Alert archive / New Jersey / Flood Watches in 2026

Flood Watch 8, NWS Philadelphia/Mount Holly

August 19, 2026New Castle County, Delaware; 15 counties in New Jersey; 10 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this flood watch at Aug 19, 2026, 2:08 PM EDT for New Castle County, Delaware; 15 counties in New Jersey; 10 counties in Pennsylvania. It took effect at Aug 20, 2026, 12:00 PM EDT. It was in force for 9 hr.

The area

The counties it named.

The facts

Issued
Aug 19, 2026, 2:08 PM EDT (18:08 UTC)
In effect from
Aug 20, 2026, 12:00 PM EDT
Expired
Aug 20, 2026, 8:45 PM EDT
In force
9 hr
Issued by
NWS Philadelphia/Mount Holly
Flood severity
None
All 26 counties

New Castle County, DE, 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, Sussex County, NJ, Warren County, NJ, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 64 km from the middle of the area, began a volume at 18:09 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, 6.1 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, Brookhaven, NY at 12:00Z on 2026-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 20 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 2026-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -58 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
20 J/kg
Mixed-layer CIN
-61 J/kg
Mixed-layer LCL
1143 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
-58 m²/s²
0-3 km storm-relative helicity
-13 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

332 
WGUS61 KPHI 191808
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Mount Holly NJ
Issued by National Weather Service New York NY
208 PM EDT Wed Aug 19 2026

DEZ001-NJZ009-010-012>022-025>027-PAZ070-071-101>106-200900-
/O.NEW.KPHI.FA.A.0008.260820T1600Z-260821T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Hunterdon-Somerset-Middlesex-Western Monmouth-Eastern
Monmouth-Mercer-Salem-Gloucester-Camden-Northwestern Burlington-
Ocean-Cumberland-Atlantic-Coastal Atlantic-Coastal Ocean-
Southeastern Burlington-Delaware-Philadelphia-Western Chester-
Eastern Chester-Western Montgomery-Eastern Montgomery-Upper Bucks-
Lower Bucks-
Including the cities of Camden, Flemington, Oxford, West Chester,
Pennsville, Trenton, Perkasie, Wilmington, Collegeville, Doylestown,
Lansdale, New Brunswick, Kennett Square, Media, Sandy Hook, Chalfont,
Atlantic City, Pottstown, Philadelphia, Norristown, Morrisville,
Wharton State Forest, Cherry Hill, Hammonton, Honey Brook,
Moorestown, Long Beach Island, Somerville, Mount Holly, Jackson,
Millville, Glassboro, and Freehold
208 PM EDT Wed Aug 19 2026

...FLOOD WATCH IN EFFECT FROM THURSDAY AFTERNOON THROUGH LATE
THURSDAY NIGHT...

* WHAT...Flash flooding caused by excessive rainfall is possible.

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

* WHEN...From Thursday afternoon through late Thursday night.

* IMPACTS...Excessive runoff may result in flooding of rivers,
  creeks, streams, and other low-lying and flood-prone locations.
  Creeks and streams may rise out of their banks. Flooding may occur
  in poor drainage and urban areas.

* ADDITIONAL DETAILS...
  - Multiple rounds of showers and thunderstorms are expected across
    the area beginning Thursday afternoon through Thursday evening.
    Rainfall rates of 1 to 3 inches per hour are possible. Rainfall
    amounts of 1 to 2 inches are possible with localized amounts of 3
    to 5 inches which could cause flash flooding.
  - http://www.weather.gov/safety/flood

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action
should Flash Flood Warnings be issued.

&&

$$

DeSilva
3 follow-up statements
795 
WGUS61 KPHI 200539
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Mount Holly NJ
139 AM EDT Thu Aug 20 2026

NJZ008-202000-
/O.EXA.KPHI.FA.A.0008.260820T1600Z-260821T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Morris-
Including the cities of Morristown
139 AM EDT Thu Aug 20 2026

...FLOOD WATCH IN EFFECT FROM NOON EDT TODAY THROUGH LATE TONIGHT...

* WHAT...Flash flooding caused by excessive rainfall continues to be 
  possible.

* WHERE...A portion of northern New Jersey, including the following 
  county, Morris.

* WHEN...From noon EDT today through late tonight.

* IMPACTS...Flooding may occur in poor drainage and urban areas. 
  Creeks and streams may rise out of their banks. Excessive runoff 
  may result in flooding of rivers, creeks, streams, and other 
  low-lying and flood-prone locations.

