Alert archive / New Jersey / Flash Flood Watches in 2018

Flash Flood Watch 7, NWS Philadelphia/Mount Holly

July 17, 20189 counties in New Jersey; 4 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood watch at Jul 17, 2018, 3:36 AM EDT for 9 counties in New Jersey; 4 counties in Pennsylvania. It took effect at Jul 17, 2018, 11:00 AM EDT. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued
Jul 17, 2018, 3:36 AM EDT (07:36 UTC)
In effect from
Jul 17, 2018, 11:00 AM EDT
Expired
Jul 17, 2018, 6:28 PM EDT
In force
7 hr
Issued by
NWS Philadelphia/Mount Holly
Flood severity
None

Counties Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Somerset County, NJ, Bucks County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 49 km from the middle of the area, began a volume at 07:39 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, 7.6 hours before the alert went out and 183 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 2018-07-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 411 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 2018-07-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -46 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
411 J/kg
Mixed-layer CIN
-120 J/kg
Mixed-layer LCL
1044 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
-46 m²/s²
0-3 km storm-relative helicity
-5 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

685 
WGUS61 KPHI 170736
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Mount Holly NJ
336 AM EDT Tue Jul 17 2018


NJZ008>010-012-013-015-017>019-PAZ070-071-104-106-172000-
/O.NEW.KPHI.FF.A.0007.180717T1500Z-180718T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Morris-Hunterdon-Somerset-Middlesex-Western Monmouth-Mercer-
Gloucester-Camden-Northwestern Burlington-Delaware-Philadelphia-
Eastern Montgomery-Lower Bucks-
Including the cities of Morristown, Flemington, Somerville, 
New Brunswick, Freehold, Trenton, Glassboro, Camden, Cherry Hill,
Moorestown, Mount Holly, Media, Philadelphia, Norristown, 
Lansdale, Morrisville, and Doylestown
336 AM EDT Tue Jul 17 2018

...FLASH FLOOD WATCH IN EFFECT FROM 11 AM EDT THIS MORNING
THROUGH THIS EVENING...

The National Weather Service in Mount Holly has issued a

* Flash Flood Watch for portions of New Jersey and southeast 
  Pennsylvania, including the following areas, in New Jersey, 
  Camden, Gloucester, Hunterdon, Mercer, Middlesex, Morris, 
  Northwestern Burlington, Somerset, and Western Monmouth. In 
  southeast Pennsylvania, Delaware, Eastern Montgomery, Lower 
  Bucks, and Philadelphia. 

* From 11 AM EDT this morning through this evening

* Thunderstorms producing heavy rain could result in flash
  flooding across along and near the Interstate 95 corridor in New
  Jersey and southeastern Pennsylvania. One to two inches of rain
  is expected, though locally higher amounts above 3 inches are
  possible.

* The heaviest rain is expected this afternoon and evening,
  including the afternoon commute. Excessive 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.

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.

&&

$$

SFJ
2 follow-up statements
582 
WGUS61 KPHI 171940
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
340 PM EDT Tue Jul 17 2018

NJZ008>010-012-013-015-017>019-PAZ070-071-104-106-180400-
/O.CON.KPHI.FF.A.0007.000000T0000Z-180718T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Morris-Hunterdon-Somerset-Middlesex-Western Monmouth-Mercer-
Gloucester-Camden-Northwestern Burlington-Delaware-Philadelphia-
Eastern Montgomery-Lower Bucks-
Including the cities of Morristown, Flemington, Somerville, 
New Brunswick, Freehold, Trenton, Glassboro, Camden, Cherry Hill,
Moorestown, Mount Holly, Media, Philadelphia, Norristown, 
Lansdale, Morrisville, and Doylestown
340 PM EDT Tue Jul 17 2018

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

The Flash Flood Watch continues for

* Portions of New Jersey and southeast Pennsylvania, including 
  the following areas, in New Jersey, Camden, Gloucester, 
  Hunterdon, Mercer, Middlesex, Morris, Northwestern Burlington, 
  Somerset, and Western Monmouth. In southeast Pennsylvania, 
  Delaware, Eastern Montgomery, Lower Bucks, and Philadelphia. 

