Alert archive / New Jersey / Flash Flood Warnings in 2026
Flash Flood Warning 132, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 27, 2026, 1:17 PM EDT for Mercer County, Somerset County, New Jersey; Bucks County, Pennsylvania. It was in force for 7 hr. 10 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Aug 27, 2026, 1:17 PM EDT (17:17 UTC)
- Expired
- Aug 27, 2026, 8:09 PM EDT
- In force
- 7 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Mercer County, NJ, Somerset County, NJ, Bucks County, PA
The radar
The Philadelphia radar (KDIX), 53 km from the middle of the area, began a volume at 17:19 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 27, 1:56 PM EDT | FLASH FLOOD | 1 Sw North Princeton, NJ | Several road closures due to flooding reported by local PD including Elm Rd & Mountain Ave, Rollingmead St, Terhune Rd, Randall Rd, Mansgrove Rd, Walnut Ln. State Rd flooded in various spots. Time given in report. |
| Aug 27, 2:40 PM EDT | RAIN 2.2 | 2 Nne Pennington, NJ | |
| Aug 27, 3:30 PM EDT | RAIN 1.78 | 1 Ne North Princeton, NJ | Mesonet station GW3822 PRINCETON. |
| Aug 27, 3:30 PM EDT | RAIN 1.89 | 2 W Princeton, NJ | Mesonet station FW0303 Princeton. |
| Aug 27, 4:15 PM EDT | RAIN 1.89 | 2 W Princeton, NJ | Mesonet station FW0303 Princeton. |
| Aug 27, 4:21 PM EDT | RAIN 1.78 | 1 Ne North Princeton, NJ | Mesonet station GW3822 PRINCETON. |
| Aug 27, 6:15 PM EDT | RAIN 1.81 | 1 Ne North Princeton, NJ | Mesonet station GW3822 PRINCETON. |
| Aug 27, 6:15 PM EDT | RAIN 1.93 | 2 W Princeton, NJ | Mesonet station FW0303 Princeton. |
| Aug 27, 6:19 PM EDT | RAIN 3.17 | 2 Nne Warminster, PA | Mesonet station GW4409 WARMINSTER. |
| Aug 27, 8:03 PM EDT | FLOOD | 1 Sw Wrightstown Twp, PA | The Neshaminy Creek at Penns Park went into flood stage. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Brookhaven, NY (KOKX), launched 12:00Z, 5.3 hours before the alert went out and 174 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.
- Mixed-layer CAPE
- 346 J/kg
- Mixed-layer CIN
- -24 J/kg
- Mixed-layer LCL
- 890 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km storm-relative helicity
- 83 m²/s²
- 0-3 km storm-relative helicity
- 87 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
627
WGUS51 KPHI 271717
FFWPHI
NJC021-035-PAC017-272115-
/O.NEW.KPHI.FF.W.0132.260827T1717Z-260827T2115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
Issued by National Weather Service New York NY
117 PM EDT Thu Aug 27 2026
The National Weather Service in Mount Holly has issued a
* Flash Flood Warning for...
Mercer County in central New Jersey...
Southwestern Somerset County in northern New Jersey...
Southeastern Bucks County in southeastern Pennsylvania...
* Until 515 PM EDT.
* At 117 PM EDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 1 and 2 inches of rain
have fallen. The expected rainfall rate is 1 to 2 inches in 1 hour.
Additional rainfall amounts up to 0.5 inches are possible in the
warned area. Flash flooding is ongoing or expected to begin
shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar indicated.
IMPACT...Flash flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other poor
drainage and low-lying areas.
* Some locations that will experience flash flooding include...
Trenton, Ewing, Princeton, Bristol, Pennington, Yardley, Newtown,
Hopewell, Tullytown and Langhorne.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 4034 7493 4035 7486 4038 7487 4038 7480
4042 7481 4042 7475 4045 7476 4049 7468
4039 7465 4038 7460 4037 7462 4032 7462
4029 7456 4029 7452 4012 7480 4013 7482
4008 7487 4017 7507 4023 7517 4035 7495
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1-2 INCHES IN 1 HOUR
$$
PHI4 follow-up statements
064
WGUS51 KPHI 272113
FFWPHI
NJC021-035-PAC017-272215-
/O.EXT.KPHI.FF.W.0132.000000T0000Z-260827T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
Issued by National Weather Service New York NY
513 PM EDT Thu Aug 27 2026
The National Weather Service in Mount Holly has extended the
* Flash Flood Warning for...
Mercer County in central New Jersey...
Southwestern Somerset County in northern New Jersey...
