757
FXUS61 KPHI 011810
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
210 PM EDT Tue Oct 1 2024

.SYNOPSIS...
An upper level low will cross the Mid-Atlantic states through
tonight. A weakening cold front will cross the region from west
to east Wednesday night. High pressure will reestablish itself
over the Northeast states Thursday and Friday, before a cold
front moves into the area Saturday. High pressure briefly affects
the area later Saturday into Sunday, before another cold front
moves into the area Sunday night into Monday.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
An upper level trough is slowly moving through our region this
afternoon to be offshore by this evening. At the surface, high
pressure to the north over eastern Quebec and a weak area of
low pressure off the Virginia/North Carolina coast will result
in onshore flow continuing and a relatively cloudy day overall.
As the trough moves through, a few places will have a brief
shower, mainly from Philadelphia on south.

No rain is expected tonight overall as the trough moves
offshore, though clouds will stick around until the cold front
comes through on Wednesday. Rather mild overnight lows are
expected due to the overcast skies, with mid to upper 50s and
low 60s anticipated. The weakening cold front will be located in
central Pennsylvania by late Wednesday afternoon. The main
impacts to our region will be a slight chance (20%) of light
rain showers confined to Berks Co, Lehigh Valley, and the
southern Poconos.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
The cloudy conditions of the near term will yield to better weather
for the end of the current week. Any showers that move across the
north/west areas Wed., with the weakening front, will be done by
evening. High pressure building in both at the sfc and aloft will
bring a fine end to the week. Temperatures will average a little
above normal both days with highs in the low/mid 70s most spots.
Seasonably cool overnight lows in the 50s most spots. Patchy
rural fog is possible during the predawn hours.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A great weather weekend is expected across the Middle Atlantic
region. An upper ridge across the Midwest will be advancing towards
our area while a surface high arrives from the Great Lakes. Not only
will both days feature plenty of sunshine, but temperatures will be
very mild for early October standards. Highs both days will be in
the mid/upper 70s with some low 70s for the far NW areas. Overnight
lows will be chilly with good radiational cooling developing.
Saturday morning will have lows in the 50s, but Sunday morning will
see plenty of low/mid 40s for the far NW areas and low 50s to upper
40s elsewhere. Some cooler guidance has some upper 30s for Mount
Pocono. We`ll have to monitor for possible frost wording in upcoming
fcsts.

Questions linger about how the weather will be early next week. The
operational models show a front crossing the area Monday, but what
happens as the front nears the coast vary. Yesterdays EC run has a
potent low pressure developing and spinning across the NJ/NYC areas
Monday/Tuesday. The overnight (00Z) EC continues that pattern. The
latest CMC/GFS models have a low developing farther north across New
England giving our area a frontal passage, but no prolonged rains.
Considering this, we`ll keep just a chance for showers Monday and
just have some slight chance pops (mostly north) for Tue. The high
temperatures Monday will be close to normal with upper 60s/low 70s
for highs. Readings Tuesday will be a little below normal, a taste
of fall.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.

This afternoon...Any MVFR ceilings should lift to VFR except
closer to the coast where they will remain in the MVFR category
through the day.

Tonight...Ceilings will lower to MVFR all areas by midnight.

Wednesday...VFR.

Outlook...

Wednesday night through Sunday... VFR. Patchy predawn fog possible.

&&

.MARINE...
A Small Craft Advisory is in effect through Wednesday for all
ocean zones. Seas will be around 5 to 7 feet, with gusts up to
25 kt possible.

No marine headlines on Delaware Bay as winds will be out of the
northeast around 10-20 kt.

Outlook...

Elevated seas may linger on the Atlantic coastal waters into the
Wednesday evening, so the SCA flag has been extended a bit to
cover that. Otherwise, winds and seas should stay below SCA
criteria through Sunday. Fair weather expected.

&&

.TIDES/COASTAL FLOODING...
No coastal flood advisories are currently in effect. Wind driven
surge has decreased. However, as we get closer to the new moon
on Wednesday, astronomical high tides are increasing. The net
effect is that tidal flooding is still a concern over the next
few days, but less certain and probably more marginal than the
tidal flooding over the last week.

For the NJ and DE Atlantic coast and the Delaware Bay,
widespread tidal flooding is not expected with the high tide
this morning. For the high tide this evening, it appears that
tide levels will fall just shy of advisory thresholds. However,
will be watching conditions on the back bays closely. Minor
tidal flooding is possible with the Wednesday morning high tide,
but current forecast tide levels are in most cases right at the
advisory threshold, so will watch tidal departure trends with
this mornings high tide before making a decision.

For the tidal Delaware River, no tidal flooding is expected,
except possibly right at the mouth of the river as it empties
into the bay, primarily with the high tide tonight.

for the Northeastern Chesapeake Bay, tide levels will be close to
minor flooding thresholds at Claiborne for high tides this afternoon
and Wednesday afternoon, but look to fall just short. Further up
the bay at Tolchester, the threat is even lower.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 10 PM EDT Wednesday for ANZ450>455.

&&

$$

SYNOPSIS...Franklin/Johnson
NEAR TERM...Franklin/Hoeflich
SHORT TERM...OHara
LONG TERM...OHara
AVIATION...Franklin/OHara
MARINE...Franklin/OHara
TIDES/COASTAL FLOODING...Staff