Alert archive / New Jersey / Flash Flood Watches in 2018

Flash Flood Watch 6, NWS Philadelphia/Mount Holly

July 5, 20184 states

NWS Philadelphia/Mount Holly issued this flash flood watch at Jul 5, 2018, 2:59 PM EDT for 4 states. It took effect at Jul 6, 2018, 2:00 AM EDT. It was in force for 9 hr.

The area

The counties it named.

The facts

Issued
Jul 5, 2018, 2:59 PM EDT (18:59 UTC)
In effect from
Jul 6, 2018, 2:00 AM EDT
Expired
Jul 6, 2018, 11:16 AM EDT
In force
9 hr
Issued by
NWS Philadelphia/Mount Holly
Flood severity
None
All 21 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, Salem County, NJ, Somerset County, NJ, Warren County, NJ, Berks County, PA, Bucks County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 67 km from the middle of the area, began a volume at 18:58 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, 7.0 hours before the alert went out and 205 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 2018-07-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 844 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 2018-07-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -4 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
844 J/kg
Mixed-layer CIN
-40 J/kg
Mixed-layer LCL
619 m above ground
0-6 km bulk shear
2 kt
0-1 km storm-relative helicity
-4 m²/s²
0-3 km storm-relative helicity
4 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

937 
WGUS61 KPHI 051859
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Mount Holly NJ
259 PM EDT Thu Jul 5 2018

DEZ001-MDZ008-NJZ007>010-012>019-PAZ060>062-070-071-101>106-
061000-
/O.NEW.KPHI.FF.A.0006.180706T0600Z-180706T1800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Cecil-Warren-Morris-Hunterdon-Somerset-Middlesex-
Western Monmouth-Eastern Monmouth-Mercer-Salem-Gloucester-Camden-
Northwestern Burlington-Berks-Lehigh-Northampton-Delaware-
Philadelphia-Western Chester-Eastern Chester-Western Montgomery-
Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Wilmington, Elkton, Washington, 
Morristown, Flemington, Somerville, New Brunswick, Freehold, 
Sandy Hook, Trenton, Pennsville, Glassboro, Camden, Cherry Hill, 
Moorestown, Mount Holly, Reading, Allentown, Bethlehem, Easton, 
Media, Philadelphia, Honey Brook, Oxford, West Chester, 
Kennett Square, Collegeville, Pottstown, Norristown, Lansdale, 
Chalfont, Perkasie, Morrisville, and Doylestown
259 PM EDT Thu Jul 5 2018

...FLASH FLOOD WATCH IN EFFECT FROM 2 AM EDT FRIDAY THROUGH
FRIDAY AFTERNOON...

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, Eastern 
  Monmouth, Gloucester, Hunterdon, Mercer, Middlesex, Morris, 
  Northwestern Burlington, Salem, Somerset, Warren, and Western 
  Monmouth. In Pennsylvania, Berks, Delaware, Eastern Chester, 
  Eastern Montgomery, Lehigh, Lower Bucks, Northampton, 
  Philadelphia, Upper Bucks, Western Chester, and Western 
  Montgomery. 

* From 2 AM EDT Friday through Friday afternoon

* A period of heavy rain and thunderstorms could result in
  flooding issues early Friday morning through Friday afternoon.
  Generally, 1 to 2 inches of rain is expected, with localized
  amounts of 3 to 4 inches possible. 

* The heaviest rain is expected to fall during the morning hours,
  impacting the morning commute across the area. 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.

&&

$$

Meola
2 follow-up statements
013 
WGUS61 KPHI 060718
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
318 AM EDT Fri Jul 6 2018

DEZ001-MDZ008-NJZ007>010-012>019-PAZ060>062-070-071-101>106-
061800-
/O.CON.KPHI.FF.A.0006.000000T0000Z-180706T1800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Cecil-Warren-Morris-Hunterdon-Somerset-Middlesex-
Western Monmouth-Eastern Monmouth-Mercer-Salem-Gloucester-Camden-
Northwestern Burlington-Berks-Lehigh-Northampton-Delaware-
Philadelphia-Western Chester-Eastern Chester-Western Montgomery-
Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Wilmington, Elkton, Washington, 
Morristown, Flemington, Somerville, New Brunswick, Freehold, 
Sandy Hook, Trenton, Pennsville, Glassboro, Camden, Cherry Hill, 
Moorestown, Mount Holly, Reading, Allentown, Bethlehem, Easton, 
Media, Philadelphia, Honey Brook, Oxford, West Chester, 
Kennett Square, Collegeville, Pottstown, Norristown, Lansdale, 
Chalfont, Perkasie, Morrisville, and Doylestown
318 AM EDT Fri Jul 6 2018

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 2 PM EDT THIS
AFTERNOON...

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, Eastern Monmouth, Gloucester, Hunterdon, 
  Mercer, Middlesex, Morris, Northwestern Burlington, Salem, 
  Somerset, Warren, and Western Monmouth. In Pennsylvania, 
  Berks, Delaware, Eastern Chester, Eastern Montgomery, Lehigh, 
  Lower Bucks, Northampton, Philadelphia, Upper Bucks, Western 
  Chester, and Western Montgomery. 

* Until 2 PM EDT this afternoon

* A period of heavy rain and thunderstorms could result in
  flooding issues through this afternoon. Generally, 1 to 2 
  inches of rain is expected, with localized amounts of 3 to 4 
  inches possible. 

* The heaviest rain is expected to fall during the morning hours,
  impacting the morning commute across the area. 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.

&&

$$
478 
WGUS61 KPHI 061516
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
1116 AM EDT Fri Jul 6 2018

DEZ001-MDZ008-NJZ007>010-012>019-PAZ060>062-070-071-101>106-
061630-
/O.CAN.KPHI.FF.A.0006.000000T0000Z-180706T1800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Cecil-Warren-Morris-Hunterdon-Somerset-Middlesex-
Western Monmouth-Eastern Monmouth-Mercer-Salem-Gloucester-Camden-
Northwestern Burlington-Berks-Lehigh-Northampton-Delaware-
Philadelphia-Western Chester-Eastern Chester-Western Montgomery-
Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Wilmington, Elkton, Washington, 
Morristown, Flemington, Somerville, New Brunswick, Freehold, 
Sandy Hook, Trenton, Pennsville, Glassboro, Camden, Cherry Hill, 
Moorestown, Mount Holly, Reading, Allentown, Bethlehem, Easton, 
Media, Philadelphia, Honey Brook, Oxford, West Chester, 
Kennett Square, Collegeville, Pottstown, Norristown, Lansdale, 
Chalfont, Perkasie, Morrisville, and Doylestown
1116 AM EDT Fri Jul 6 2018

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for portions of northern Delaware, 
northeastern Maryland, New Jersey, and eastern Pennsylvania has 
been cancelled.

Showers and scattered thunderstorms are expected into the early 
afternoon. However, additional rainfall amounts are anticipated to
be less than a half inch. There is no longer a threat of flash 
flooding.

$$

Iovino

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 5, 7:04 PM EDTSpecial Weather StatementPHIMontgomery41 min
Jul 5, 7:08 PM EDTSpecial Weather StatementPHINorthampton37 min
Jul 5, 2:18 PM EDTSpecial Weather StatementPHICaroline, Queen Anne's42 min

Nearby

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