Bethlehem, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

098
FXUS61 KPHI 281429
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
1029 AM EDT Wed May 28 2025

.SYNOPSIS...
Primary low pressure tracks across the Ohio Valley and into the
Great Lakes while weakening today. Secondary low pressure
gradually tracks northward from the Carolinas today then out to
sea late tonight and Thursday. A cold front stalls in the area
Friday, with the next low pressure tracking along it Friday
night. The next cold front crosses our area late Saturday. High
pressure will then arrive for Sunday and generally persist
through Tuesday next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1030 AM, a shield of rain covers much of the region however
lingering drier air to the north and northeast has slowed the
northward progression of the deeper moisture. Temperatures this
morning are the warmest across the far northern zones as a
result given no rain yet and a delay in the thicker cloud cover.
Made some adjustments based on the latest observations and
trends.

Otherwise, an upper-level low centered over the Midwest this
morning will move slowly eastward into the Great Lakes through
today and into tonight. At the surface, broad low pressure
initially centered over portions of the Tennessee and Ohio
Valleys will move northeastward. A new coastal low will begin to
develop later this morning south of the Delmarva and track
generally northeastward into tonight.

Broad ascent ahead of the approaching storm system will continue
to lead to rain spreading northward which should become a bit
heavier through the afternoon especially across the southern to
central areas. It will be a rainy and much cooler day across
the area. As the coastal low deepens into this afternoon, winds
out of the east-southeast will increase to 10-15 mph across
most areas, and some gusts to 20-25 mph especially closer to
the coast.

Rainfall will continue into tonight before beginning to
diminish from southwest to northeast as the double-barrelled
system moves northeast and its influence over the area weakens.
Flash flooding is not expected with this system as the rainfall
will be steady and fall over a long period of time. However,
minor areas of urban flooding are certainly possible. Rainfall
amounts are expected to be in the 0.5-1" range across the
northern half of the area. A general 1-1.5" is expected across
southeastern Pennsylvania including the Philly metro, southern
New Jersey, and the Delmarva. Amounts could approach or exceed
2" in some locales, with this appearing most likely for portions
of Delaware and far southern New Jersey.

A few showers will remain possible through the remainder of the
overnight hours, with plentiful clouds remaining in place as
well. Temperatures will remain nearly steady in the 50s to near
60.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Guidance has trended more progressive with the departure of the
low pressure system on Thursday, with now most guidance showing
rain ending early Thursday and some sun returning by afternoon.
Highs should return to the 70s for most.

A cold front slides into the area and stalls Thursday night, but
may be accompanied by a few showers as it moves in. Lows staying
in the 60s near and southeast of I-95, upper 50s north and west.

The area starts relatively dry Friday morning despite the
stalled front in the vicinity, but likely won`t stay that way as
another low pressure developing to the southwest starts moving
northeastward along the front, bringing a risk of showers and
thunderstorms across the area later in the day and especially at
night. There is a modest severe weather risk mainly across
southern areas, outlined by a marginal risk from the SPC. Some
locally heavy rain is also possible mainly from I-95 north and
west, outlined by a marginal risk from the WPC. Temperatures-
wise, a little morning sun should help highs return to the 70s
for most on Friday, while clouds and showers/possible storms
Friday night help keep lows near 60 across much of the area.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
We probably are drying out early Saturday as the low pressure
from Friday night heads northeastward away from us. However, a
relatively strong cold front and upper trough will dive toward
us, arriving likely in the afternoon at some point, thus
resulting in a return of the risk of showers and t-storms. There
may be another severe weather risk with this front, but no
outlooks have been issued yet. Highs likely return to the 70s
for most, but probably a few degrees cooler than Thursday and
Friday as we start to get cold advection behind the departing
low.

The front clears the region quickly Saturday evening and we
should turn out dry for the night. A northwest breeze should
bring a notably cooler night, with temps falling into the 50s
near and southeast of I-95, 40s north and west.

High pressure starts to build in for Sunday, but lingering upper
trough could bring some clouds and a stray shower, mainly to the
Poconos. Like Saturday, highs will be mostly in the lower 70s.

High pressure should generally dominate Monday and Tuesday,
though with an impulse passing south of us Monday along the
upper trough which will still be lingering nearby, southern
areas could get a shower at some point. This moves away by
Tuesday, with rising heights and warming temps. Highs Monday
should be mostly in the mid-upper 70s while Tuesday should have
temps around 80.

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Rest of today...VFR ceilings lower to MVFR and eventually IFR
by about 18Z. Rain will be light initially with VFR visibility,
however this will lower through the afternoon from south to
north. East-northeast winds becoming east around 10 knots with
some gusts to 15-25 knots this afternoon (highest at KMIV/KACY).
Low confidence regarding the timing/details.

Tonight...IFR ceilings through most of the night, perhaps even
LIFR at times. Some improvement is possible late. Rain will
diminish from southwest to northeast overnight. East-northeast
wind 5-10 knots. Low confidence regarding the timing/details.

Outlook...

Sub-VFR conditions may linger for some time on Thursday as low
pressure moves away. VFR conditions likely dominate Thursday
night and Friday morning before sliding back below VFR late in
the day and at night as rain returns, with intervals of IFR
possible. Conditions likely start returning to VFR during the
day Saturday, with solid VFR Saturday night and Sunday.

&&

.MARINE...
Small Craft Advisory conditions are expected to develop over
the waters from south to north through the day today. By late
this afternoon, east wind will increase to 15-20 kt with gusts
as high as 30 kt. Seas will increase to 4-7 feet by late this
afternoon. Wind will decrease some overnight but seas will
remain elevated.

Outlook...

Small Craft Advisory conditions will gradually diminish during
the day Thursday. Conditions will remain below SCA levels
Thursday night through Friday night but then seas may start to
creep back up to SCA levels later Saturday. Sub-SCA conditions
then likely return by Sunday.

Rip Currents...

There is a MODERATE risk for the development of dangerous and
life threatening rip currents on both today and Thursday for
the Jersey Shore and for Delaware Beaches. Today, east winds
will average 15 to 20 mph along with breaking waves of 2 to 4
feet and a 5-7 period swell. On Thursday, winds turn offshore,
though with a lingering onshore swell, a MODERATE should
suffice.

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

&&

.TIDES/COASTAL FLOODING...
Some spotty minor tidal flooding remains possible for the
overnight high tide cycles for the next few days. Guidance is
trying to indicate some more widespread tidal flooding,
especially for tonight, though given how most of the models have
been too high with water levels, the current forecast was
adjusted to just below advisory thresholds. While onshore flow
continues and water builds up, astronomical tides are lowering
getting away from the New Moon, to the point where the thinking
is that they almost cancel each other out. Perhaps tide heights
tonight or a tenth of two higher, but not enough to trigger an
advisory at the moment.

For the Chesapeake Bay, no tidal flooding is expected.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 10 PM EDT this evening for ANZ430-
     431.
     Small Craft Advisory from 6 PM this evening to 6 PM EDT
     Thursday for ANZ450.
     Small Craft Advisory from 2 PM this afternoon to 6 PM EDT
     Thursday for ANZ451-452.
     Small Craft Advisory until 6 PM EDT Thursday for ANZ453>455.

&&

$$

SYNOPSIS...RCM
NEAR TERM...Cooper/Gorse
SHORT TERM...RCM
LONG TERM...RCM
AVIATION...Cooper/Gorse/RCM
MARINE...Cooper/Hoeflich/RCM
TIDES/COASTAL FLOODING...Hoeflich