Alert archive / New Jersey / Flash Flood Warnings in 2015

Flash Flood Warning 49, NWS Philadelphia/Mount Holly

August 21, 20155 counties in New Jersey; Bucks County, Montgomery County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 21, 2015, 12:46 AM EDT for 5 counties in New Jersey; Bucks County, Montgomery County, Philadelphia County, Pennsylvania. It was in force for 4 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 21, 2015, 12:46 AM EDT (04:46 UTC)
Expired
Aug 21, 2015, 4:45 AM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Burlington County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Somerset County, NJ, Bucks County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 50 km from the middle of the area, began a volume at 04:46 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.

What was reported inside it

TimeReportWhereRemark
Aug 21, 1:31 AM EDTFLOODAbington Twp, PALOCALIZED FLOODING ON ROADWAYS

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 4.8 hours before the alert went out and 180 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 2015-08-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 178 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 00:00Z on 2015-08-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 72 square meters per square second.1939Sfc1 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
178 J/kg
Mixed-layer CIN
-11 J/kg
Mixed-layer LCL
657 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
72 m²/s²
0-3 km storm-relative helicity
121 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.

385 
WGUS51 KPHI 210446
FFWPHI
NJC005-021-023-025-035-PAC017-091-101-210845-
/O.NEW.KPHI.FF.W.0049.150821T0446Z-150821T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1246 AM EDT FRI AUG 21 2015

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ  HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  MERCER COUNTY IN CENTRAL NEW JERSEY...
  SOUTHWESTERN MONMOUTH COUNTY IN CENTRAL NEW JERSEY...
  SOUTHWESTERN SOMERSET COUNTY IN NORTHERN NEW JERSEY...
  SOUTHWESTERN MIDDLESEX COUNTY IN NORTHERN NEW JERSEY...
  NORTHWESTERN BURLINGTON COUNTY IN SOUTHERN NEW JERSEY...
  SOUTHEASTERN BUCKS COUNTY IN SOUTHEASTERN PENNSYLVANIA...
  SOUTHEASTERN MONTGOMERY COUNTY IN SOUTHEASTERN PENNSYLVANIA...
  NORTHERN PHILADELPHIA COUNTY IN SOUTHEASTERN PENNSYLVANIA...

* UNTIL 445 AM EDT
    
* AT 1245 AM EDT...DOPPLER RADAR INDICATED A THUNDERSTORM PRODUCING 
  HEAVY RAIN ACROSS THE WARNED AREA. 1.5 INCHES OF RAIN HAVE FALLEN 
  WITH AN ADDITIONAL INCH TO INCH AND A HALF POSSIBLE WITHIN THE 
  NEXT HOUR. FLASH FLOODING IS EXPECTED TO BEGIN SHORTLY.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  PHILADELPHIA...TRENTON...BENSALEM...EAST BRUNSWICK...SOUTH
  BRUNSWICK...NORTH BRUNSWICK...EWING...WILLINGBORO...PRINCETON...
  FLORENCE...BURLINGTON...BRISTOL...RIVERSIDE...HIGHTSTOWN...
  JENKINTOWN...NARBERTH...BORDENTOWN...CRANBURY...PENNINGTON AND
  BEVERLY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO HIGHER GROUND NOW. ACT QUICKLY TO PROTECT YOUR LIFE.

TURN AROUND...DON'T DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

&&

LAT...LON 4008 7455 4005 7454 4000 7526 4014 7528
      4014 7511 4028 7502 4036 7504 4038 7496
      4034 7494 4035 7486 4038 7487 4038 7481
      4041 7481 4043 7475 4046 7447 4014 7445

$$

HEAVENER
2 follow-up statements
758 
WGUS71 KPHI 210757
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
357 AM EDT FRI AUG 21 2015

NJC005-021-023-025-035-PAC017-091-101-210845-
/O.CON.KPHI.FF.W.0049.000000T0000Z-150821T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MERCER NJ-MONMOUTH NJ-SOMERSET NJ-MIDDLESEX NJ-BURLINGTON NJ-
BUCKS PA-MONTGOMERY PA-PHILADELPHIA PA-
357 AM EDT FRI AUG 21 2015

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 445 AM EDT FOR
MERCER...SOUTHWESTERN MONMOUTH...SOUTHWESTERN SOMERSET...SOUTHWESTERN
MIDDLESEX...NORTHWESTERN BURLINGTON...SOUTHEASTERN BUCKS...
SOUTHEASTERN MONTGOMERY AND NORTHERN PHILADELPHIA COUNTIES...

