Bethlehem, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

789
FXUS61 KPHI 110531
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
131 AM EDT Mon Aug 11 2025

.SYNOPSIS...
High pressure across our area will gradually weaken and shift
east through Tuesday. A surface trough looks to become
established across our area Wednesday into Thursday, then a cold
front settles in from the northwest Thursday into Friday. This
front may then stall nearby or even dissipate into the weekend.

&&

.NEAR TERM /THROUGH TODAY/...
An expansive area of high pressure will be positioned just
offshore through Monday, fostering a light southerly flow and
weak warm air-advection. With the high in control, tranquil
weather is expected. While we will have similar conditions to
last night (clear skies and light winds), temperatures will be a
few degrees warmer overnight, dropping into the upper 50s/low
60s. Areas in and around Philly and at the coast only get into
the mid 60s. Some patchy radiational fog will develop late
tonight/early Monday morning, mainly in South Jersey, southeast
PA (outside of Philadelphia), and Delmarva.

Slightly warmer Monday but still a nice day ahead. Any fog
mixes out not long after daybreak. Mostly sunny skies and
temperatures in the mid to upper 80s, with some spots within the
I-95 corridor touching 90.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
An upper-level ridge across the region Monday night is forecast
to weaken some and shift south through Tuesday. A very warm to
hot air mass will be in place well ahead of a cold front. High
temperatures Tuesday are forecast to be in the upper 80s to low
90s, cooler along the coast and in the higher elevations. Dew
points are forecast to be in the 60s and low 70s Tuesday,
although they may lower some during peak heating. This results
in the heat indices staying safely below the criteria needed for
a Heat Advisory.

As we go through Wednesday, an upper-level trough makes its way
eastward across southeastern Canada to New England and it is
forecast to start glancing our area. A surface trough looks to
be across or near our area, serving as a focus for some low-
level convergence and convective initiation. This may then
spread eastward into the evening before weakening some. The
coverage and intensity of convection is less certain given the
passage of the upper-level trough well to our north. High
temperatures are forecast to be in the upper 80s to low 90s with
dew points into the low 70s for most of the area (although the
dew points may lower some during peak heating). As of now, peak
heat index values are forecast to be right near 100F, especially
for the urban I-95 corridor.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Summary...Warm/hot and humid; lowered chances for showers and
thunderstorms.

Synoptic Overview...An upper-level trough slides across the
Northeast Thursday before lifting out Friday. The flow aloft then
may turn more zonal as an east to west ridge to our south tries to
expand northward some. An upper-level trough however moving across
eastern Canada over the weekend may push the northern part of the
ridge southward. At the surface, a cold front settles in from the
northwest Thursday into Friday. This front may then stall nearby
into the weekend or potentially dissipate by Sunday.

For Thursday...As an upper-level trough slides across the Northeast,
it is forecast to glance our area. A surface trough looks to be
across or near our area ahead of a cold front, however the cold
front itself looks to gradually settle across our area through
Thursday night. The combination of the surface trough and incoming
cold front should serve as a focus for some convective initiation,
however the overall forcing and low-level convergence may be on the
weak side. The coverage and intensity of any convection is less
certain given the dynamics passing well to our north and northeast.
Therefore, PoPs are only 20-30 percent across the area during
Thursday. High temperatures are forecast to be near 90F for many
inland areas. Dew points starting in the lower 70s ahead of the
front should then tend to decrease from the northwest during
the course of the day, although this will depend on the timing
of the actual front. This would result in heat indices peaking
below 100 degrees across the region.

For Friday through Sunday...The flow aloft may become more zonal as
an east to west ridge centered to our south tries to expand
northward some Friday and Saturday. This may also result in the cold
front from Thursday stalling nearby Friday into Saturday before
possibly dissipating. Surface high pressure sliding by to our north
and northeast, if strong enough, would tend to push the weak surface
cold front farther south and bring some drier/less humid air in from
the north. The probabilities for some convection looked to have
decreased, with mainly an isolated chance for some well inland areas
each afternoon. Daytime temperatures are forecast to be on the
toasty side, however given that low enough dew points are forecast,
no extreme heat is anticipated.

&&

.AVIATION /05Z MONDAY THROUGH FRIDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.

Through 12Z...Prevailing VFR for all but KMIV and KACY, where
visibility restrictions in periods of fog are anticipated after
07Z. This could bring conditions down as low as IFR/LIFR
briefly. Also have enough confidence to include brief visibility
restrictions at KILG, but not elsewhere. Light and variable
wind with periods of calm. Moderate confidence in prevailing
VFR, low confidence in timing and extent of restrictions due to
fog.

Monday...VFR. Any fog should quickly dissipate after sunrise.
Light and variable wind in the morning becoming south-
southwesterly in the afternoon around 5 to 10 kt. High
confidence.

Monday night...VFR. Increasing clouds late from southwest to
northeast. Winds diminishing to light and variable after 02-03Z.
High confidence.

Outlook...

Tuesday...Some local low clouds/fog possible Tuesday night,
otherwise VFR.

Wednesday and Thursday...Some showers and thunderstorms possible,
especially Wednesday afternoon and evening, with local sub-VFR
conditions, otherwise VFR.

Friday...VFR overall.

&&

.MARINE...
Sub-SCA conditions on the waters through Monday. Light winds
generally out of the south and seas 2 to 3 feet.

Outlook...

Monday night through Friday...The conditions are anticipated to be
below Small Craft Advisory criteria.

Rip Currents...

For Monday, light southwest wind in the morning will become
south-southeasterly around 10 mph in the afternoon. Breaking
wave heights of 1-3 feet. Easterly swell around 2 feet at 7-9
seconds in length. Monday is also still within two days of the
full moon. Will continue with a MODERATE risk for the
development of dangerous rip currents at all beaches.

For Tuesday, southerly wind increases to around 10-15 mph, with
a 7-9 second period easterly 2 foot swell continuing. As a
result, breaking waves in the surf zone look to remain around
1-3 feet. At this time, will continue to maintain a MODERATE
risk for the development of dangerous rip currents at all
beaches.

For specific beach forecasts, visit weather.gov/beach/phi

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.

&&

$$

SYNOPSIS...Gorse
NEAR TERM...Hoeflich
SHORT TERM...Gorse
LONG TERM...Gorse
AVIATION...Cooper/Gorse/Guzzo/Hoeflich
MARINE...AKL/Cooper/Gorse/Hoeflich