Areal Flood Warning 18, NWS Philadelphia/Mount Holly

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 PHI

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.

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