Alert archive / New Jersey / Flash Flood Watches in 2015

Flash Flood Watch 5, NWS Philadelphia/Mount Holly

August 20, 20154 states

NWS Philadelphia/Mount Holly issued this flash flood watch at Aug 20, 2015, 2:46 PM EDT for 4 states. It was in force for 13 hr.

The area

The counties it named.

The facts

Issued
Aug 20, 2015, 2:46 PM EDT (18:46 UTC)
Expired
Aug 21, 2015, 3:39 AM EDT
In force
13 hr
Issued by
NWS Philadelphia/Mount Holly
Flood severity
None
All 24 counties

New Castle County, DE, Cecil County, MD, Kent County, MD, Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Morris County, NJ, Salem County, NJ, Somerset County, NJ, Sussex County, NJ, Warren County, NJ, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 77 km from the middle of the area, began a volume at 18:49 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, 6.8 hours before the alert went out and 210 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 2015-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 227 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 2015-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -12 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
227 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
637 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
-12 m²/s²
0-3 km storm-relative helicity
17 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.

950 
WGUS61 KPHI 201846
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
FLOOD WATCH
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
246 PM EDT THU AUG 20 2015

NJZ001-007-PAZ054-055-060>062-210300-
/O.NEW.KPHI.FF.A.0005.150820T1846Z-150821T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUSSEX-WARREN-CARBON-MONROE-BERKS-LEHIGH-NORTHAMPTON-
INCLUDING THE CITIES OF...NEWTON...WASHINGTON...JIM THORPE...
STROUDSBURG...READING...ALLENTOWN...BETHLEHEM...EASTON
246 PM EDT THU AUG 20 2015

...FLASH FLOOD WATCH IN EFFECT THROUGH LATE TONIGHT...

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY HAS ISSUED A

* FLASH FLOOD WATCH FOR PORTIONS OF NORTHERN NEW JERSEY AND 
  PENNSYLVANIA...INCLUDING THE FOLLOWING IN NORTHERN ...NEW 
  JERSEY...SUSSEX AND WARREN. IN PENNSYLVANIA...BERKS...CARBON...
  LEHIGH...MONROE AND NORTHAMPTON. 

* THROUGH LATE TONIGHT

* WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS ARE MOVING IN FROM
  THE SOUTHWEST THIS AFTERNOON. SOME OF THE HEAVIER SHOWERS AND
  THUNDERSTORMS WILL BE CAPABLE OF PRODUCING RAINFALL RATES IN
  EXCESS OF 2 INCHES PER HOUR. WITH MULTIPLE ROUNDS OF HEAVY RAIN
  POSSIBLE THIS AFTERNOON AND TONIGHT, LOCALLY HIGHER RAINFALL
  AMOUNTS OF 3 TO 4 INCHES ARE POSSIBLE IN SPOTS.

* POOR DRAINAGE ROADWAY FLOODING WILL BE LIKELY WHERE THE
  HEAVIEST RAINS FALL. THERE IS ALSO THE POTENTIAL FOR FLASH
  FLOODING ALONG SMALLER STREAMS, CREEKS, AND URBANIZED AREAS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO A RAPID RISE OF WATER TO DANGEROUS LEVELS. FLASH FLOODING IS A
VERY DANGEROUS SITUATION.

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.

&&

$$

DEZ001-MDZ008-012-NJZ008>010-012-015>019-PAZ070-071-101>106-
210300-
/O.NEW.KPHI.FF.A.0005.150820T1846Z-150821T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
NEW CASTLE-CECIL-KENT MD-MORRIS-HUNTERDON-SOMERSET-MIDDLESEX-
MERCER-SALEM-GLOUCESTER-CAMDEN-NORTHWESTERN BURLINGTON-DELAWARE-
PHILADELPHIA-WESTERN CHESTER-EASTERN CHESTER-WESTERN MONTGOMERY-
EASTERN MONTGOMERY-UPPER BUCKS-LOWER BUCKS-
INCLUDING THE CITIES OF...WILMINGTON...ELKTON...CHESTERTOWN...
MORRISTOWN...FLEMINGTON...SOMERVILLE...NEW BRUNSWICK...TRENTON...
PENNSVILLE...GLASSBORO...CAMDEN...CHERRY HILL...MOORESTOWN...
MOUNT HOLLY...MEDIA...PHILADELPHIA...HONEY BROOK...OXFORD...
WEST CHESTER...KENNETT SQUARE...COLLEGEVILLE...POTTSTOWN...
NORRISTOWN...LANSDALE...CHALFONT...PERKASIE...MORRISVILLE...
DOYLESTOWN
246 PM EDT THU AUG 20 2015

