Alert archive / Pennsylvania / Flash Flood Warnings in 2009

Flash Flood Warning 54, NWS Philadelphia/Mount Holly

August 22, 2009Bucks County, Northampton County, Pennsylvania; Hunterdon County, Warren County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 22, 2009, 6:21 PM EDT for Bucks County, Northampton County, Pennsylvania; Hunterdon County, Warren County, New Jersey. 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
Aug 22, 2009, 6:21 PM EDT (22:21 UTC)
Expired
Aug 22, 2009, 9:47 PM EDT
In force
3 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Hunterdon County, NJ, Warren County, NJ, Bucks County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 89 km from the middle of the area, began a volume at 22:24 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, 10.4 hours before the alert went out and 196 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 2009-08-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1060 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 2009-08-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 34 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
1060 J/kg
Mixed-layer CIN
-23 J/kg
Mixed-layer LCL
620 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
34 m²/s²
0-3 km storm-relative helicity
53 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.0

Open this sounding in Storm Lab

The text

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

000 
WGUS51 KPHI 222221
FFWPHI
NJC019-041-PAC017-095-230215-
/O.NEW.KPHI.FF.W.0054.090822T2221Z-090823T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
621 PM EDT SAT AUG 22 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA...
  THIS INCLUDES THE CITY OF EASTON...
  WESTERN HUNTERDON COUNTY IN NORTHWEST NEW JERSEY...
  WESTERN WARREN COUNTY IN NORTHWEST NEW JERSEY...
  BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 1015 PM EDT

* AT 617 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  VERY HEAVY RAIN IN VARIOUS PORTIONS OF THE WARNED AREA...WITH 1    
  INCH OF RAIN POSSIBLE IN A VERY SHORT PERIOD OF TIME.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...COUNTRY
ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS...STREAMS AND OTHER LOW
LYING AREAS ARE SUBJECT TO FLOODING.

DO NOT ATTEMPT TO CROSS WATER COVERED BRIDGES...DIPS...OR LOW WATER 
CROSSINGS. NEVER TRY TO CROSS A FLOWING STREAM...EVEN A SMALL 
ONE...ON FOOT. TO ESCAPE RISING WATER MOVE UP TO HIGHER GROUND.

&&

LAT...LON 4105 7496 4034 7488 4034 7493 4032 7493
      4030 7488 4018 7486 4016 7500 4040 7541
      4050 7541 4054 7535 4058 7541 4061 7539
      4065 7542 4078 7543

$$

JJM
1 follow-up statement
000 
WGUS71 KPHI 230147
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
947 PM EDT SAT AUG 22 2009

NJC019-041-PAC017-095-230155-
/O.CAN.KPHI.FF.W.0054.000000T0000Z-090823T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WARREN NJ-HUNTERDON NJ-NORTHAMPTON PA-BUCKS PA-
947 PM EDT SAT AUG 22 2009

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR BUCKS...
NORTHAMPTON...WESTERN HUNTERDON AND WESTERN WARREN COUNTIES...

WHILE SHOWERS ARE STILL EXPECTED OVERNIGHT...MOST OF THE HEAVY RAIN 
IS NOW OVER. THE FLASH FLOOD HAS THEREFORE BEEN CANCELLED.


LAT...LON 4105 7496 4034 7488 4034 7493 4032 7493
      4030 7488 4018 7486 4016 7500 4040 7541
      4050 7541 4054 7535 4058 7541 4061 7539
      4065 7542 4078 7543

$$

JJM

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 21, 10:14 PM EDTAreal Flood AdvisoryPHIChester3 hr
Aug 21, 10:49 PM EDTFlash Flood WarningPHIChester55 min
Aug 22, 1:40 AM EDTAreal Flood AdvisoryPHIBucks, Montgomery, Philadelphia3 hr
Aug 22, 1:51 AM EDTFlash Flood WarningPHIMontgomery, Philadelphia77 min
Aug 22, 6:03 AM EDTFlash Flood WarningPHIMontgomery, Philadelphia3 hr
Aug 22, 7:00 PM EDTFlash Flood WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia4 hr
Aug 22, 1:28 AM EDTFlash Flood WarningPHICamden, Cumberland, Gloucester, Salem4 hr
Aug 22, 3:36 AM EDTFlash Flood WarningPHISomerset4 hr
Aug 22, 4:26 AM EDTAreal Flood AdvisoryPHIAtlantic, Camden, Cape May, Cumberland, Gloucester, Salem6 hr
Aug 22, 5:42 AM EDTAreal Flood AdvisoryPHICamden, Cumberland, Gloucester, Salem3 hr
Aug 22, 9:01 AM EDTAreal Flood AdvisoryPHIAtlantic, Cape May, Cumberland3 hr
Aug 22, 6:02 PM EDTFlash Flood WarningPHIMercer4 hr
Aug 22, 6:32 PM EDTFlash Flood WarningPHICamden, Gloucester3 hr
Aug 22, 7:32 PM EDTRiver Flood WarningPHIMercer19 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2009Flash Flood Warnings in New Jersey, 2009Every flash flood warning in 2009

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.