Alert archive / New Jersey / Flood Watches in 2026

Flood Watch 10, NWS Philadelphia/Mount Holly

September 12, 2026New Castle County, Delaware; 11 counties in New Jersey; 4 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this flood watch at Sep 12, 2026, 2:21 AM EDT for New Castle County, Delaware; 11 counties in New Jersey; 4 counties in Pennsylvania. It took effect at Sep 13, 2026, 12:00 AM EDT. It was in force for 12 hr.

The area

The counties it named.

The facts

Issued
Sep 12, 2026, 2:21 AM EDT (06:21 UTC)
In effect from
Sep 13, 2026, 12:00 AM EDT
Expired
Sep 13, 2026, 12:00 PM EDT
In force
12 hr
Issued by
NWS Philadelphia/Mount Holly
Flood severity
None

Counties New Castle County, DE, 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, Bucks County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 46 km from the middle of the area, began a volume at 06:25 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, 6.4 hours before the alert went out and 191 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 2026-09-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCLEL10008507005003002001001 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 2026-09-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 36 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
1245 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
36 m²/s²
0-3 km storm-relative helicity
51 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

721 
WGUS61 KPHI 120621
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Mount Holly NJ
221 AM EDT Sat Sep 12 2026

DEZ001-NJZ008>010-012>020-026-027-PAZ070-071-103>106-122200-
/O.NEW.KPHI.FA.A.0010.260913T0400Z-260913T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Morris-Hunterdon-Somerset-Middlesex-Western Monmouth-
Eastern Monmouth-Mercer-Salem-Gloucester-Camden-Northwestern
Burlington-Ocean-Coastal Ocean-Southeastern Burlington-Delaware-
Philadelphia-Western Montgomery-Eastern Montgomery-Upper Bucks-
Lower Bucks-
Including the cities of Media, Morrisville, Mount Holly, Trenton,
Jackson, Camden, Freehold, Collegeville, Lansdale, Pennsville,
Wharton State Forest, Doylestown, Wilmington, Somerville, New
Brunswick, Cherry Hill, Glassboro, Chalfont, Philadelphia,
Norristown, Morristown, Moorestown, Sandy Hook, Pottstown,
Flemington, Long Beach Island, and Perkasie
221 AM EDT Sat Sep 12 2026

...FLOOD WATCH IN EFFECT FROM LATE TONIGHT THROUGH SUNDAY MORNING...

* WHAT...Flooding caused by excessive rainfall is possible.

* WHERE...Portions of northern Delaware, including the following
  area, New Castle, New Jersey, including the following areas,
  Camden, Coastal Ocean, Eastern Monmouth, Gloucester, Hunterdon,
  Mercer, Middlesex, Morris, Northwestern Burlington, Ocean, Salem,
  Somerset, Southeastern Burlington and Western Monmouth, and
  southeast Pennsylvania, including the following areas, Delaware,
  Eastern Montgomery, Lower Bucks, Philadelphia, Upper Bucks and
  Western Montgomery.

* WHEN...From late tonight through Sunday morning.

* IMPACTS...Excessive runoff may result in flooding of rivers,
  creeks, streams, and other low-lying and flood-prone locations.

* ADDITIONAL DETAILS...
  - Showers and thunderstorms will develop this evening, and then
    will become more widespread late tonight and into Sunday morning.
    Some of these showers and thunderstorms will be capable of heavy
    rainfall, with as much as 1 to 2 inches of rain possible in the
    strongest storms in a short window of time.
  - http://www.weather.gov/safety/flood

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be alert for possible Flood
Warnings. Those living in areas prone to flooding should be prepared
to take action should flooding develop.

&&

$$

MPS
3 follow-up statements
612 
WGUS61 KPHI 121836
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
236 PM EDT Sat Sep 12 2026

DEZ001-NJZ008>010-012>020-026-027-PAZ070-071-103>106-130900-
/O.CON.KPHI.FA.A.0010.260913T0400Z-260913T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Morris-Hunterdon-Somerset-Middlesex-Western Monmouth-
Eastern Monmouth-Mercer-Salem-Gloucester-Camden-Northwestern
Burlington-Ocean-Coastal Ocean-Southeastern Burlington-Delaware-
Philadelphia-Western Montgomery-Eastern Montgomery-Upper Bucks-
Lower Bucks-
Including the cities of Mount Holly, Somerville, Freehold, Pottstown,
Doylestown, Glassboro, Media, Morrisville, Jackson, Philadelphia,
Collegeville, Pennsville, Norristown, Flemington, Perkasie, Chalfont,
Sandy Hook, Camden, Morristown, Wharton State Forest, Lansdale, New
Brunswick, Cherry Hill, Trenton, Long Beach Island, Wilmington, and
Moorestown
236 PM EDT Sat Sep 12 2026

...FLOOD WATCH REMAINS IN EFFECT FROM MIDNIGHT EDT TONIGHT THROUGH
SUNDAY MORNING...

* WHAT...Flooding caused by excessive rainfall continues to be
  possible.

* WHERE...Portions of northern Delaware, including the following
  area, New Castle, New Jersey, including the following areas,
  Camden, Coastal Ocean, Eastern Monmouth, Gloucester, Hunterdon,
  Mercer, Middlesex, Morris, Northwestern Burlington, Ocean, Salem,
  Somerset, Southeastern Burlington and Western Monmouth, and
  southeast Pennsylvania, including the following areas, Delaware,
  Eastern Montgomery, Lower Bucks, Philadelphia, Upper Bucks and
  Western Montgomery.