...FLASH FLOOD WATCH IN EFFECT THROUGH FRIDAY MORNING...

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY HAS ISSUED A

* FLASH FLOOD WATCH FOR PORTIONS OF NORTHERN DELAWARE... 
  NORTHEAST MARYLAND...NEW JERSEY AND SOUTHEAST PENNSYLVANIA... 
  INCLUDING THE FOLLOWING IN NORTHERN ...DELAWARE...NEW CASTLE. 
  IN NORTHEAST MARYLAND...CECIL AND KENT MD. IN NEW JERSEY... 
  CAMDEN...GLOUCESTER...HUNTERDON...MERCER...MIDDLESEX... 
  MORRIS...NORTHWESTERN BURLINGTON...SALEM AND SOMERSET. IN 
  SOUTHEAST PENNSYLVANIA...DELAWARE...EASTERN CHESTER...EASTERN 
  MONTGOMERY...LOWER BUCKS...PHILADELPHIA...UPPER BUCKS... 
  WESTERN CHESTER AND WESTERN MONTGOMERY. 

* THROUGH FRIDAY MORNING

* NUMEROUS SHOWERS AND EMBEDDED THUNDERSTORMS WILL MOVE IN FROM
  THE SOUTHWEST DURING THE MID AND LATE AFTERNOON. SOME OF THE
  HEAVIER SHOWERS AND THUNDERSTORMS WILL BE CAPABLE OF PRODUCING
  RAINFALL RATES IN EXCESS OF 2 INCHES PER HOUR.

* POOR DRAINAGE ROADWAY FLOODING WILL BE LIKELY WHERE THE
  HEAVIEST RAINS FALL. THERE IS ALSO THE POTENTIAL FOR FLASH
  FLOODING ALONG SMALLER STREAMS, CREEKS, AND URBANIZED AREAS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO A RAPID RISE OF WATER TO DANGEROUS LEVELS. FLASH FLOODING IS A
VERY DANGEROUS SITUATION.

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.

&&

$$
2 follow-up statements
160 
WGUS61 KPHI 210152
FFAPHI

FLOOD WATCH
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
952 PM EDT THU AUG 20 2015

NJZ001-007-PAZ054-055-060>062-210800-
/O.CON.KPHI.FF.A.0005.000000T0000Z-150821T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUSSEX-WARREN-CARBON-MONROE-BERKS-LEHIGH-NORTHAMPTON-
INCLUDING THE CITIES OF...NEWTON...WASHINGTON...JIM THORPE...
STROUDSBURG...READING...ALLENTOWN...BETHLEHEM...EASTON
952 PM EDT THU AUG 20 2015

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 4 AM EDT FRIDAY...

THE FLASH FLOOD WATCH CONTINUES FOR

* PORTIONS OF NORTHERN NEW JERSEY AND PENNSYLVANIA...INCLUDING 
  THE FOLLOWING IN NORTHERN ...NEW JERSEY...SUSSEX AND WARREN. 
  IN PENNSYLVANIA...BERKS...CARBON...LEHIGH...MONROE AND 
  NORTHAMPTON. 