* ADDITIONAL DETAILS...
  - Multiple rounds of showers and thunderstorms are expected
    across the area this afternoon through this evening. Rainfall
    rates of 1 to 3 inches per hour are possible. Rainfall
    amounts of 1 to 2 inches are possible with localized amounts
    of 3 to 5 inches which could cause flash flooding.
  - http://www.weather.gov/safety/flood

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

DEZ001-NJZ009-010-012>022-025>027-PAZ070-071-101>106-202000-
/O.CON.KPHI.FA.A.0008.260820T1600Z-260821T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Hunterdon-Somerset-Middlesex-Western Monmouth-Eastern
Monmouth-Mercer-Salem-Gloucester-Camden-Northwestern Burlington-
Ocean-Cumberland-Atlantic-Coastal Atlantic-Coastal Ocean-
Southeastern Burlington-Delaware-Philadelphia-Western Chester-
Eastern Chester-Western Montgomery-Eastern Montgomery-Upper Bucks-
Lower Bucks-
Including the cities of Doylestown, Somerville, Media,
Norristown, Cherry Hill, Philadelphia, Freehold, Perkasie,
Lansdale, Wilmington, Hammonton, Atlantic City, Moorestown,
Jackson, West Chester, Collegeville, Camden, Oxford, Sandy Hook,
Trenton, Honey Brook, Millville, Kennett Square, New Brunswick,
Mount Holly, Long Beach Island, Wharton State Forest,
Morrisville, Flemington, Pennsville, Glassboro, Pottstown, and
Chalfont
139 AM EDT Thu Aug 20 2026

...FLOOD WATCH REMAINS IN EFFECT FROM NOON EDT TODAY THROUGH LATE 
TONIGHT...

* WHAT...Flash 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, 
  Atlantic, Camden, Coastal Atlantic, Coastal Ocean, Cumberland, 
  Eastern Monmouth, Gloucester, Hunterdon, Mercer, Middlesex, 
  Northwestern Burlington, Ocean, Salem, Somerset, Southeastern 
  Burlington and Western Monmouth, and southeast Pennsylvania, 
  including the following areas, Delaware, Eastern Chester, Eastern 
  Montgomery, Lower Bucks, Philadelphia, Upper Bucks, Western 
  Chester and Western Montgomery.

* WHEN...From noon EDT today through late tonight.

* IMPACTS...Flooding may occur in poor drainage and urban areas. 
  Creeks and streams may rise out of their banks. Excessive runoff 
  may result in flooding of rivers, creeks, streams, and other 
  low-lying and flood-prone locations.

* ADDITIONAL DETAILS...
  - Multiple rounds of showers and thunderstorms are expected
    across the area this afternoon through this evening. Rainfall
    rates of 1 to 3 inches per hour are possible. Rainfall
    amounts of 1 to 2 inches are possible with localized amounts
    of 3 to 5 inches which could cause flash flooding.
  - http://www.weather.gov/safety/flood

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

Hoeflich
160 
WGUS61 KPHI 201655
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Mount Holly NJ
1255 PM EDT Thu Aug 20 2026

NJZ001-007-PAZ054-055-060>062-210500-
/O.EXA.KPHI.FA.A.0008.000000T0000Z-260821T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex-Warren-Carbon-Monroe-Berks-Lehigh-Northampton-
Including the cities of Stroudsburg, Newton, Allentown,
Bethlehem, Reading, Washington, Jim Thorpe, and Easton
1255 PM EDT Thu Aug 20 2026

...FLOOD WATCH IN EFFECT THROUGH LATE TONIGHT...

* WHAT...Flash flooding caused by excessive rainfall continues to be 
  possible.

* WHERE...Portions of northern New Jersey, including the following 
  counties, Sussex and Warren and Pennsylvania, including the 
  following counties, Berks, Carbon, Lehigh, Monroe and Northampton.

* WHEN...Through late tonight.

* IMPACTS...Flooding may occur in poor drainage and urban areas. 
  Creeks and streams may rise out of their banks. Excessive runoff 
  may result in flooding of rivers, creeks, streams, and other 
  low-lying and flood-prone locations.