* Until midnight EDT tonight

* Thunderstorms producing heavy rain could result in flash 
  flooding across along and near the Interstate 95 corridor in 
  New Jersey and southeastern Pennsylvania. One to two inches of 
  rain is expected, though locally higher amounts above 3 inches 
  are possible. 

* The heaviest rain is expected through the evening, including 
  the afternoon commute. Excessive 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. 

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.

&&

$$
273 
WGUS61 KPHI 172228
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
628 PM EDT Tue Jul 17 2018

NJZ008>010-012-013-015-017>019-PAZ070-071-104-106-172330-
/O.CAN.KPHI.FF.A.0007.000000T0000Z-180718T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Morris-Hunterdon-Somerset-Middlesex-Western Monmouth-Mercer-
Gloucester-Camden-Northwestern Burlington-Delaware-Philadelphia-
Eastern Montgomery-Lower Bucks-
Including the cities of Morristown, Flemington, Somerville, 
New Brunswick, Freehold, Trenton, Glassboro, Camden, Cherry Hill,
Moorestown, Mount Holly, Media, Philadelphia, Norristown, 
Lansdale, Morrisville, and Doylestown
628 PM EDT Tue Jul 17 2018

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for portions of New Jersey and southeast
Pennsylvania has been cancelled. While a few additional showers
and thunderstorms are possible through the evening hours,
widespread flash flooding is no longer expected.


$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 17, 12:35 PM EDTSpecial Weather StatementPHISussex25 min
Jul 17, 1:31 PM EDTSpecial Weather StatementPHIHunterdon44 min
Jul 17, 1:45 PM EDTSpecial Weather StatementPHIMorris30 min
Jul 17, 2:05 PM EDTAreal Flood AdvisoryPHIHunterdon, Morris, Somerset, Sussex, Warren3 hr
Jul 17, 2:09 PM EDTSpecial Weather StatementPHIMorris36 min
Jul 17, 2:44 PM EDTSpecial Weather StatementPHIMiddlesex31 min
Jul 17, 2:48 PM EDTSpecial Weather StatementPHIMercer27 min
Jul 17, 2:50 PM EDTAreal Flood AdvisoryPHIHunterdon, Mercer, Middlesex, Morris, Somerset3 hr
Jul 17, 2:58 PM EDTSevere Thunderstorm WarningPHIMercer32 min
Jul 17, 3:09 PM EDTSpecial Weather StatementPHIMonmouth36 min
Jul 17, 3:48 PM EDTSpecial Weather StatementPHIOcean57 min
Jul 17, 3:51 PM EDTSpecial Weather StatementPHIMonmouth24 min
Jul 17, 3:54 PM EDTSpecial Marine WarningPHI66 min
Jul 17, 3:58 PM EDTSpecial Weather StatementPHIOcean32 min
Jul 17, 4:00 PM EDTSpecial Weather StatementPHICumberland45 min
Jul 17, 4:03 PM EDTAreal Flood AdvisoryPHIBurlington, Mercer, Middlesex, Monmouth, Ocean2 hr
Jul 17, 4:21 PM EDTSpecial Marine WarningPHI24 min
Jul 17, 4:35 PM EDTFlash Flood WarningPHIOcean4 hr
Jul 17, 4:38 PM EDTSpecial Marine WarningPHI52 min
Jul 17, 4:48 PM EDTSpecial Weather StatementPHICumberland, Ocean57 min
Jul 17, 1:49 PM EDTSpecial Weather StatementPHIChester, Montgomery41 min
Jul 17, 2:21 PM EDTSpecial Weather StatementPHIChester39 min
Jul 17, 2:27 PM EDTFlash Flood WarningPHIBerks, Chester, Montgomery4 hr
Jul 17, 3:35 PM EDTSpecial Weather StatementPHIDelaware, Montgomery25 min

Nearby

Flash Flood Watches in New Jersey, 2018Flash Flood Watches in Pennsylvania, 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.