* UNTIL 4 AM EDT FRIDAY

* WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS ARE MOVING THROUGH
  THE AREA THIS EVENING. SOME OF THE HEAVIER SHOWERS AND
  THUNDERSTORMS WILL BE CAPABLE OF PRODUCING RAINFALL RATES UP TO
  2 INCHES PER HOUR. LOCALLY HIGHER RAINFALL AMOUNTS OF 3 TO 5
  INCHES ARE POSSIBLE IN SPOTS, ESPECIALLY IN BERKS COUNTY. THE
  RAIN WILL END FROM WEST TO EAST LATE THIS EVENING AND OVERNIGHT.

* POOR DRAINAGE ROADWAY FLOODING WILL BE LIKELY WHERE THE HEAVIEST
  RAINS FALL. THERE IS ALSO THE POTENTIAL FOR LOCALIZED FLASH
  FLOODING ALONG SMALLER STREAMS...CREEKS AND URBANIZED AREAS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO A RAPID RISE OF WATER TO DANGEROUS LEVELS. FLASH FLOODING IS A
VERY DANGEROUS SITUATION.

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.

&&

$$

DEZ001-MDZ008-012-NJZ008>010-012-015>019-PAZ070-071-101>106-
211000-
/O.CON.KPHI.FF.A.0005.000000T0000Z-150821T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
NEW CASTLE-CECIL-KENT MD-MORRIS-HUNTERDON-SOMERSET-MIDDLESEX-
MERCER-SALEM-GLOUCESTER-CAMDEN-NORTHWESTERN BURLINGTON-DELAWARE-
PHILADELPHIA-WESTERN CHESTER-EASTERN CHESTER-WESTERN MONTGOMERY-
EASTERN MONTGOMERY-UPPER BUCKS-LOWER BUCKS-
INCLUDING THE CITIES OF...WILMINGTON...ELKTON...CHESTERTOWN...
MORRISTOWN...FLEMINGTON...SOMERVILLE...NEW BRUNSWICK...TRENTON...
PENNSVILLE...GLASSBORO...CAMDEN...CHERRY HILL...MOORESTOWN...
MOUNT HOLLY...MEDIA...PHILADELPHIA...HONEY BROOK...OXFORD...
WEST CHESTER...KENNETT SQUARE...COLLEGEVILLE...POTTSTOWN...
NORRISTOWN...LANSDALE...CHALFONT...PERKASIE...MORRISVILLE...
DOYLESTOWN
952 PM EDT THU AUG 20 2015

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 9 AM EDT FRIDAY...

THE FLASH FLOOD WATCH CONTINUES FOR

* PORTIONS OF NORTHERN DELAWARE...NORTHEAST MARYLAND...NEW 
  JERSEY AND SOUTHEAST PENNSYLVANIA...INCLUDING THE FOLLOWING IN 
  NORTHERN ...DELAWARE...NEW CASTLE. IN NORTHEAST MARYLAND... 
  CECIL AND KENT MD. IN NEW JERSEY...CAMDEN...GLOUCESTER... 
  HUNTERDON...MERCER...MIDDLESEX...MORRIS...NORTHWESTERN 
  BURLINGTON...SALEM AND SOMERSET. IN SOUTHEAST PENNSYLVANIA... 
  DELAWARE...EASTERN CHESTER...EASTERN MONTGOMERY...LOWER 
  BUCKS...PHILADELPHIA...UPPER BUCKS...WESTERN CHESTER AND 
  WESTERN MONTGOMERY. 

* UNTIL 9 AM EDT FRIDAY

* NUMEROUS SHOWERS AND EMBEDDED THUNDERSTORMS WILL MOVE THROUGH
  THE AREA THIS EVENING BEFORE ENDING FROM WEST TO EAST OVERNIGHT.
  SOME OF THE HEAVIER SHOWERS AND THUNDERSTORMS WILL BE CAPABLE OF
  PRODUCING RAINFALL RATES UP TO 2 INCHES PER HOUR.