* ADDITIONAL DETAILS...
  - Showers and a thundertorms are expected through this evening.
    Rainfall rates of 1 to 3 inches per hour are possible in
    stronger storms. Total rainfall amounts of 1 to 2 inches are
    expected with some areas experiencing 3 to 5 inches of
    rainfall which could cause flash flooding.
  - http://www.weather.gov/safety/flood

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

DEZ001-NJZ008>010-012>022-025>027-PAZ070-071-101>106-210500-
/O.CON.KPHI.FA.A.0008.000000T0000Z-260821T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Morris-Hunterdon-Somerset-Middlesex-Western Monmouth-
Eastern Monmouth-Mercer-Salem-Gloucester-Camden-Northwestern
Burlington-Ocean-Cumberland-Atlantic-Coastal Atlantic-Coastal
Ocean-Southeastern Burlington-Delaware-Philadelphia-Western
Chester-Eastern Chester-Western Montgomery-Eastern Montgomery-
Upper Bucks-Lower Bucks-
Including the cities of Atlantic City, Wilmington, Wharton State
Forest, Moorestown, Flemington, Collegeville, Media, Kennett
Square, Trenton, Oxford, Glassboro, Pottstown, Chalfont, Sandy
Hook, Freehold, Cherry Hill, Lansdale, Honey Brook, Doylestown,
Hammonton, Camden, New Brunswick, Philadelphia, Norristown,
Jackson, Somerville, Morristown, West Chester, Mount Holly,
Perkasie, Morrisville, Long Beach Island, Pennsville, and
Millville
1255 PM EDT Thu Aug 20 2026

...FLOOD WATCH REMAINS IN EFFECT THROUGH LATE TONIGHT...

* WHAT...Flash 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, 
  Atlantic, Camden, Coastal Atlantic, Coastal Ocean, Cumberland, 
  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 
  Chester, Eastern Montgomery, Lower Bucks, Philadelphia, Upper 
  Bucks, Western Chester and Western Montgomery.

* WHEN...Through late tonight.

* IMPACTS...Flooding may occur in poor drainage and urban areas. 
  Creeks and streams may rise out of their banks. Excessive runoff 
  may result in flooding of rivers, creeks, streams, and other 
  low-lying and flood-prone locations.

* ADDITIONAL DETAILS...
  - Showers and a thundertorms are expected through this evening.
    Rainfall rates of 1 to 3 inches per hour are possible in
    stronger storms. Total rainfall amounts of 1 to 2 inches are
    expected with some areas experiencing 3 to 5 inches of
    rainfall which could cause flash flooding.
  - http://www.weather.gov/safety/flood

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

Manning
553 
WGUS61 KPHI 210045
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
845 PM EDT Thu Aug 20 2026

DEZ001-NJZ001-007>010-012>022-025>027-PAZ054-055-060>062-070-071-
101>106-210145-
/O.CAN.KPHI.FA.A.0008.000000T0000Z-260821T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Sussex-Warren-Morris-Hunterdon-Somerset-Middlesex-
Western Monmouth-Eastern Monmouth-Mercer-Salem-Gloucester-Camden-
Northwestern Burlington-Ocean-Cumberland-Atlantic-Coastal
Atlantic-Coastal Ocean-Southeastern Burlington-Carbon-Monroe-
Berks-Lehigh-Northampton-Delaware-Philadelphia-Western Chester-
Eastern Chester-Western Montgomery-Eastern Montgomery-Upper Bucks-
Lower Bucks-
Including the cities of Morristown, Easton, Perkasie, Wilmington,
Washington, Philadelphia, Allentown, Sandy Hook, Mount Holly, Jim
Thorpe, Atlantic City, Media, Doylestown, Camden, Wharton State
Forest, Bethlehem, Kennett Square, Hammonton, Reading, Long Beach
Island, Pottstown, Morrisville, Chalfont, Millville, Freehold,
Stroudsburg, Flemington, Moorestown, New Brunswick, Pennsville,
Cherry Hill, Norristown, Collegeville, Honey Brook, West Chester,
Somerville, Trenton, Jackson, Lansdale, Newton, Glassboro, and
Oxford
845 PM EDT Thu Aug 20 2026

...FLOOD WATCH IS CANCELLED...

The Flash Flood Watch is cancelled for portions of northern 
Delaware, including the following area, New Castle, New Jersey, 
including the following areas, Atlantic, Camden, Coastal Atlantic, 
Coastal Ocean, Cumberland, Eastern Monmouth, Gloucester, Hunterdon, 
Mercer, Middlesex, Morris, Northwestern Burlington, Ocean, Salem, 
Somerset, Southeastern Burlington, Sussex, Warren and Western 
Monmouth, and Pennsylvania, including the following areas, Berks, 
Carbon, Delaware, Eastern Chester, Eastern Montgomery, Lehigh, Lower 
Bucks, Monroe, Northampton, Philadelphia, Upper Bucks, Western 
Chester and Western Montgomery.

The threat for additional flooding is no longer expected therefore 
the flood watch is cancelled. Please continue to heed any remaining 
road closures.

$$

Manning

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.