Alert archive / New Jersey / Flash Flood Warnings in 2011

Flash Flood Warning 55, NWS Philadelphia/Mount Holly

September 8, 2011Bucks County, Montgomery County, Philadelphia County, Pennsylvania; 5 counties in New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 8, 2011, 2:26 AM EDT for Bucks County, Montgomery County, Philadelphia County, Pennsylvania; 5 counties in New Jersey. It was in force for 6 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 8, 2011, 2:26 AM EDT (06:26 UTC)
Expired
Sep 8, 2011, 8:30 AM EDT
In force
6 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Bucks County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 58 km from the middle of the area, began a volume at 06:28 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 00:00Z, 6.4 hours before the alert went out and 191 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 00:00Z on 2011-09-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 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, Brookhaven, NY at 00:00Z on 2011-09-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 123 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
4 J/kg
Mixed-layer CIN
-94 J/kg
Mixed-layer LCL
439 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
123 m²/s²
0-3 km storm-relative helicity
176 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.

612 
WGUS51 KPHI 080626
FFWPHI
NJC005-007-015-019-021-PAC017-091-101-081230-
/O.NEW.KPHI.FF.W.0055.110908T0626Z-110908T1230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
226 AM EDT THU SEP 8 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHWESTERN HUNTERDON COUNTY...
  CAMDEN COUNTY...
  EASTERN GLOUCESTER COUNTY...
  WESTERN MERCER COUNTY...
  PHILADELPHIA COUNTY...
  EASTERN MONTGOMERY COUNTY...
  BUCKS COUNTY...
  BURLINGTON COUNTY...

* UNTIL 830 AM EDT...

* AT 220 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  VERY HEAVY RAIN MOVING INTO THE AREA FROM THE SOUTHWEST. THIS      
  AIRMASS IS CAPABLE OF PRODUCING RAINFALL RATES OF ONE TO TWO       
  INCHES PER HOUR IN THE HEAVIER DOWNPOURS. THIS...IN TURN...WILL    
  PRODUCE RAPID RUNOFF GIVEN THE ALREADY SATURATED CONDITIONS.       
  ROADWAY AND POOR DRAINAGE FLOODING CAN EXPECTED...ALONG WITH       
  RENEWED RISES ON SMALL STREAMS AND CREEKS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE THROUGH FLOODED ROADWAYS...THE WATER MAY BE DEEPER THAN 
YOU THINK.

&&

LAT...LON 3991 7454 3953 7497 4042 7551 4062 7520
      4059 7518 4064 7510 4017 7459 4018 7460
      4016 7461 3997 7450

$$

JJM

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 7, 8:11 PM EDTFlash Flood WarningPHIBerks4 hr
Sep 7, 8:24 PM EDTAreal Flood WarningPHIMontgomery6 hr
Sep 7, 9:32 PM EDTSpecial Weather StatementPHIBerks118 min
Sep 7, 9:38 PM EDTRiver Flood WarningPHIMontgomery13 hr
Sep 7, 11:32 PM EDTAreal Flood AdvisoryPHIBucks, Carbon, Lehigh, Monroe, Northampton3 hr
Sep 8, 12:13 AM EDTAreal Flood WarningPHIBerks24 hr
Sep 8, 1:25 AM EDTFlash Flood WarningPHIDelaware, Montgomery, Philadelphia7 hr
Sep 8, 3:15 AM EDTFlash Flood WarningPHILehigh, Monroe, Northampton6 hr
Sep 8, 3:41 AM EDTRiver Flood WarningPHILehigh, Northampton7 hr
Sep 8, 3:49 AM EDTRiver Flood WarningPHIMonroe7 hr
Sep 8, 5:30 AM EDTCoastal Flood WatchPHIDelaware, Philadelphia6 hr
Sep 8, 5:30 AM EDTCoastal Flood AdvisoryPHIDelaware, Philadelphia8 hr
Sep 8, 5:48 AM EDTRiver Flood WarningPHIMonroe34 hr
Sep 8, 8:36 AM EDTAreal Flood WarningPHIBucks, Delaware, Montgomery, Philadelphia16 hr
Sep 8, 9:32 AM EDTAreal Flood WarningPHIBerks, Bucks, Carbon, Chester, Lehigh, Montgomery15 hr
Sep 8, 11:12 AM EDTRiver Flood WarningPHIMonroe, Northampton8 hr
Sep 8, 11:42 AM EDTCoastal Flood WarningPHIDelaware, Philadelphia15 hr
Sep 8, 3:14 PM EDTRiver Flood WarningPHILehigh, Northampton13 hr
Sep 7, 9:42 PM EDTRiver Flood WarningPHIMorris42 hr
Sep 8, 4:01 AM EDTRiver Flood WarningPHIMorris, Somerset7 hr
Sep 8, 4:01 AM EDTRiver Flood WarningPHIBergen, Morris, Passaic36 hr
Sep 8, 4:01 AM EDTRiver Flood WarningPHISomerset18 hr
Sep 8, 4:01 AM EDTRiver Flood WarningPHIMiddlesex, Somerset36 hr
Sep 8, 4:01 AM EDTRiver Flood WarningPHIMercer18 hr
Sep 8, 4:01 AM EDTRiver Flood WarningPHIBurlington15 hr
Sep 8, 4:58 AM EDTFlash Flood WarningPHIMiddlesex, Monmouth, Ocean3 hr
Sep 8, 5:30 AM EDTCoastal Flood AdvisoryPHICumberland, Salem17 hr
Sep 8, 9:53 AM EDTAreal Flood WarningPHIHunterdon, Mercer, Morris, Somerset24 hr
Sep 8, 9:58 AM EDTAreal Flood WarningPHIMorris7 days
Sep 8, 12:36 PM EDTFlash Flood WarningPHICumberland, Salem2 hr
Sep 8, 1:15 PM EDTSpecial Weather StatementPHICumberland60 min
Sep 8, 5:08 PM EDTRiver Flood WarningPHIMorris, Somerset16 hr

Nearby

Flash Flood Warnings in New Jersey, 2011Flash Flood Warnings in Pennsylvania, 2011Every flash flood warning in 2011

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.