* WHEN...From midnight EDT tonight through Sunday morning.

* IMPACTS...Excessive runoff may result in flooding of rivers,
  creeks, streams, and other low-lying and flood-prone locations.

* ADDITIONAL DETAILS...
  - Showers and thunderstorms will move into the area around or
    shortly after midnight and continue for several hours before
    tapering off by around mid to late morning Sunday. Some of these
    showers and thunderstorms will be capable of producing heavy
    rainfall, with as much as 1 to 2 inches of rain possible in the
    heaviest storms in a short window of time.
  - http://www.weather.gov/safety/flood

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be alert for possible Flood
Warnings. Those living in areas prone to flooding should be prepared
to take action should flooding develop.

&&

$$

Fitzsimmons
713 
WGUS61 KPHI 130646
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
246 AM EDT Sun Sep 13 2026

DEZ001-NJZ008>010-012>020-026-027-PAZ070-071-103>106-131600-
/O.CON.KPHI.FA.A.0010.000000T0000Z-260913T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Morris-Hunterdon-Somerset-Middlesex-Western Monmouth-
Eastern Monmouth-Mercer-Salem-Gloucester-Camden-Northwestern
Burlington-Ocean-Coastal Ocean-Southeastern Burlington-Delaware-
Philadelphia-Western Montgomery-Eastern Montgomery-Upper Bucks-
Lower Bucks-
Including the cities of Perkasie, Flemington, Mount Holly,
Norristown, Lansdale, Doylestown, Glassboro, Camden, Long Beach
Island, Philadelphia, Moorestown, Jackson, Wilmington, Collegeville,
Media, New Brunswick, Sandy Hook, Trenton, Wharton State Forest,
Chalfont, Somerville, Pennsville, Cherry Hill, Pottstown, Morristown,
Freehold, and Morrisville
246 AM EDT Sun Sep 13 2026

...FLOOD WATCH REMAINS IN EFFECT UNTIL NOON EDT TODAY...

* WHAT...Flooding caused by excessive rainfall continues to be
  possible.

* WHERE...Portions of northern Delaware, including the following
  area, New Castle, New Jersey, including the following areas,
  Camden, Coastal Ocean, Eastern Monmouth, Gloucester, Hunterdon,
  Mercer, Middlesex, Morris, Northwestern Burlington, Ocean, Salem,
  Somerset, Southeastern Burlington and Western Monmouth, and
  southeast Pennsylvania, including the following areas, Delaware,
  Eastern Montgomery, Lower Bucks, Philadelphia, Upper Bucks and
  Western Montgomery.

* WHEN...Until noon EDT today.

* IMPACTS...Excessive runoff may result in flooding of rivers,
  creeks, streams, and other low-lying and flood-prone locations.

* ADDITIONAL DETAILS...
  - Showers and storms will continue to move through the region
    through the morning hours. Heavy rain in a short amount of time
    could result in excessive runoff.
  - http://www.weather.gov/safety/flood

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be alert for possible Flood
Warnings. Those living in areas prone to flooding should be prepared
to take action should flooding develop.

&&

$$
244 
WGUS61 KPHI 131549
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
1149 AM EDT Sun Sep 13 2026

DEZ001-NJZ008>010-012>020-026-027-PAZ070-071-103>106-131700-
/O.EXP.KPHI.FA.A.0010.000000T0000Z-260913T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Morris-Hunterdon-Somerset-Middlesex-Western Monmouth-
Eastern Monmouth-Mercer-Salem-Gloucester-Camden-Northwestern
Burlington-Ocean-Coastal Ocean-Southeastern Burlington-Delaware-
Philadelphia-Western Montgomery-Eastern Montgomery-Upper Bucks-
Lower Bucks-
Including the cities of Glassboro, Cherry Hill, New Brunswick,
Flemington, Chalfont, Norristown, Perkasie, Morrisville, Somerville,
Camden, Jackson, Philadelphia, Mount Holly, Wilmington, Doylestown,
Morristown, Long Beach Island, Lansdale, Moorestown, Freehold,
Trenton, Media, Pottstown, Sandy Hook, Wharton State Forest,
Pennsville, and Collegeville
1149 AM EDT Sun Sep 13 2026

...FLOOD WATCH WILL EXPIRE AT NOON EDT TODAY...

The Flood Watch will expire for portions of northern Delaware,
including the following area, New Castle, New Jersey, including the
following areas, Camden, Coastal Ocean, Eastern Monmouth, Gloucester,
Hunterdon, Mercer, Middlesex, Morris, Northwestern Burlington, Ocean,
Salem, Somerset, Southeastern Burlington and Western Monmouth, and
southeast Pennsylvania, including the following areas, Delaware,
Eastern Montgomery, Lower Bucks, Philadelphia, Upper Bucks and
Western Montgomery.

The flooding threat is ending. Therefore, the Flood Watch will expire
at noon EDT today.

$$

Nearby

Flood Watches in New Jersey, 2026Flood Watches in Pennsylvania, 2026Flood Watches in Delaware, 2026Every flood watch in 2026

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.