Alert archive / Pennsylvania / Areal Flood Warnings in 2026
Areal Flood Warning 23, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this areal flood warning at Aug 27, 2026, 9:09 PM EDT for Bucks County, Chester County, Montgomery County, Pennsylvania. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Aug 27, 2026, 9:09 PM EDT (01:09 UTC)
- Expired
- Aug 28, 2026, 12:51 AM EDT
- In force
- 4 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Bucks County, PA, Chester County, PA, Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 88 km from the middle of the area, began a volume at 01:09 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
Washington/Dulle, VA (KIAD), launched 00:00Z, 1.2 hours before the alert went out and 218 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
- 1155 J/kg
- Mixed-layer CIN
- -14 J/kg
- Mixed-layer LCL
- 1287 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 27 m²/s²
- 0-3 km storm-relative helicity
- 65 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 2.3
What forecasters said that day
The local office's own words before this areal flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Philadelphia/Mount Holly wrote its last area forecast discussion before this areal flood warning went out at Aug 27, 3:18 PM EDT, 5 hours 51 minutes earlier. Its key messages:
- 1. The threat of strong to severe thunderstorms and flash flooding will continue through this evening. 2. A cold front is expected to pass through the area on Friday.
Area forecast discussion, Aug 27, 3:18 PM EDT, 5 hours 51 minutes before
Area Forecast Discussion
National Weather Service Mount Holly NJ
318 PM EDT Thu Aug 27 2026
.WHAT HAS CHANGED...
Flood Watch expanded to include the Lehigh Valley and Berks
County.
A Severe Thunderstorm Watch has been issued for all of New
Jersey and portions of Delaware and eastern Pennsylvania
through 8 PM this evening.
The threat for flash flooding is ongoing and will continue
through the afternoon with numerous reports of flooding across
New Jersey and eastern Pennsylvania.
Updated the aviation section for the 06Z TAFs.
&&
.KEY MESSAGES...
1. The threat of strong to severe thunderstorms and flash
flooding will continue through this evening.
2. A cold front is expected to pass through the area on Friday.
&&
.DISCUSSION...
KEY MESSAGE 1...The threat of strong to severe thunderstorms and flash
flooding will continue through this evening.
Widespread showers and thunderstorms continue to impact much of
New Jersey and portions of eastern Pennsylvania and Delaware
this afternoon. The greatest threat from these storms will
continue to be localized flash flooding, with many reports of
road closures due to high water already. Some storms may also be
strong to severe with large hail and damaging winds. A Severe
Thunderstorm Watch remains in effect until 8 PM.
The latest hires guidance suggests that heaviest precipitation
will be generally along the I-95 corridor and points northwest.
Hires guidance has also pointed to areas along the I-78 corridor
potentially seeing heavy rainfall amounts as well. Generally
around 1-2 inches of rain with localized QPF values in excess of
3 inches. Widespread flash flooding still seems unlikely, but
the localized threat remains elevated. The Flood Watch remains
in effect for most of NJ and the I-95 corridor.
For severe hazards, latest CAMS and HREF guidance show SBCAPE
values remaining around 1500-2500 J/kg with ensemble maximums
in excess 3000 J/kg. Deep layer shear forecasts remain around
30kt with a strongly veering profile aloft. Boundary layer flow
is not particularly strong but surface winds are more backed
than previous forecasts so an isolated tornado is possible
primarily along and west of I-95. That said, damaging wind gusts
and hail will remain the greatest threat. Dominant mode should
be multicell convection but a supercell can't be ruled out
especially where cloud bearing shear is maximized. SPC has
expanded the area of a slight risk (2 out of 5) to now include
much of the area.
KEY MESSAGE 2...A cold front is expected to pass through the
area on Friday.
The timing of this cold front will be critical in the risk for
thunderstorm hazards. There are differences between models in
both the timing, and if this will be a single cold front, or an
initial cold front with a reinforcing shot of cold air advection
coming in behind it. Saturday and Sunday appear to be dry across
most of the area with the exception of southern areas Saturday
where low probabilities of showers and storms will exist.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Thursday...Periods of MVFR or lower due to scattered to numerous
showers and thunderstorms. Continue to mention VCTS for the I-95
corridor with PROB30 or TEMPO groups for TSRA. Confidence has
increased that there will be multiple rounds of storms with
frequent lightning and low ceilings, which should begin to
diminish at around 0Z.
Thursday night...VFR as showers and storms exit, but patchy fog
and and low ceilings possible mainly across the I-95 corridor
and RDG/ABE. Winds light and variable. Low confidence.
Outlook...
Friday...Periods of MVFR or lower are possible in showers and
storms.
Saturday through Monday...Prevailing VFR conditions.
&&
.MARINE...
No marine hazards expected. Southerly winds with gusts near 20
kt possible.
Outlook...
Thursday night and through Sunday...No marine hazards expected.
Rip Currents...
There is a MODERATE risk for the development of dangerous and
life threatening rip currents at the Jersey Shore and a LOW risk
at Delaware Beaches.