Southeastern Bucks County in southeastern Pennsylvania...
* Until 615 PM EDT.
* At 513 PM EDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 1 and 2 inches of rain
have fallen. The expected rainfall rate is 1 to 2 inches in 1 hour.
Additional rainfall amounts of 1 to 2 inches are possible in the
warned area. Flash flooding is ongoing or expected to begin shortly
as additional heavy rain is moving into the area leading to an
additional flash flooding threat.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar indicated.
IMPACT...Flash flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other poor
drainage and low-lying areas.
* Some locations that will experience flash flooding include...
Trenton, Ewing, Princeton, Bristol, Pennington, Yardley, Newtown,
Hopewell, Tullytown and Langhorne.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 4034 7493 4035 7486 4038 7487 4038 7480
4042 7481 4042 7475 4045 7476 4049 7468
4039 7465 4038 7460 4037 7462 4032 7462
4029 7456 4029 7452 4012 7480 4013 7482
4008 7487 4017 7507 4023 7517 4035 7495
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1-2 INCHES IN 1 HOUR
$$
PHI166
WGUS51 KPHI 272207
FFWPHI
NJC021-035-PAC017-272315-
/O.EXT.KPHI.FF.W.0132.000000T0000Z-260827T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
Issued by National Weather Service New York NY
607 PM EDT Thu Aug 27 2026
The National Weather Service in Mount Holly has extended the
* Flash Flood Warning for...
Mercer County in central New Jersey...
Southwestern Somerset County in northern New Jersey...
Southeastern Bucks County in southeastern Pennsylvania...
* Until 715 PM EDT.
* At 607 PM EDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 3 and 4 inches of rain
have fallen. The expected rainfall rate is 1 to 2 inches in 1 hour.
Additional rainfall amounts of 1 to 2 inches are possible in the
warned area. Flash flooding is ongoing or expected to begin
shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar indicated.
IMPACT...Flash flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other poor
drainage and low-lying areas.
* Some locations that will experience flash flooding include...
Trenton, Ewing, Princeton, Bristol, Pennington, Yardley, Newtown,
Hopewell, Tullytown and Langhorne.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 4034 7493 4035 7486 4038 7487 4038 7480
4042 7481 4042 7475 4045 7476 4049 7468
4039 7465 4038 7460 4037 7462 4032 7462
4029 7456 4029 7452 4012 7480 4013 7482
4008 7487 4017 7507 4023 7517 4035 7495
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1-2 INCHES IN 1 HOUR
$$
PHI357
WGUS51 KPHI 272308
FFWPHI
NJC021-035-PAC017-280015-
/O.EXT.KPHI.FF.W.0132.000000T0000Z-260828T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
Issued by National Weather Service New York NY
708 PM EDT Thu Aug 27 2026
The National Weather Service in Mount Holly has extended the
* Flash Flood Warning for...
Mercer County in central New Jersey...
Southwestern Somerset County in northern New Jersey...
Southeastern Bucks County in southeastern Pennsylvania...
* Until 815 PM EDT.
* At 708 PM EDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 3 and 4 inches of rain
have fallen. The expected rainfall rate is 1 to 2 inches in 1 hour.
Additional rainfall amounts of 1 to 2 inches are possible in the
warned area. Flash flooding is ongoing or expected to begin
shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar indicated.
IMPACT...Flash flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other poor
drainage and low-lying areas.
* Some locations that will experience flash flooding include...
Trenton, Ewing, Princeton, Bristol, Pennington, Yardley, Newtown,
Hopewell, Tullytown and Langhorne.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 4034 7493 4035 7486 4038 7487 4038 7480
4042 7481 4042 7475 4045 7476 4049 7468
4039 7465 4038 7460 4037 7462 4032 7462
4029 7456 4029 7452 4012 7480 4013 7482
4008 7487 4017 7507 4023 7517 4035 7495
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1-2 INCHES IN 1 HOUR
$$
PHI096
WGUS71 KPHI 280009
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
Issued by National Weather Service New York NY
809 PM EDT Thu Aug 27 2026
NJC021-035-PAC017-280019-
/O.CAN.KPHI.FF.W.0132.000000T0000Z-260828T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Somerset NJ-Bucks PA-
809 PM EDT Thu Aug 27 2026
...FLASH FLOOD WARNING FOR MERCER, SOUTHWESTERN SOMERSET AND
SOUTHEASTERN BUCKS COUNTIES HAS BEEN REPLACED WITH A FLOOD WARNING...
