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195
FXUS61 KPHI 052047
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
447 PM EDT Sun May 5 2024

.SYNOPSIS...
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An east to southeasterly flow off the Atlantic ocean will
result in cloudy weather through Monday morning with areas of
light rain and drizzle. A cold front will work its way through
the region late Monday and Monday night. This boundary will
become stationary over the area through the mid- week period. A
series of disturbances will track along this boundary through
the middle of the week. A stronger area of low pressure moves
through the region on Thursday, followed by a cold front on
Friday.
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&&

.NEAR TERM /THROUGH MONDAY/...
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144 PM discussion...
Weak warm advection overruning a very moist and cool marine
layer will keep low clouds and light rain or drizzle for most
locations through Monday morning. As a shortwave moves over the
region this afternoon, showers along and west of the Delaware
Valley will spread eastward into coastal areas.

The bulk of the rain moves out early this evening, but another
weak trough approaching tonight will reinforce lift and
generate additional scattered showers. Some of the model
soundings show some elevated instability, so can`t rule out some
lightning strikes late tonight, mainly within Delmarva and the
southern half of New Jersey. Some patchy fog is possible with a
moist boundary layer, greatest chance mainly north and west of
the Philadelphia metro. It will be a mild night, with lows in
the mid to upper 50s/low 60s.

Winds become southerly Monday morning ahead of a cold front that
will usher an increasingly humid airmass into the region with
surface dewpoints rising into the 60s. Any fog in the morning will
lift and dissipate by midday. The cold front passes through the
region Monday afternoon and Monday evening. Some shortwave
energy passing through the region will help kick off widely
scattered afternoon showers and thunderstorms, mainly across
the southern portions of the forecast area.
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&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
Periods of unsettled weather are expected early in the week as
a cold front will move to the south of the area on Monday night,
then stall to our south into Tuesday, then begin lifting back
north Tuesday night. Showers will be possible on Monday night
near the front as it sags southward, but Tuesday may end up
being dry for many areas since we will be north of the front.
There will still be a chance of showers and isolated
thunderstorms for the southern third to half of the area later
in the day as they will be closer to the front. On Tuesday
night, the area with the greatest chance for showers and
isolated thunderstorms shifts northward as the front lifts back
to the north and short wave/vorticity impulse moves across the
northern areas.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Unsettled weather continues for the second half of the week. On
Wednesday, an area of low pressure will move our of the Great
Lakes and into the northeastern states, eventually bringing a
cold front to the area. After a round of showers and isolated
thunderstorms early in the day Wednesday across the northern
areas, much of the day into the evening hours could be mostly
dry for many areas as the front stalls near the area. However,
this dry weather will not last as showers and isolated
thunderstorms are expected to increase later Wednesday night
into Thursday and continue through Friday as multiple waves of
low pressure move along the stalled boundary across the Mid-
Atlantic region, before the final low and cold front move
offshore of the Mid Atlantic coast Friday into Friday night.
Although the forecast has a chance of showers for next weekend,
drier weather may return as high pressure could begin to affect
the area.

&&

.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
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The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

144 PM discussion...
Rest of today...Ceilings at or below 1Kft this
afternoon with ceilings 3-4Kft across southern Delaware and
southeastern New Jersey. Highest concentration of showers should
move through the Lehigh Valley and Delaware Valley.

Tonight...Low clouds and areas of fog. South to southeast wind
around 5 kt.

Monday...Cloud deck at or below 1Kft in the morning with areas
of fog. Ceilings rise to 1-2Kft by midday. winds become
southwesterly around 10 knots.

Outlook...

Monday night...Areas of sub-VFR conditions with a chance
of showers and thunderstorms.

Tuesday...Areas of VFR to MVFR conditions with a chance of showers
and thunderstorms.

Tuesday night...Areas of IFR developing with showers likely with a
chance of thunderstorms.

Wednesday-Wednesday night...Conditions may improve to VFR with a
chance of showers and thunderstorms.

Thursday-Friday...Sub-VFR conditions likely with showers and
possible thunderstorms.
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&&

.MARINE...
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144 PM discussion...
No marine headlines expected through Monday as seas will be 2
to 4 feet with winds from the east to southeast at 10 to 20 kt.
Periods of showers expected, with a 15-20% chance of
thunderstorms early Monday morning.

Outlook...

Monday night-Friday...Conditions likely to remain below Small
Craft Advisory levels for much of the period. Winds may gust
around 20 knots at times, and seas may approach 5 feet Thursday
night.
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&&

.TIDES/COASTAL FLOODING...
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Approaching new moon middle of this week promises to bring very
high astronomical tides. It will thus be very difficult to avoid
at least some advisory level coastal flooding in some locations,
and a few spots might hit moderate even with weakening onshore
flow. Will continue to monitor, but coastal flood advisories
look likely by late Tuesdady.
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&&

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

&&

$$

SYNOPSIS...Franklin/MPS
NEAR TERM...Franklin/Hoeflich
SHORT TERM...Robertson
LONG TERM...Robertson
AVIATION...Franklin/Hoeflich/Robertson
MARINE...Franklin/Hoeflich/Robertson
TIDES/COASTAL FLOODING...RCM