043
FXUS61 KPHI 031336
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
936 AM 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 TONIGHT/...
935 AM...High pressure to our north over eastern Canada has
resulted in an easterly flow over the area and this has been
advecting some marine stratus westward through the coastal plain
into parts of eastern PA just within the past couple hours. As
of mid morning, this stratus has worked about as far west as
Northeast Philadelphia (PNE) and could even make it a bit
farther west through the late morning before starting to retreat
for a time this afternoon. Due to this trend we`ve generally
increased sky cover in the forecast with the mid morning update
as we also still have some cloud cover that will be arriving
from the west by later today.

The onshore flow has also resulted in a much cooler airmass
spreading into the region. Highs will be much colder compared
to Thursday, topping off in the mid to upper 60s for most of the
region, and in the upper 60s to low 70s for far western
portions of the forecast area. For coastal areas, onshore flow
will keep temperatures in the 50s.

Low pressure approaches from the west tonight. Most of the
region will remain dry as high pressure hangs tough along the
coast, but some showers may move into far western portions of
the forecast area prior to daybreak Saturday.

&&

.SHORT TERM /SATURDAY 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 THURSDAY/...
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 /14Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Today...Low stratus will bring restrictions through the day at
ACY where it`s likely to stay IFR through the early afternoon
before lifting to MVFR. MIV, TTN, PNE, ABE, and even PHL also
likely to see at least times of MVFR cigs through early this
afternoon due to the stratus having advected westward just
within the past few hours this morning. Moderate confidence on
the overall trend but low confidence regarding how far west the
MVFR cigs make it around the greater Philadelphia area.

Tonight...VFR for most of the night for most of the terminals,
lowering to MVFR at KACY/KMIV late. E winds 5 to 10 kt. Low
confidence.

Outlook...

Saturday...Mainly VFR. Some MVFR restrictions possible later in the
day especially at KRDG/KABE.

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 tightening easterly pressure gradient will develop on the waters
today, and E winds will increase to 15 to 20 kt with gusts up to 25
kt for most NJ and DE ocean waters. Seas will build to around 5 ft.
Will go ahead and hoist a Small Craft Advisory for all ANZ451-455
from 8am to 4pm. Sub-SCA conditions for DE Bay today and tonight.
Sub-SCA conditions for the ocean tonight.

Patchy fog expected on the ocean waters today and tonight with 1
to 3 NM VSBYs.

Outlook...

Saturday 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 4 PM EDT this afternoon for
     ANZ451>455.

&&

$$

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