Alert archive / New Jersey / Flash Flood Watches in 2018

Flash Flood Watch 14, NWS Philadelphia/Mount Holly

August 18, 20184 states

NWS Philadelphia/Mount Holly issued this flash flood watch at Aug 18, 2018, 3:16 AM EDT for 4 states. It took effect at Aug 18, 2018, 2:00 PM EDT. It was in force for 9 hr.

The area

The counties it named.

The facts

Issued
Aug 18, 2018, 3:16 AM EDT (07:16 UTC)
In effect from
Aug 18, 2018, 2:00 PM EDT
Expired
Aug 18, 2018, 11:29 PM EDT
In force
9 hr
Issued by
NWS Philadelphia/Mount Holly
Flood severity
None
All 25 counties

New Castle County, DE, Cecil County, MD, Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Ocean 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), 70 km from the middle of the area, began a volume at 07:17 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, 7.3 hours before the alert went out and 200 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 2018-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 802 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 2018-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 59 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
802 J/kg
Mixed-layer CIN
-65 J/kg
Mixed-layer LCL
900 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
59 m²/s²
0-3 km storm-relative helicity
119 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

232 
WGUS61 KPHI 180716
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Mount Holly NJ
316 AM EDT Sat Aug 18 2018

DEZ001-MDZ008-NJZ001-007>010-012>020-026-027-PAZ054-055-060>062-
070-071-101>106-190015-
/O.NEW.KPHI.FF.A.0014.180818T1800Z-180819T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Cecil-Sussex-Warren-Morris-Hunterdon-Somerset-
Middlesex-Western Monmouth-Eastern Monmouth-Mercer-Salem-
Gloucester-Camden-Northwestern Burlington-Ocean-Coastal Ocean-
Southeastern Burlington-Carbon-Monroe-Berks-Lehigh-Northampton-
Delaware-Philadelphia-Western Chester-Eastern Chester-
Western Montgomery-Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Wilmington, Elkton, Newton, Washington, 
Morristown, Flemington, Somerville, New Brunswick, Freehold, 
Sandy Hook, Trenton, Pennsville, Glassboro, Camden, Cherry Hill, 
Moorestown, Mount Holly, Jackson, Long Beach Island, 
Wharton State Forest, Jim Thorpe, Stroudsburg, Reading, 
Allentown, Bethlehem, Easton, Media, Philadelphia, Honey Brook, 
Oxford, West Chester, Kennett Square, Collegeville, Pottstown, 
Norristown, Lansdale, Chalfont, Perkasie, Morrisville, 
and Doylestown
316 AM EDT Sat Aug 18 2018

...FLASH FLOOD WATCH IN EFFECT FROM 2 PM EDT THIS AFTERNOON
THROUGH THIS EVENING...

The National Weather Service in Mount Holly has issued a

* Flash Flood Watch for portions of northern Delaware, northeast 
  Maryland, New Jersey, and Pennsylvania, including the 
  following areas, in northern Delaware, New Castle. In 
  northeast Maryland, Cecil. In New Jersey, Camden, Coastal 
  Ocean, Eastern Monmouth, Gloucester, Hunterdon, Mercer, 
  Middlesex, Morris, Northwestern Burlington, Ocean, Salem, 
  Somerset, Southeastern Burlington, Sussex, Warren, and Western 
  Monmouth. In Pennsylvania, Berks, Carbon, Delaware, Eastern 
  Chester, Eastern Montgomery, Lehigh, Lower Bucks, Monroe, 
  Northampton, Philadelphia, Upper Bucks, Western Chester, and 
  Western Montgomery. 

* From 2 PM EDT this afternoon through this evening

* Several rounds of heavy showers and thunderstorms will affect 
  the area through this evening. The heaviest rainfall is expected
  later this afternoon into this evening as a cold front moves 
  across the area. Those areas that received heavy rainfall on 
  Friday will be the most susceptible to flash flooding.

* Heavy rainfall within a short period of time can lead to 
  rapidly rising water and flash flooding, particularly in urban 
  areas, and along small creeks and streams. The ground remains 
  fairly saturated due to recent heavy rains over the past several
  weeks. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flash Flood Watch means that there is the potential for flash
flooding which can be life-threatening. Heavy rain is expected to
occur over a short period of time. Rapidly rising flood waters
may quickly inundate roadways and areas of poor drainage. Streams
and creeks could leave their banks, flooding nearby properties.

Please monitor the forecast, especially if you live in a location
that is prone to flooding. Be prepared to take action if a flash 
flood warning is issued for your area.

