Alert archive / New Jersey / Flash Flood Watches in 2020

Flash Flood Watch 8, NWS Philadelphia/Mount Holly

August 13, 20204 states

NWS Philadelphia/Mount Holly issued this flash flood watch at Aug 13, 2020, 3:02 AM EDT for 4 states. It took effect at Aug 13, 2020, 8:00 AM EDT. It was in force for 12 hr.

The area

The counties it named.

The facts

Issued
Aug 13, 2020, 3:02 AM EDT (07:02 UTC)
In effect from
Aug 13, 2020, 8:00 AM EDT
Expired
Aug 13, 2020, 8:19 PM EDT
In force
12 hr
Issued by
NWS Philadelphia/Mount Holly
Flood severity
None
All 26 counties

Kent County, DE, New Castle County, DE, Sussex County, DE, Caroline County, MD, Cecil County, MD, Kent County, MD, Queen Anne's County, MD, Talbot County, MD, Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Cape May County, NJ, Cumberland County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Ocean County, NJ, Salem County, NJ, Somerset County, NJ, Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 73 km from the middle of the area, began a volume at 07:03 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

Wallops Is Stn, VA (KWAL), launched 00:00Z, 7.0 hours before the alert went out and 197 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, Wallops Is Stn, VA at 00:00Z on 2020-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 748 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, Wallops Is Stn, VA at 00:00Z on 2020-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 15 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
748 J/kg
Mixed-layer CIN
-42 J/kg
Mixed-layer LCL
961 m above ground
0-6 km bulk shear
4 kt
0-1 km storm-relative helicity
15 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.

136 
WGUS61 KPHI 130702
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Mount Holly NJ
302 AM EDT Thu Aug 13 2020

DEZ001>004-MDZ008-012-015-019-020-NJZ016>027-PAZ070-071-101-102-
104-106-132100-
/O.NEW.KPHI.FF.A.0008.200813T1200Z-200814T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Kent-Inland Sussex-Delaware Beaches-Cecil-Kent MD-
Queen Annes-Talbot-Caroline-Salem-Gloucester-Camden-
Northwestern Burlington-Ocean-Cumberland-Atlantic-Cape May-
Atlantic Coastal Cape May-Coastal Atlantic-Coastal Ocean-
Southeastern Burlington-Delaware-Philadelphia-Western Chester-
Eastern Chester-Eastern Montgomery-Lower Bucks-
Including the cities of Wilmington, Dover, Georgetown, 
Rehoboth Beach, Elkton, Chestertown, Centreville, Easton, Denton,
Pennsville, Glassboro, Camden, Cherry Hill, Moorestown, 
Mount Holly, Jackson, Millville, Hammonton, Cape May Court House,
Ocean City, Atlantic City, Long Beach Island, 
Wharton State Forest, Media, Philadelphia, Honey Brook, Oxford, 
West Chester, Kennett Square, Norristown, Lansdale, Morrisville, 
and Doylestown
302 AM EDT Thu Aug 13 2020

...FLASH FLOOD WATCH IN EFFECT FROM 8 AM EDT THIS MORNING THROUGH
THIS EVENING...

The National Weather Service in Mount Holly has issued a

* Flash Flood Watch for portions of Delaware, northeastern 
  Maryland, southern New Jersey and southeastern Pennsylvania.

* From 8:00 AM this morning until midnight tonight.

* Slow moving showers and thunderstorms are expected to develop 
  in the region today. Locally heavy downpours are anticipated. 
  Rainfall amounts as high as 2 to 4 inches are possible in a 
  short amount of time.

* The ground remains saturated and streams and creeks are running
  high. As a result, much of the area is more susceptible to
  flooding than usual. The heavy rain will result in flooding of
  roadways and areas of poor drainage, as well as small streams
  and creeks.

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.

&&

$$

Iovino
3 follow-up statements
047 
WGUS61 KPHI 131154
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Mount Holly NJ
754 AM EDT Thu Aug 13 2020

NJZ009-010-012>015-PAZ103-105-140000-
/O.EXA.KPHI.FF.A.0008.200813T1200Z-200814T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon-Somerset-Middlesex-Western Monmouth-Eastern Monmouth-
Mercer-Western Montgomery-Upper Bucks-
Including the cities of Flemington, Somerville, New Brunswick, 
Freehold, Sandy Hook, Trenton, Collegeville, Pottstown, Chalfont,
and Perkasie
754 AM EDT Thu Aug 13 2020

...FLASH FLOOD WATCH IN EFFECT THROUGH THIS EVENING...

The National Weather Service in Mount Holly has expanded the

* Flash Flood Watch to include portions of New Jersey and 
  southeast Pennsylvania, including the following areas, in New 
  Jersey, Eastern Monmouth, Hunterdon, Mercer, Middlesex, 
  Somerset, and Western Monmouth. In southeast Pennsylvania, 
  Upper Bucks and Western Montgomery. 

* Through this evening

* Slow moving showers and thunderstorms are expected in the 
  region today. Locally heavy downpours are anticipated. Rainfall 
  amounts as high as 2 to 4 inches are possible in a short amount 
  of time. 

