Alert archive / New Jersey / Flash Flood Watches in 2020

Flash Flood Watch 9, NWS Philadelphia/Mount Holly

September 9, 20204 states

NWS Philadelphia/Mount Holly issued this flash flood watch at Sep 9, 2020, 5:08 PM EDT for 4 states. It took effect at Sep 10, 2020, 6:00 AM EDT. It was in force for 16 hr.

The area

The counties it named.

The facts

Issued
Sep 9, 2020, 5:08 PM EDT (21:08 UTC)
In effect from
Sep 10, 2020, 6:00 AM EDT
Expired
Sep 10, 2020, 9:45 PM EDT
In force
16 hr
Issued by
NWS Philadelphia/Mount Holly
Flood severity
None
All 30 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, Cumberland 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, 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), 70 km from the middle of the area, began a volume at 21:08 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.1 hours before the alert went out and 214 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, Washington/Dulle, VA at 12:00Z on 2020-09-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Washington/Dulle, VA at 12:00Z on 2020-09-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 2 square meters per square second.193958Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1146 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
2 m²/s²
0-3 km storm-relative helicity
36 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

132 
WGUS61 KPHI 092108
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Mount Holly NJ
508 PM EDT Wed Sep 9 2020



DEZ001-MDZ008-NJZ009-010-012-013-015>019-PAZ070-071-101>106-
100915-
/O.NEW.KPHI.FF.A.0009.200910T1000Z-200911T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Cecil-Hunterdon-Somerset-Middlesex-Western Monmouth-
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, Flemington, 
Somerville, New Brunswick, Freehold, 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, and Doylestown
508 PM EDT Wed Sep 9 2020

...FLASH FLOOD WATCH IN EFFECT FROM THURSDAY MORNING THROUGH
THURSDAY EVENING...

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 areas, in northern Delaware, New Castle. In 
  northeast Maryland, Cecil. In New Jersey, Camden, Gloucester, 
  Hunterdon, Mercer, Middlesex, Northwestern Burlington, Salem, 
  Somerset, and Western Monmouth. In southeast Pennsylvania, 
  Delaware, Eastern Chester, Eastern Montgomery, Lower Bucks, 
  Philadelphia, Upper Bucks, Western Chester, and Western 
  Montgomery. 

* From Thursday morning through Thursday evening

* Heavy showers and thunderstorms are expected for Thursday
  through Thursday evening. A general 1 to 3 inches of rain is
  likely with locally higher amounts possible. 

* Despite the recent dry weather, rain rates may be high enough to
  result in flash flooding. Of particular concern are urban areas
  as well as low lying and poor drainage areas. 


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.

&&

$$

Fitzsimmons
4 follow-up statements
960 
WGUS61 KPHI 100716
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Mount Holly NJ
316 AM EDT Thu Sep 10 2020

DEZ002>004-MDZ012-015-019-020-102000-
/O.EXA.KPHI.FF.A.0009.200910T1000Z-200911T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kent-Inland Sussex-Delaware Beaches-Kent MD-Queen Annes-Talbot-
Caroline-
Including the cities of Dover, Georgetown, Rehoboth Beach, 
Chestertown, Centreville, Easton, and Denton
316 AM EDT Thu Sep 10 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 Delaware and 
  northeast Maryland, including the following areas, in 
  Delaware, Delaware Beaches, Inland Sussex, and Kent. In 
  northeast Maryland, Caroline, Kent MD, Queen Annes, and 
  Talbot. 

* Through this evening

* Heavy showers and thunderstorms will pass through the region 
  today through this evening. Overall, 1 to 3 inches of rain will 
  fall with locally higher amounts possible. 

* Despite the recent dry weather, rain rates may be high enough 
  to result in flash flooding. Of particular concern are urban 
  areas as well as low lying and poor drainage areas. 

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-MDZ008-NJZ009-010-012-013-015>019-PAZ070-071-101>106-
102000-
/O.CON.KPHI.FF.A.0009.200910T1000Z-200911T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Cecil-Hunterdon-Somerset-Middlesex-Western Monmouth-
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, Flemington, 
Somerville, New Brunswick, Freehold, 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, and Doylestown
316 AM EDT Thu Sep 10 2020

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

The Flash Flood Watch continues for

* Portions of northern Delaware, northeast Maryland, New Jersey, 
  and southeast Pennsylvania, including the following areas, in 
  northern Delaware, New Castle. In northeast Maryland, Cecil. 
  In New Jersey, Camden, Gloucester, Hunterdon, Mercer, 
  Middlesex, Northwestern Burlington, Salem, Somerset, and 
  Western Monmouth. In southeast Pennsylvania, Delaware, Eastern 
  Chester, Eastern Montgomery, Lower Bucks, Philadelphia, Upper 
  Bucks, Western Chester, and Western Montgomery. 

* Through this evening

* Heavy showers and thunderstorms will pass through the region 
  today through this evening. Overall, 1 to 3 inches of rain will 
  fall with locally higher amounts possible.

* Despite the recent dry weather, rain rates may be high enough 
  to result in flash flooding. Of particular concern are urban 
  areas as well as low lying and poor drainage areas. 

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.

