826
FXUS61 KPHI 031839
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
239 PM EDT Fri May 3 2024

.SYNOPSIS...
High pressure builds into New England with onshore flow setting up.
A series of cold fronts approaches for the weekend, with the second
(and stronger of the two) front stalling out nearby by early next
week. The stalled front lifts north as a warm front at some point in
the Tuesday/Wednesday timeframe, bringing a return to above normal
temperatures.

&&

.NEAR TERM /THROUGH SATURDAY/...
235 PM...It`s a challenging near term forecast due to different
competing forces. On the one hand, an expansive ridge of high
pressure is building into eastern Canada with the southwestward
periphery of this feature extending back into the mid Atlantic.
And in fact guidance actually depicts this feature strengthening
slightly over our area during the next 24 hours. Meanwhile
though, this ridge has resulted in easterly flow that has
brought in a low deck of some marine stratus into much of NJ,
DE, and even extending at times into portions of eastern PA.
Finally, there is a frontal system that`s approaching from the
west with some showers however it will take some time for these
showers to get into the area over the weekend as it runs up
against the ridge in place. The upshot of all this is that skies
are variable across the area this afternoon with the marine
stratus starting to mix out and retreat back to the east just
within the past hour or two while at the same time some high
cirrus has been moving in from the west. It`s also a much cooler
day compared to yesterday with temperatures as of 2 PM only in
the 50s and 60s.

As we go through the rest of this afternoon into the evening
expect that we`ll continue to see variable skies with low
stratus continuing to be most persistent near the coast while
western parts of the CWA over eastern PA continue to see some
filtered sunshine through the high clouds. It will remain precip
free though through the evening. Overnight, however, shortwave
energy will ride over the top of the upper level ridge centered
over the east and help to push showers from the west closer to
the region. This could bring a few light showers into parts of
Delmarva and eastern PA by daybreak. Otherwise, clouds thicken
through the night with lows getting down mainly into the upper
40s to around 50.

For Saturday, low pressure moves eastward towards the Great
Lakes driven by an advancing upper level trough. As this occurs,
showers well ahead of it will continuing to try making inroads
into our area while running up against the stubborn surface high
that will be slow to move out. The upshot is some scattered
showers will likely make it in at times, especially over eastern
PA and Delmarva and especially getting into the second half of
the day (POPs here by late day generally 40 to 60 percent).
Otherwise it will be a mostly cloudy and cool day with
continuing easterly winds and highs only making it to the upper
50s to low 60s.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
Not the best weekend ahead weather-wise but not necessarily terrible
either. A weakening cold front will approach on Saturday, with some
showers moving through ahead of it. Best chance to see showers will
be west of the I-95 corridor, but can`t rule out some light rain
across the area. Otherwise, it will be cloudy and cool with a steady
onshore flow. Temperatures will be in the upper 50s/low 60s. With
the maritime airmass in place, not expecting much in terms of
thunderstorms as it should remain rather stable.

Showers become more widespread by Saturday Night through Sunday
Night as a stronger cold front approaches from the west. Highest
PoPs are concentrated in the Sunday morning timeframe. Some elevated
instability could move in for Sunday afternoon/evening but not
expecting any severe weather, and just some rumbles of thunder mixed
in with passing showers. The maritime airmass will continue to have
a grip on the region, though flow turns a bit more southerly in
southern Delmarva. The result will be another day in the upper
50s/low 60s for most, with upper 60s/70s in southern Delaware and
along the southern Eastern Shore.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Unsettled conditions are expected for most of next week as a
boundary stalls out over the region. Rain chances are in the
forecast each day during the week as several waves of low pressure
are expected to ride along the boundary. Each day won`t be a washout
by any means, and PoPs are generally around 20-40% Monday/Tuesday,
with the highest coming in the afternoon. Not much instability will
be present, with the threat of any thunderstorms/severe weather
being low. Temperatures both days will be in the mid to upper 70s,
with some 80s possible on Tuesday.

The boundary looks to lift north by Tuesday in the form of a warm
front, putting the region in the warm sector. Looking at a period of
above normal temperatures for Wednesday/Thursday with upper 70s/low
to mid 80s anticipated. A few shortwaves will move through, which
will spark off some showers and thunderstorms, mainly in the
afternoon/evening both days. More instability will be present, so we
will have to watch this window, though too early to tell if/how
impactful any convection will be.

&&

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

Through this afternoon...Mainly MVFR predominating at ACY, MIV,
TTN, and PNE due to low stratus. Otherwise mainly VFR with a
scattered deck around 2500 feet. East winds 10 to 15 knots with
some gusts to around 20 knots possible. Moderate confidence.

Tonight...The marine stratus should result in MVFR cigs or lower
eventually predominating by the overnight period with conditions
lowering through the evening around PHL but likely not until the
overnight at RDG and ABE. IFR cigs likely overnight at MIV and
ACY. East winds 5 to 10 kt. Low confidence.

Saturday...Mainly MVFR in the morning with some improvement in
the afternoon to VFR except at MIV and ACY where MVFR may
continue. East winds around 10 knots. Low confidence.

Outlook...

Saturday Night...Restrictions expected with steady rain moving
through, with CIGs as low as IFR possible.

Sunday...Restrictions expected with showers/low clouds moving
through. CIGs as low as IFR possible.

Sunday Night...Restrictions possible with 40-60% chance of showers
and 15-25% chance of thunderstorms.

Monday through Tuesday...Primarily VFR though some restrictions
possible with any showers. 20-40% chance of showers through this
period.

&&

.MARINE...
A Small Craft Advisory continues through this afternoon over our
ocean zones as seas remain around 5 to 6 feet with winds gusting
20 to 25 knots. These conditions should diminish early this
evening with seas diminishing to 10 to 15 knots and seas around
3 to 4 feet. Little change is expected on Saturday. It will also
be mainly cloudy over the waters through Saturday with some
patchy fog possible at times.

Outlook...

Saturday night through Tuesday...No marine headlines
anticipated. Showers/thunderstorms possible on the waters Sunday
through Sunday night.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 6 PM EDT this evening for
     ANZ450>455.

&&

$$

SYNOPSIS...Hoeflich
NEAR TERM...Fitzsimmons/MPS
SHORT TERM...Hoeflich
LONG TERM...Hoeflich
AVIATION...Fitzsimmons/Hoeflich/MPS
MARINE...Fitzsimmons/Hoeflich/MPS