For Friday, winds in the morning are more westerly at 5 to 10
mph before becoming more southwesterly in the afternoon at 5 to
10 mph. An east-southeasterly swell remains with a period of
6-7 seconds with breaking waves around 2-3 feet. As a result,
there is a MODERATE risk for the development of dangerous and
life threatening rip currents at the Jersey Shore and a LOW risk
at Delaware Beaches.
For specific beach forecasts, visit weather.gov/beach/phi
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Flood Watch through late tonight for PAZ060>062-070-071-
101>106.
NJ...Flood Watch through late tonight for NJZ001-007>010-012>015-
017>020-022-025>027.
DE...Flood Watch through late tonight for DEZ001.
MD...None.
MARINE...None.
&&
DISCUSSION...WFO PHI
AVIATION...WFO PHI
MARINE...WFO PHIHazardous weather outlook, Aug 27, 5:07 AM EDT, 16 hours 2 minutes before
Hazardous Weather Outlook National Weather Service Mount Holly NJ 507 AM EDT Thu Aug 27 2026 MDZ012-015-019-020-280915- Kent MD-Queen Annes-Talbot-Caroline- 507 AM EDT Thu Aug 27 2026 This Hazardous Weather Outlook is for northeast Maryland. .DAY ONE...Today and tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
In the hours before
Local storm report, Aug 27, 5:49 PM EDT, 3 hours 20 minutes before
Preliminary Local Storm Report
National Weather Service Mount Holly NJ
549 PM EDT Thu Aug 27 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0530 PM Flash Flood 1 E North Coventry Twp 40.23N 75.64W
08/27/2026 Chester PA Emergency Mngr
Flooding on 422 near East Coventry Township,
resulting in an accident. Time estimated.
&&
PHILocal storm report, Aug 27, 6:10 PM EDT, 2 hours 59 minutes before
Preliminary Local Storm Report
National Weather Service Mount Holly NJ
610 PM EDT Thu Aug 27 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0545 PM Flash Flood 1 E Atglen 39.95N 75.95W
08/27/2026 Chester PA Trained Spotter
Flooding of Valley Creek at Old Limestone.
Creek is overflowing, resulting in road
closures nearby. Time estimated.
&&
PHILocal storm report, Aug 27, 6:26 PM EDT, 2 hours 43 minutes before
Preliminary Local Storm Report
National Weather Service Mount Holly NJ
626 PM EDT Thu Aug 27 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0441 PM Rain Pitman 39.74N 75.12W
08/27/2026 M5.50 Inch Gloucester NJ Trained Spotter
&&Local storm report, Aug 27, 6:27 PM EDT, 2 hours 42 minutes before
Preliminary Local Storm Report
National Weather Service Mount Holly NJ
627 PM EDT Thu Aug 27 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0620 PM Flash Flood 1 SSE Hatboro 40.16N 75.10W
08/27/2026 Montgomery PA Emergency Mngr
Water rescue reported in Upper Moreland
Township. Time estimated.
&&
PHILocal storm report, Aug 27, 6:29 PM EDT, 2 hours 40 minutes before
Preliminary Local Storm Report
National Weather Service Mount Holly NJ
629 PM EDT Thu Aug 27 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0618 PM Rain Beckett 39.76N 75.36W
08/27/2026 M4.38 Inch Gloucester NJ Mesonet
Mesonet station EW2237 Logan Township.
0615 PM Rain 2 SSW Mullica Hill 39.72N 75.23W
08/27/2026 M4.32 Inch Gloucester NJ Mesonet
Mesonet station CW0566 Mullica Hill.
0615 PM Rain 1 SE Turnersville 39.76N 75.05W
08/27/2026 M3.95 Inch Gloucester NJ Mesonet
Mesonet station EW0923 Turnersville.
0616 PM Rain Quarryville 39.78N 75.49W
08/27/2026 M3.73 Inch New Castle DE Mesonet
Mesonet station EW2337 Bellevue Hills.
0615 PM Rain 1 ENE Sayreville 40.47N 74.34W
08/27/2026 M3.70 Inch Middlesex NJ Mesonet
Mesonet station DW5872 Sayreville.
0616 PM Rain Claymont Heights 39.80N 75.47W
08/27/2026 M3.35 Inch New Castle DE Mesonet
Mesonet station FW2897 CLAYMONT.
0619 PM Rain 2 NNE Warminster 40.23N 75.09W
08/27/2026 M3.17 Inch Bucks PA Mesonet
Mesonet station GW4409 WARMINSTER.
0620 PM Rain 2 S Spotswood 40.37N 74.38W
08/27/2026 M2.86 Inch Middlesex NJ Mesonet
Mesonet station CW1053 Monroe Twp.
0615 PM Rain 2 SSW Browntown 40.38N 74.32W
08/27/2026 M2.71 Inch Middlesex NJ Mesonet
Mesonet station FW8442 Old Bridge.
0515 PM Rain 2 ENE Spotswood 40.41N 74.35W
08/27/2026 M2.50 Inch Middlesex NJ Mesonet
Mesonet station ODBN4 2.3 E Spotswood.