* The ground remains saturated and streams and creeks are 
  running high. As a result, much of the area is more 
  susceptible to flooding than usual. The heavy rain will result 
  in flooding of roadways and areas of poor drainage, as well as 
  small streams and creeks. 

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.

&&

$$

DEZ001>004-MDZ008-012-015-019-020-NJZ016>027-PAZ070-071-101-102-
104-106-140000-
/O.CON.KPHI.FF.A.0008.200813T1200Z-200814T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Kent-Inland Sussex-Delaware Beaches-Cecil-Kent MD-
Queen Annes-Talbot-Caroline-Salem-Gloucester-Camden-
Northwestern Burlington-Ocean-Cumberland-Atlantic-Cape May-
Atlantic Coastal Cape May-Coastal Atlantic-Coastal Ocean-
Southeastern Burlington-Delaware-Philadelphia-Western Chester-
Eastern Chester-Eastern Montgomery-Lower Bucks-
Including the cities of Wilmington, Dover, Georgetown, 
Rehoboth Beach, Elkton, Chestertown, Centreville, Easton, Denton,
Pennsville, Glassboro, Camden, Cherry Hill, Moorestown, 
Mount Holly, Jackson, Millville, Hammonton, Cape May Court House,
Ocean City, Atlantic City, Long Beach Island, 
Wharton State Forest, Media, Philadelphia, Honey Brook, Oxford, 
West Chester, Kennett Square, Norristown, Lansdale, Morrisville, 
and Doylestown
754 AM EDT Thu Aug 13 2020

...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH THIS EVENING...

The Flash Flood Watch continues for

* Portions of Delaware, northeast Maryland, southern New Jersey,
  and southeast Pennsylvania. 

* Through this evening

* Slow moving showers and thunderstorms are expected to develop 
  in the region today. Locally heavy downpours are anticipated. 
  Rainfall amounts as high as 2 to 4 inches are possible in a 
  short amount of time. 

* The ground remains saturated and streams and creeks are 
  running high. As a result, much of the area is more 
  susceptible to flooding than usual. The heavy rain will result 
  in flooding of roadways and areas of poor drainage, as well as 
  small streams and creeks. 

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.

&&

$$

CMS
536 
WGUS61 KPHI 132124
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
524 PM EDT Thu Aug 13 2020

DEZ001>004-MDZ008-012-015-019-020-NJZ009-010-012>027-PAZ070-071-
101>106-140400-
/O.CON.KPHI.FF.A.0008.000000T0000Z-200814T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Kent-Inland Sussex-Delaware Beaches-Cecil-Kent MD-
Queen Annes-Talbot-Caroline-Hunterdon-Somerset-Middlesex-
Western Monmouth-Eastern Monmouth-Mercer-Salem-Gloucester-Camden-
Northwestern Burlington-Ocean-Cumberland-Atlantic-Cape May-
Atlantic Coastal Cape May-Coastal Atlantic-Coastal Ocean-
Southeastern Burlington-Delaware-Philadelphia-Western Chester-
Eastern Chester-Western Montgomery-Eastern Montgomery-Upper Bucks-
Lower Bucks-
Including the cities of Wilmington, Dover, Georgetown, 
Rehoboth Beach, Elkton, Chestertown, Centreville, Easton, Denton,
Flemington, Somerville, New Brunswick, Freehold, Sandy Hook, 
Trenton, Pennsville, Glassboro, Camden, Cherry Hill, Moorestown, 
Mount Holly, Jackson, Millville, Hammonton, Cape May Court House,
Ocean City, Atlantic City, Long Beach Island, 
Wharton State Forest, Media, Philadelphia, Honey Brook, Oxford, 
West Chester, Kennett Square, Collegeville, Pottstown, 
Norristown, Lansdale, Chalfont, Perkasie, Morrisville, 
and Doylestown
524 PM EDT Thu Aug 13 2020

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

The Flash Flood Watch continues for

* Portions of Delaware, northeast Maryland, New Jersey, and 
  southeast Pennsylvania, including the following areas, in 
  Delaware, Delaware Beaches, Inland Sussex, Kent, and New 
  Castle. In northeast Maryland, Caroline, Cecil, Kent MD, Queen 
  Annes, and Talbot. In New Jersey, Atlantic, Atlantic Coastal 
  Cape May, Camden, Cape May, Coastal Atlantic, Coastal Ocean, 
  Cumberland, Eastern Monmouth, Gloucester, Hunterdon, Mercer, 
  Middlesex, Northwestern Burlington, Ocean, Salem, Somerset, 
  Southeastern Burlington, and Western Monmouth. In southeast 
  Pennsylvania, Delaware, Eastern Chester, Eastern Montgomery, 
  Lower Bucks, Philadelphia, Upper Bucks, Western Chester, and 
  Western Montgomery. 

* Until midnight EDT tonight

* Slow moving showers and thunderstorms are expected to continue
  into the evening. Locally heavy downpours are anticipated. 
  Rainfall amounts as high as 2 to 4 inches are possible in a 
  short amount of time. 