* POOR DRAINAGE ROADWAY FLOODING WILL BE LIKELY WHERE THE HEAVIEST
  RAINS FALL. THERE IS ALSO THE POTENTIAL FOR LOCALIZED FLASH
  FLOODING ALONG SMALLER STREAMS...CREEKS AND URBANIZED AREAS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO A RAPID RISE OF WATER TO DANGEROUS LEVELS. FLASH FLOODING IS A
VERY DANGEROUS SITUATION.

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.

&&

$$
380 
WGUS61 KPHI 210739
FFAPHI

FLOOD WATCH
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
339 AM EDT FRI AUG 21 2015


DEZ001-MDZ008-012-NJZ008>010-012-015>019-PAZ070-071-101>106-
210845-
/O.CAN.KPHI.FF.A.0005.000000T0000Z-150821T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
NEW CASTLE-CECIL-KENT MD-MORRIS-HUNTERDON-SOMERSET-MIDDLESEX-
MERCER-SALEM-GLOUCESTER-CAMDEN-NORTHWESTERN BURLINGTON-DELAWARE-
PHILADELPHIA-WESTERN CHESTER-EASTERN CHESTER-WESTERN MONTGOMERY-
EASTERN MONTGOMERY-UPPER BUCKS-LOWER BUCKS-
INCLUDING THE CITIES OF...WILMINGTON...ELKTON...CHESTERTOWN...
MORRISTOWN...FLEMINGTON...SOMERVILLE...NEW BRUNSWICK...TRENTON...
PENNSVILLE...GLASSBORO...CAMDEN...CHERRY HILL...MOORESTOWN...
MOUNT HOLLY...MEDIA...PHILADELPHIA...HONEY BROOK...OXFORD...
WEST CHESTER...KENNETT SQUARE...COLLEGEVILLE...POTTSTOWN...
NORRISTOWN...LANSDALE...CHALFONT...PERKASIE...MORRISVILLE...
DOYLESTOWN
339 AM EDT FRI AUG 21 2015

...FLASH FLOOD WATCH IS CANCELLED...

THE FLASH FLOOD WATCH FOR PORTIONS OF NORTHERN DELAWARE...
NORTHEAST MARYLAND...NEW JERSEY AND SOUTHEAST PENNSYLVANIA HAS
BEEN CANCELLED. MOST OF THE HEAVY RAIN THREAT HAS SHIFTED EAST.
THOUGH THERE REMAINS ONE LINGERING LINE OF HEAVER RAIN IN CENTRAL
AND SOUTHERN NEW JERSEY. ANY LINGERING HEAVY RAIN THREAT SHOULD BE
ISOLATED.

$$

NJZ001-007-PAZ054-055-060>062-210845-
/O.CAN.KPHI.FF.A.0005.000000T0000Z-150821T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUSSEX-WARREN-CARBON-MONROE-BERKS-LEHIGH-NORTHAMPTON-
INCLUDING THE CITIES OF...NEWTON...WASHINGTON...JIM THORPE...
STROUDSBURG...READING...ALLENTOWN...BETHLEHEM...EASTON
339 AM EDT FRI AUG 21 2015

...FLASH FLOOD WATCH IS CANCELLED...

THE FLASH FLOOD WATCH FOR PORTIONS OF NORTHERN NEW JERSEY AND
PENNSYLVANIA HAS BEEN CANCELLED. THE HEAVY RAIN THREAT HAS SHIFTED
EAST OF THE WATCH AREA.

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 20, 5:31 PM EDTAreal Flood AdvisoryPHIBerks6 hr
Aug 20, 5:43 PM EDTSpecial Weather StatementPHIBerks47 min
Aug 20, 7:14 PM EDTAreal Flood AdvisoryPHIChester4 hr
Aug 20, 1:53 PM EDTSpecial Weather StatementPHICaroline37 min
Aug 20, 3:26 PM EDTSpecial Weather StatementPHICecil49 min
Aug 20, 2:29 PM EDTSpecial Weather StatementPHIKent, Sussex46 min

Nearby

Flash Flood Watches in New Jersey, 2015Flash Flood Watches in Pennsylvania, 2015Flash Flood Watches in Maryland, 2015Every flash flood watch 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.