0617 PM Rain 2 SSW Browntown 40.38N 74.32W
08/27/2026 M2.40 Inch Middlesex NJ Mesonet
Mesonet station AV757 Old Bridge.
0615 PM Rain 1 SSW Cedarville 40.21N 75.69W
08/27/2026 M2.33 Inch Chester PA Mesonet
Mesonet station EW5860 Pottstown.
0615 PM Rain 3 E Atco 39.77N 74.84W
08/27/2026 M2.27 Inch Camden NJ Mesonet
Mesonet station FW9968 Atco.
0616 PM Rain 1 E Keansburg 40.44N 74.11W
08/27/2026 M2.12 Inch Monmouth NJ Mesonet
Mesonet station CW1367 N.Middletown.
0620 PM Rain 2 SW Kendall Park 40.42N 74.57W
08/27/2026 M2.12 Inch Middlesex NJ Mesonet
Mesonet station AV400 Kendall Park.
0610 PM Rain 2 NNE Dayton 40.41N 74.49W
08/27/2026 M2.06 Inch Middlesex NJ Mesonet
Mesonet station DEAN4 Deans.
0615 PM Rain 2 WSW Forks Twp 40.72N 75.22W
08/27/2026 M2.03 Inch Northampton PA Mesonet
Mesonet station EW6498 Easton.
0615 PM Rain 2 W Princeton 40.35N 74.69W
08/27/2026 M1.93 Inch Mercer NJ Mesonet
Mesonet station FW0303 Princeton.
0619 PM Rain Worcester Twp 40.20N 75.36W
08/27/2026 M1.90 Inch Montgomery PA Mesonet
Mesonet station CW1648 Worcester.
0615 PM Rain 1 NE North Princeton 40.37N 74.64W
08/27/2026 M1.81 Inch Mercer NJ Mesonet
Mesonet station GW3822 PRINCETON.
0615 PM Rain Pennsville 39.66N 75.52W
08/27/2026 M1.78 Inch Salem NJ Mesonet
Mesonet station FW8127 Pennsville.
0615 PM Rain 1 N High Bridge 40.68N 74.90W
08/27/2026 M1.74 Inch Hunterdon NJ Mesonet
Mesonet station GW3941 GLEN GARDENER.
0620 PM Rain 1 SE New London Twp. 39.78N 75.86W
08/27/2026 M1.72 Inch Chester PA Mesonet
Mesonet station AU860 New London.
&&
MJGLocal storm report, Aug 27, 7:25 PM EDT, 1 hour 44 minutes before
Preliminary Local Storm Report
National Weather Service Mount Holly NJ
725 PM EDT Thu Aug 27 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0648 PM Marine Tstm Wind 4 ESE Woodland Beach 39.32N 75.40W
08/27/2026 M41 MPH ANZ430 DE Buoy
Ship John Shoal measured a 35 kt gust.
&&
PHIThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 27, 8:09 PM EDT | Areal Flood Warning | PHI | Burlington, Hunterdon, Mercer, Middlesex, Somerset | 5 hr |
| Aug 28, 11:12 AM EDT | Special Marine Warning | PHI | 63 min | |
| Aug 28, 12:14 PM EDT | Special Marine Warning | PHI | 61 min | |
| Aug 28, 1:03 PM EDT | Flash Flood Warning | PHI | Atlantic | 4 hr |
| Aug 28, 1:32 PM EDT | Special Marine Warning | PHI | 58 min | |
| Aug 28, 1:48 PM EDT | Flash Flood Warning | PHI | Atlantic, Burlington, Ocean | 4 hr |
| Aug 28, 2:02 PM EDT | Special Marine Warning | PHI | 58 min | |
| Aug 28, 2:08 PM EDT | Severe Thunderstorm Warning | PHI | Atlantic, Burlington, Ocean | 52 min |
| Aug 28, 2:11 PM EDT | Special Marine Warning | PHI | 64 min | |
| Aug 28, 2:44 PM EDT | Severe Thunderstorm Warning | PHI | Ocean | 31 min |
| Aug 28, 2:58 PM EDT | Flash Flood Warning | PHI | Ocean | 3 hr |
| Aug 28, 3:10 PM EDT | Special Marine Warning | PHI | 95 min | |
| Aug 27, 8:16 PM EDT | Flash Flood Warning | PHI | Berks | 4 hr |
| Aug 27, 8:40 PM EDT | Severe Thunderstorm Warning | PHI | Berks | 50 min |
| Aug 27, 9:21 PM EDT | Flash Flood Warning | PHI | Berks | 3 hr |
| Aug 27, 9:32 PM EDT | River Flood Warning | PHI | Bucks | 6 hr |
| Aug 27, 10:22 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Chester | 38 min |
| Aug 27, 10:36 PM EDT | Flash Flood Warning | PHI | Berks, Chester, Montgomery | 3 hr |
| Aug 28, 1:11 PM EDT | Flash Flood Warning | PHI | Sussex | 4 hr |
Nearby
Areal Flood Warnings in Pennsylvania, 2026Every areal 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.