The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures. The Flash
Flood Warning has been replaced by an Areal Flood Warning.
A Flood Watch remains in effect until 400 AM EDT Friday for portions
of northern Delaware, New Jersey, and Pennsylvania.
&&
LAT...LON 4034 7493 4035 7486 4038 7487 4038 7480
4042 7481 4042 7475 4045 7476 4049 7468
4039 7465 4038 7460 4037 7462 4032 7462
4029 7456 4029 7452 4012 7480 4013 7482
4008 7487 4017 7507 4023 7517 4035 7495
$$
PHIThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 27, 11:38 AM EDT | Flash Flood Warning | PHI | Gloucester | 4 hr |
| Aug 27, 12:26 PM EDT | Severe Thunderstorm Warning | PHI | Camden, Gloucester | 49 min |
| Aug 27, 12:41 PM EDT | Flash Flood Warning | PHI | Camden, Gloucester, Salem | 5 hr |
| Aug 27, 1:06 PM EDT | Severe Thunderstorm Warning | PHI | Middlesex | 24 min |
| Aug 27, 1:07 PM EDT | Flash Flood Warning | PHI | Middlesex, Somerset | 4 hr |
| Aug 27, 1:15 PM EDT | Severe Thunderstorm Warning | PHI | Atlantic, Burlington, Camden, Gloucester | 45 min |
| Aug 27, 1:20 PM EDT | Severe Thunderstorm Warning | PHI | Middlesex, Monmouth | 40 min |
| Aug 27, 1:26 PM EDT | Severe Thunderstorm Warning | PHI | Middlesex, Monmouth | 49 min |
| Aug 27, 1:32 PM EDT | Severe Thunderstorm Warning | PHI | Gloucester, Salem | 43 min |
| Aug 27, 1:34 PM EDT | Special Marine Warning | PHI | 21 min | |
| Aug 27, 1:50 PM EDT | Flash Flood Warning | PHI | Salem | 4 hr |
| Aug 27, 1:57 PM EDT | Tornado Warning | PHI | Salem | 11 min |
| Aug 27, 2:02 PM EDT | Severe Thunderstorm Warning | PHI | Monmouth | 28 min |
| Aug 27, 2:13 PM EDT | Severe Thunderstorm Warning | PHI | Monmouth | 47 min |
| Aug 27, 2:16 PM EDT | Severe Thunderstorm Warning | PHI | Camden, Gloucester, Salem | 44 min |
| Aug 27, 2:18 PM EDT | Flash Flood Warning | PHI | Middlesex, Monmouth | 4 hr |
| Aug 27, 2:20 PM EDT | Special Marine Warning | PHI | 40 min | |
| Aug 27, 2:31 PM EDT | Severe Thunderstorm Warning | PHI | Burlington, Ocean | 44 min |
| Aug 27, 2:38 PM EDT | Flash Flood Warning | PHI | Camden | 4 hr |
| Aug 27, 2:58 PM EDT | Severe Thunderstorm Warning | PHI | Monmouth | 30 min |
| Aug 27, 3:00 PM EDT | Special Marine Warning | PHI | 60 min | |
| Aug 27, 3:04 PM EDT | Severe Thunderstorm Warning | PHI | Atlantic, Burlington, Camden | 41 min |
| Aug 27, 3:26 PM EDT | Areal Flood Warning | PHI | Gloucester, Salem | 5 hr |
| Aug 27, 3:43 PM EDT | Flash Flood Warning | PHI | Camden | 3 hr |
| Aug 27, 4:52 PM EDT | Flash Flood Warning | PHI | Warren | 3 hr |
| Aug 27, 4:59 PM EDT | Areal Flood Warning | PHI | Middlesex, Somerset | 4 hr |
| Aug 27, 5:44 PM EDT | Areal Flood Warning | PHI | Camden, Gloucester | 5 hr |
| Aug 27, 6:17 PM EDT | Areal Flood Warning | PHI | Middlesex, Monmouth | 4 hr |
| Aug 27, 7:00 PM EDT | Flash Flood Warning | PHI | Burlington, Camden | 3 hr |
| Aug 27, 7:26 PM EDT | Special Marine Warning | PHI | 32 min | |
| Aug 27, 4:06 PM EDT | Severe Thunderstorm Warning | PHI | Chester | 39 min |
| Aug 27, 5:08 PM EDT | Flash Flood Warning | PHI | Chester, Montgomery | 4 hr |
Nearby
Flash Flood Warnings in New Jersey, 2026Flash Flood Warnings in Pennsylvania, 2026Every flash flood warning 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.