AT 342 AM EDT...FLASH FLOODING IS LIKELY OR ALREADY OCCURRING IN 
PORTIONS OF SOUTHEASTERN MONTGOMERY COUNTY INTO NORTH CENTRAL 
PHILADELPHIA COUNTY.

SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
PHILADELPHIA...TRENTON...BENSALEM...EAST BRUNSWICK...SOUTH
BRUNSWICK...NORTH BRUNSWICK...EWING...WILLINGBORO...PRINCETON...
FLORENCE...BURLINGTON...BRISTOL...RIVERSIDE...HIGHTSTOWN...
JENKINTOWN...NARBERTH...BORDENTOWN...CRANBURY...PENNINGTON AND
BEVERLY.

FLOOD WATERS ARE MOVING DOWN THE WISSAHICKON CREEK FROM FORT 
WASHINGTON TO PHILADELPHIA. THE FLOOD CREST IS EXPECTED TO REACH 
PHILADELPHIA ON THE WISSAHICKON BY 430AM.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO HIGHER GROUND NOW. ACT QUICKLY TO PROTECT YOUR LIFE.

TURN AROUND...DON'T DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

&&

LAT...LON 4008 7455 4005 7454 4000 7526 4014 7528
      4014 7511 4028 7502 4036 7504 4038 7496
      4034 7494 4035 7486 4038 7487 4038 7481
      4041 7481 4043 7475 4046 7447 4014 7445

$$

HEAVENER
788 
WGUS71 KPHI 210837
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
437 AM EDT FRI AUG 21 2015

NJC005-021-023-025-035-PAC017-091-101-210847-
/O.EXP.KPHI.FF.W.0049.000000T0000Z-150821T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MERCER NJ-MONMOUTH NJ-SOMERSET NJ-MIDDLESEX NJ-BURLINGTON NJ-
BUCKS PA-MONTGOMERY PA-PHILADELPHIA PA-
437 AM EDT FRI AUG 21 2015

...THE FLASH FLOOD WARNING FOR MERCER...SOUTHWESTERN MONMOUTH...
SOUTHWESTERN SOMERSET...SOUTHWESTERN MIDDLESEX...NORTHWESTERN
BURLINGTON...SOUTHEASTERN BUCKS...SOUTHEASTERN MONTGOMERY AND
NORTHERN PHILADELPHIA COUNTIES WILL EXPIRE AT 445 AM EDT...

FLOOD WATERS HAVE RECEDED...AND ARE NO LONGER EXPECTED TO POSE A
THREAT TO LIFE OR PROPERTY. PLEASE CONTINUE TO HEED ANY ROAD
CLOSURES.

LAT...LON 4008 7455 4005 7454 4000 7526 4014 7528
      4014 7511 4028 7502 4036 7504 4038 7496
      4034 7494 4035 7486 4038 7487 4038 7481
      4041 7481 4043 7475 4046 7447 4014 7445

$$

HEAVENER

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 20, 11:18 PM EDTSpecial Weather StatementPHIHunterdon, Mercer57 min
Aug 20, 11:35 PM EDTAreal Flood AdvisoryPHIBurlington, Hunterdon, Mercer, Middlesex, Somerset4 hr
Aug 21, 12:51 AM EDTSpecial Weather StatementPHIMercer39 min
Aug 21, 1:02 AM EDTSevere Thunderstorm WarningPHIBurlington, Mercer, Middlesex, Monmouth, Ocean37 min
Aug 21, 1:38 AM EDTAreal Flood AdvisoryPHIAtlantic, Cape May, Cumberland, Gloucester, Salem4 hr
Aug 21, 2:30 AM EDTAreal Flood AdvisoryPHISussex4 hr
Aug 21, 3:10 AM EDTFlash Flood WarningPHICape May4 hr
Aug 21, 4:31 AM EDTAreal Flood AdvisoryPHIMiddlesex, Monmouth, Ocean4 hr
Aug 20, 9:08 PM EDTAreal Flood AdvisoryPHIBerks, Carbon, Lehigh, Monroe, Northampton4 hr
Aug 20, 10:32 PM EDTAreal Flood AdvisoryPHIBerks, Bucks, Chester, Lehigh, Montgomery, Northampton4 hr
Aug 20, 10:55 PM EDTFlash Flood WarningPHIBerks, Bucks, Chester, Lehigh, Montgomery4 hr
Aug 21, 5:38 AM EDTAreal Flood WarningPHIPhiladelphia112 min

Nearby

Flash Flood Warnings in New Jersey, 2015Flash Flood Warnings in Pennsylvania, 2015Every flash flood warning in 2015

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.