&&

$$

MPS
996 
WGUS61 KPHI 101903
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Mount Holly NJ
303 PM EDT Thu Sep 10 2020

NJZ007-008-020>022-027-PAZ060>062-110400-
/O.EXA.KPHI.FF.A.0009.000000T0000Z-200911T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Warren-Morris-Ocean-Cumberland-Atlantic-Southeastern Burlington-
Berks-Lehigh-Northampton-
Including the cities of Washington, Morristown, Jackson, 
Millville, Hammonton, Wharton State Forest, Reading, Allentown, 
Bethlehem, and Easton
303 PM EDT Thu Sep 10 2020

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

The National Weather Service in Mount Holly has expanded the

* Flash Flood Watch to include portions of New Jersey and east 
  central Pennsylvania, including the following areas, in New 
  Jersey, Atlantic, Cumberland, Morris, Ocean, Southeastern 
  Burlington, and Warren. In east central Pennsylvania, Berks, 
  Lehigh, and Northampton. 

* Until midnight EDT tonight

* Heavy showers and thunderstorms will pass through the region
  through this evening. Overall, 2 to 3 inches of rain will fall 
  with locally higher amounts possible. 


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-NJZ009-010-012-013-015>019-
PAZ070-071-101>106-110400-
/O.CON.KPHI.FF.A.0009.000000T0000Z-200911T0400Z/
/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-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, Dover, Georgetown, 
Rehoboth Beach, Elkton, Chestertown, Centreville, Easton, Denton,
Flemington, Somerville, New Brunswick, Freehold, 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, 
and Doylestown
303 PM EDT Thu Sep 10 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, Camden, Gloucester, 
  Hunterdon, Mercer, Middlesex, Northwestern Burlington, Salem, 
  Somerset, 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

* Heavy showers and a few thunderstorms will pass through the
  region through this evening. Overall, 2 to 3 inches of rain 
  will fall with locally higher amounts possible. 
 

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 110029
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
829 PM EDT Thu Sep 10 2020



MDZ008-NJZ007>009-PAZ060>062-070-071-101>106-110130-
/O.CAN.KPHI.FF.A.0009.000000T0000Z-200911T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cecil-Warren-Morris-Hunterdon-Berks-Lehigh-Northampton-Delaware-
Philadelphia-Western Chester-Eastern Chester-Western Montgomery-
Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Elkton, Washington, Morristown, 
Flemington, Reading, Allentown, Bethlehem, Easton, Media, 
Philadelphia, Honey Brook, Oxford, West Chester, Kennett Square, 
Collegeville, Pottstown, Norristown, Lansdale, Chalfont, 
Perkasie, Morrisville, and Doylestown
829 PM EDT Thu Sep 10 2020

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for portions of northeast Maryland, New
Jersey, and Pennsylvania has been cancelled. The heaviest rain is
shifting south and east of the region and therefor flash flooding
is not expected. 

$$

DEZ001>004-MDZ012-015-019-020-NJZ010-012-013-015>022-027-110400-
/O.CON.KPHI.FF.A.0009.000000T0000Z-200911T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Kent-Inland Sussex-Delaware Beaches-Kent MD-
Queen Annes-Talbot-Caroline-Somerset-Middlesex-Western Monmouth-
Mercer-Salem-Gloucester-Camden-Northwestern Burlington-Ocean-
Cumberland-Atlantic-Southeastern Burlington-
Including the cities of Wilmington, Dover, Georgetown, 
Rehoboth Beach, Chestertown, Centreville, Easton, Denton, 
Somerville, New Brunswick, Freehold, Trenton, Pennsville, 
Glassboro, Camden, Cherry Hill, Moorestown, Mount Holly, Jackson,
Millville, Hammonton, and Wharton State Forest
829 PM EDT Thu Sep 10 2020

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

The Flash Flood Watch continues for

* Portions of Delaware, northeast Maryland, and New Jersey, 
  including the following areas, in Delaware, Delaware Beaches, 
  Inland Sussex, Kent, and New Castle. In northeast Maryland, 
  Caroline, Kent MD, Queen Annes, and Talbot. In New Jersey, 
  Atlantic, Camden, Cumberland, Gloucester, Mercer, Middlesex, 
  Northwestern Burlington, Ocean, Salem, Somerset, Southeastern 
  Burlington, and Western Monmouth. 

* Until midnight EDT tonight

* Showers with some embedded thunderstorms will continue through
  this evening and some of these could continue to be heavy 
  leading to localized flash flooding. 


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.

&&

$$

Fitzsimmons
323 
WGUS61 KPHI 110145
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
945 PM EDT Thu Sep 10 2020



DEZ001>004-MDZ012-015-019-020-NJZ010-012-013-015>022-027-110245-
/O.CAN.KPHI.FF.A.0009.000000T0000Z-200911T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Kent-Inland Sussex-Delaware Beaches-Kent MD-
Queen Annes-Talbot-Caroline-Somerset-Middlesex-Western Monmouth-
Mercer-Salem-Gloucester-Camden-Northwestern Burlington-Ocean-
Cumberland-Atlantic-Southeastern Burlington-
Including the cities of Wilmington, Dover, Georgetown, 
Rehoboth Beach, Chestertown, Centreville, Easton, Denton, 
Somerville, New Brunswick, Freehold, Trenton, Pennsville, 
Glassboro, Camden, Cherry Hill, Moorestown, Mount Holly, Jackson,
Millville, Hammonton, and Wharton State Forest
945 PM EDT Thu Sep 10 2020

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for portions of Delaware, northeast
Maryland, and New Jersey has been cancelled. Showers are generally
diminishing in intensity and will continue to gradually move out
of the region through tonight. The threat for flash flooding has
therefor ended at this time. 


Fitzsimmons

$$

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.