCL
550 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
226 m²/s²
0-3 km storm-relative helicity
206 m²/s²
Significant tornado parameter
1.3
Supercell composite
5.3

Open this sounding in Storm Lab

The text

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

000 
WGUS51 KPHI 181800
FFWPHI
PAC025-077-089-095-182100-
/X.NEW.KPHI.FF.W.0011.040918T1755Z-040918T2100Z/
/0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
200 PM EDT SAT SEP 18 2004

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS EXTENDED A

* FLASH FLOOD WARNING FOR...
  LEHIGH COUNTY IN EASTERN PENNSYLVANIA
  THIS INCLUDES THE CITY OF ALLENTOWN
  NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA
  THIS INCLUDES THE CITY OF BETHLEHEM
  CARBON COUNTY IN NORTHEAST PENNSYLVANIA
  MONROE COUNTY IN NORTHEAST PENNSYLVANIA

* UNTIL 500 PM EDT

* AT 152 PM EDT...FLASH FLOODING WAS REPORTED OVER THE WARNED AREA.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO WIND GAP...
  WEATHERLY...NESQUEHONING...MOUNTAINHOME...MOUNT POCONO...JIM
  THORPE...EAST STROUDSBURG...EAST BANGOR AND BRODHEADSVILLE.

ALTHOUGH RAINFALL HAS ENDED OVER THE AREA...MANY STREAMS ARE ABOVE 
FLOOD STAGE AND CONTINUING TO RISE.  THEREFORE THE FLASH FLOOD 
WWARNING REMAINS IN EFFECT.

LAT...LON 4044 7550 4060 7520 4123 7516 4089 7597

$$

AMC

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 18, 3:29 AM EDTSevere Thunderstorm WarningPHIChester31 min
Sep 18, 6:09 AM EDTFlash Flood WarningPHICarbon, Lehigh, Monroe, Northampton4 hr
Sep 18, 7:07 AM EDTFlash Flood WarningPHIBucks, Montgomery4 hr
Sep 18, 9:48 AM EDTFlash Flood WarningPHICarbon, Lehigh, Monroe, Northampton4 hr
Sep 18, 10:31 AM EDTFlash Flood WarningPHIChester, Delaware3 hr
Sep 18, 10:57 AM EDTFlash Flood WarningPHIBucks, Montgomery3 hr
Sep 18, 1:45 PM EDTFlash Flood WarningPHIBucks, Chester, Delaware, Montgomery2 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2004Every flash flood warning in 2004

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.