&&

$$
3 follow-up statements
643 
WGUS61 KPHI 181939
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
339 PM EDT Sat Aug 18 2018

DEZ001-MDZ008-NJZ001-007>010-012>020-026-027-PAZ054-055-060>062-
070-071-101>106-190400-
/O.CON.KPHI.FF.A.0014.000000T0000Z-180819T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Cecil-Sussex-Warren-Morris-Hunterdon-Somerset-
Middlesex-Western Monmouth-Eastern Monmouth-Mercer-Salem-
Gloucester-Camden-Northwestern Burlington-Ocean-Coastal Ocean-
Southeastern Burlington-Carbon-Monroe-Berks-Lehigh-Northampton-
Delaware-Philadelphia-Western Chester-Eastern Chester-
Western Montgomery-Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Wilmington, Elkton, Newton, Washington, 
Morristown, Flemington, Somerville, New Brunswick, Freehold, 
Sandy Hook, Trenton, Pennsville, Glassboro, Camden, Cherry Hill, 
Moorestown, Mount Holly, Jackson, Long Beach Island, 
Wharton State Forest, Jim Thorpe, Stroudsburg, Reading, 
Allentown, Bethlehem, Easton, Media, Philadelphia, Honey Brook, 
Oxford, West Chester, Kennett Square, Collegeville, Pottstown, 
Norristown, Lansdale, Chalfont, Perkasie, Morrisville, 
and Doylestown
339 PM EDT Sat Aug 18 2018

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL MIDNIGHT EDT
TONIGHT...

The Flash Flood Watch continues for

* Portions of northern Delaware, northeast Maryland, New Jersey, 
  and Pennsylvania, including the following areas, in northern 
  Delaware, New Castle. In northeast Maryland, Cecil. In New 
  Jersey, Camden, Coastal Ocean, Eastern Monmouth, Gloucester, 
  Hunterdon, Mercer, Middlesex, Morris, Northwestern Burlington, 
  Ocean, Salem, Somerset, Southeastern Burlington, Sussex, 
  Warren, and Western Monmouth. In Pennsylvania, Berks, Carbon, 
  Delaware, Eastern Chester, Eastern Montgomery, Lehigh, Lower 
  Bucks, Monroe, Northampton, Philadelphia, Upper Bucks, Western 
  Chester, and Western Montgomery. 

* Until midnight EDT tonight

* Several rounds of heavy showers and thunderstorms will affect 
  the area through this evening. The heaviest rainfall is 
  expected later this afternoon into this evening as a cold 
  front moves across the area. Those areas that received heavy 
  rainfall on Friday will be the most susceptible to flash 
  flooding. 

* Heavy rainfall within a short period of time can lead to 
  rapidly rising water and flash flooding, particularly in urban 
  areas, and along small creeks and streams. The ground remains 
  fairly saturated due to recent heavy rains over the past 
  several weeks. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flash Flood Watch means that there is the potential for flash
flooding which can be life-threatening. Heavy rain is expected to
occur over a short period of time. Rapidly rising flood waters
may quickly inundate roadways and areas of poor drainage. Streams
and creeks could leave their banks, flooding nearby properties.

Please monitor the forecast, especially if you live in a location
that is prone to flooding. Be prepared to take action if a flash
flood warning is issued for your area.

&&

$$
135 
WGUS61 KPHI 190047
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
847 PM EDT Sat Aug 18 2018

DEZ001-MDZ008-NJZ001-007>010-012>015-PAZ054-055-060>062-070-071-
101>106-190200-
/O.CAN.KPHI.FF.A.0014.000000T0000Z-180819T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Cecil-Sussex-Warren-Morris-Hunterdon-Somerset-
Middlesex-Western Monmouth-Eastern Monmouth-Mercer-Carbon-Monroe-
Berks-Lehigh-Northampton-Delaware-Philadelphia-Western Chester-
Eastern Chester-Western Montgomery-Eastern Montgomery-Upper Bucks-
Lower Bucks-
Including the cities of Wilmington, Elkton, Newton, Washington, 
Morristown, Flemington, Somerville, New Brunswick, Freehold, 
Sandy Hook, Trenton, Jim Thorpe, Stroudsburg, Reading, Allentown,
Bethlehem, Easton, Media, Philadelphia, Honey Brook, Oxford, 
West Chester, Kennett Square, Collegeville, Pottstown, 
Norristown, Lansdale, Chalfont, Perkasie, Morrisville, 
and Doylestown
847 PM EDT Sat Aug 18 2018

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for portions of northern Delaware,
northeast Maryland, New Jersey, and Pennsylvania has been
cancelled. A front has crossed much of the area and flash flooding
is no longer expected. 

$$

NJZ016>020-026-027-190400-
/O.CON.KPHI.FF.A.0014.000000T0000Z-180819T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Salem-Gloucester-Camden-Northwestern Burlington-Ocean-
Coastal Ocean-Southeastern Burlington-
Including the cities of Pennsville, Glassboro, Camden, 
Cherry Hill, Moorestown, Mount Holly, Jackson, Long Beach Island,
and Wharton State Forest
847 PM EDT Sat Aug 18 2018

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL MIDNIGHT EDT
TONIGHT...

The Flash Flood Watch continues for

* A portion of southern New Jersey, including the following
  counties, Burlington, Ocean, Camden, Gloucester and Salem.  