* The ground remains saturated and streams and creeks are 
  running high. As a result, much of the area is more 
  susceptible to flooding than usual. The heavy rain will result 
  in flooding of roadways and areas of poor drainage, as well as 
  small streams and creeks. 

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.

&&

$$
596 
WGUS61 KPHI 140019
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
819 PM EDT Thu Aug 13 2020

DEZ001>004-MDZ008-012-015-019-020-NJZ009-010-012>027-PAZ070-071-
101>106-140130-
/O.CAN.KPHI.FF.A.0008.000000T0000Z-200814T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Kent-Inland Sussex-Delaware Beaches-Cecil-Kent MD-
Queen Annes-Talbot-Caroline-Hunterdon-Somerset-Middlesex-
Western Monmouth-Eastern Monmouth-Mercer-Salem-Gloucester-Camden-
Northwestern Burlington-Ocean-Cumberland-Atlantic-Cape May-
Atlantic Coastal Cape May-Coastal Atlantic-Coastal Ocean-
Southeastern Burlington-Delaware-Philadelphia-Western Chester-
Eastern Chester-Western Montgomery-Eastern Montgomery-Upper Bucks-
Lower Bucks-
Including the cities of Wilmington, Dover, Georgetown, 
Rehoboth Beach, Elkton, Chestertown, Centreville, Easton, Denton,
Flemington, Somerville, New Brunswick, Freehold, Sandy Hook, 
Trenton, Pennsville, Glassboro, Camden, Cherry Hill, Moorestown, 
Mount Holly, Jackson, Millville, Hammonton, Cape May Court House,
Ocean City, Atlantic City, Long Beach Island, 
Wharton State Forest, Media, Philadelphia, Honey Brook, Oxford, 
West Chester, Kennett Square, Collegeville, Pottstown, 
Norristown, Lansdale, Chalfont, Perkasie, Morrisville, 
and Doylestown
819 PM EDT Thu Aug 13 2020

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for portions of Delaware, northeast
Maryland, New Jersey, and southeast Pennsylvania has been
cancelled.

Showers and thunderstorms producing heavy rain and flash flooding
have ended. Therefore, the Flash Flood Watch has been cancelled.

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 13, 7:47 AM EDTAreal Flood AdvisoryPHIHunterdon, Mercer, Middlesex, Somerset118 min
Aug 13, 8:37 AM EDTFlash Flood WarningPHIHunterdon, Mercer, Middlesex, Somerset3 hr
Aug 13, 9:36 AM EDTAreal Flood AdvisoryPHIHunterdon, Middlesex, Morris, Somerset114 min
Aug 13, 10:01 AM EDTFlash Flood WarningPHIMiddlesex, Morris, Somerset3 hr
Aug 13, 1:06 PM EDTSpecial Weather StatementPHIOcean39 min
Aug 13, 1:30 PM EDTSpecial Weather StatementPHICumberland45 min
Aug 13, 1:56 PM EDTAreal Flood AdvisoryPHIAtlantic, Cape May, Cumberland2 hr
Aug 13, 1:58 PM EDTAreal Flood AdvisoryPHIAtlantic, Burlington, Ocean2 hr
Aug 13, 2:44 PM EDTAreal Flood AdvisoryPHIAtlantic2 hr
Aug 13, 3:54 PM EDTSpecial Weather StatementPHICape May36 min
Aug 13, 4:01 PM EDTAreal Flood AdvisoryPHICape May2 hr
Aug 13, 4:52 PM EDTFlash Flood WarningPHICape May113 min
Aug 13, 7:25 AM EDTAreal Flood AdvisoryPHIBucks, Montgomery2 hr
Aug 13, 9:07 AM EDTFlash Flood WarningPHIBucks, Montgomery3 hr
Aug 13, 3:30 PM EDTAreal Flood AdvisoryPHIPhiladelphia3 hr
Aug 13, 3:56 PM EDTAreal Flood AdvisoryPHIDelaware2 hr
Aug 13, 4:45 PM EDTAreal Flood AdvisoryPHIChester, Montgomery84 min
Aug 13, 10:14 AM EDTFlash Flood WarningPHIKent, Queen Anne's4 hr
Aug 13, 11:28 AM EDTAreal Flood AdvisoryPHICaroline, Kent, Queen Anne's, Talbot4 hr
Aug 13, 11:46 AM EDTAreal Flood AdvisoryPHICecil, Kent3 hr
Aug 13, 12:02 PM EDTFlash Flood WarningPHIKent, Queen Anne's2 hr
Aug 13, 11:56 AM EDTAreal Flood AdvisoryPHIKent, Sussex3 hr
Aug 13, 12:22 PM EDTSpecial Weather StatementPHISussex38 min

Nearby

Flash Flood Watches in New Jersey, 2020Flash Flood Watches in Pennsylvania, 2020Flash Flood Watches in Maryland, 2020Every flash flood watch in 2020

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.