* Until midnight EDT tonight

* A few rounds of heavy showers and thunderstorms will affect the
  area through this evening as a front crosses the region. Those 
  areas that received heavy rainfall on Friday will be the most 
  susceptible to flash flooding. 

* Heavy rainfall within a short period of time can lead to 
  rapidly rising water and flash flooding, particularly in urban 
  areas, and along small creeks and streams. The ground remains 
  fairly saturated due to recent heavy rains over the past 
  several weeks. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flash Flood Watch means that there is the potential for flash
flooding which can be life-threatening. Heavy rain is expected to
occur over a short period of time. Rapidly rising flood waters
may quickly inundate roadways and areas of poor drainage. Streams
and creeks could leave their banks, flooding nearby properties.

Please monitor the forecast, especially if you live in a location
that is prone to flooding. Be prepared to take action if a flash
flood warning is issued for your area.

&&

$$
728 
WGUS61 KPHI 190329
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
1129 PM EDT Sat Aug 18 2018

NJZ016>020-026-027-190430-
/O.CAN.KPHI.FF.A.0014.000000T0000Z-180819T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Salem-Gloucester-Camden-Northwestern Burlington-Ocean-
Coastal Ocean-Southeastern Burlington-
Including the cities of Pennsville, Glassboro, Camden, 
Cherry Hill, Moorestown, Mount Holly, Jackson, Long Beach Island,
and Wharton State Forest
1129 PM EDT Sat Aug 18 2018

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for a portion of southern New Jersey has
been cancelled. 

The heavy rain threat has diminished and the flash flooding threat
has decreased as well. Therefore the Flash Flood Watch has been
cancelled. However, there will still be scattered showers or 
thunderstorms for some areas overnight.

$$

Robertson

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 17, 8:04 PM EDTSpecial Weather StatementPHIMonroe41 min
Aug 17, 8:17 PM EDTSevere Thunderstorm WarningPHIBucks43 min
Aug 17, 8:54 PM EDTSpecial Weather StatementPHICarbon, Monroe36 min
Aug 17, 10:59 PM EDTAreal Flood AdvisoryPHIBucks75 min
Aug 18, 12:56 AM EDTAreal Flood AdvisoryPHIChester, Delaware4 hr
Aug 18, 3:20 PM EDTSpecial Weather StatementPHIChester40 min
Aug 18, 4:33 PM EDTSpecial Weather StatementPHIDelaware42 min
Aug 18, 4:54 PM EDTSpecial Weather StatementPHIPhiladelphia21 min
Aug 17, 8:47 PM EDTSevere Thunderstorm WarningPHIHunterdon, Mercer, Middlesex, Morris, Somerset, Sussex43 min
Aug 17, 8:48 PM EDTSpecial Weather StatementPHISussex27 min
Aug 17, 9:26 PM EDTSpecial Weather StatementPHIMercer, Middlesex, Somerset34 min
Aug 17, 11:25 PM EDTSpecial Weather StatementPHISomerset35 min
Aug 17, 11:30 PM EDTFlash Flood WarningPHIHunterdon, Middlesex, Morris, Somerset4 hr
Aug 17, 11:41 PM EDTSevere Thunderstorm WarningPHIMiddlesex, Morris, Somerset34 min
Aug 17, 11:52 PM EDTSpecial Weather StatementPHIMiddlesex23 min
Aug 18, 2:37 AM EDTSpecial Weather StatementPHIOcean23 min
Aug 18, 2:38 AM EDTSpecial Marine WarningPHI52 min
Aug 18, 2:41 AM EDTSpecial Weather StatementPHIAtlantic, Cumberland34 min
Aug 18, 2:46 AM EDTSevere Thunderstorm WarningPHIOcean14 min
Aug 18, 3:15 AM EDTSpecial Marine WarningPHI30 min
Aug 18, 3:34 PM EDTSpecial Weather StatementPHISussex41 min
Aug 18, 3:40 PM EDTSmall Craft AdvisoryPHI45 hr
Aug 18, 4:14 PM EDTSpecial Weather StatementPHISussex46 min
Aug 18, 5:16 PM EDTSpecial Weather StatementPHIBurlington, Camden44 min
Aug 18, 5:44 PM EDTAreal Flood AdvisoryPHIBurlington, Camden98 min
Aug 18, 5:55 PM EDTSpecial Weather StatementPHIBurlington35 min
Aug 18, 6:17 PM EDTSevere Thunderstorm WarningPHIBurlington, Ocean43 min
Aug 18, 6:31 PM EDTSpecial Marine WarningPHI119 min
Aug 18, 6:44 PM EDTSevere Thunderstorm WarningPHIOcean29 min

Nearby

Flash Flood Watches in New Jersey, 2018Flash Flood Watches in Pennsylvania, 2018Flash Flood Watches in Delaware, 2018Every flash flood watch in 2018

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.