225
FXUS61 KPHI 050716
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
316 AM EDT Sun May 5 2024

.SYNOPSIS...
A warm front will lift north through the region today, and then
a cold front works 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.

&&

.NEAR TERM /THROUGH TONIGHT/...
A cloudy, showery, and dreary Sunday morning is ongoing. Weak
warm advection overruning a very moist and cool marine layer
will result in showers continuing for most of today. Forcing
will be maximized over the Lehigh Valley, where the bulk of the
showers will be through the morning. As a shortwave moves over
the region, the area of showers will push east through the
afternoon and evening. Precipitation will be rather light
overall and more of a nuisance than anything. Outside of
showers, it will be a cloudy and cool day yet again.
Temperatures will be in the upper 50s/low 60s, though as a warm
front tries to push north, some areas in lower Delmarva will
climb into the upper 60s and perhaps get near/above 70.

The bulk of the rain moves out late this evening, but a cold
front approaching tonight will reinforce lift and generate some
further showers. Some of the model soundings show some elevated
instability, so can`t rule out a rumble of thunder late tonight,
mainly within Delmarva and the southern half of New Jersey
(basically along and south of that aformentioned warm front).
Not expecting any severe weather or anything like that though.
Some patchy fog is possible with a moist boundary layer. Fog
chances are maximized mainly north and west of the Philadelphia
metro (basically north of the warm front). It will be a mild
night, with lows in the mid to upper 50s/low 60s.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Cold front will be west of the area Monday morning. Southerly
flow ahead of that front will usher an increasingly humid
airmass into the region with surface dewpoints rising into the
60s. Areas of fog will develop in the morning, and then will
lift and dissipate by midday or so. The cold front passes
through the region Monday afternoon and Monday evening. Some
shortwave energy passing through the region will help kick off
afternoon and evening showers and thunderstorms, mainly across
the southern portions of the forecast area.

The front becomes stationary south of the region Monday night
through Tuesday night. High pressure builds north of the region,
and an onshore flow develops, bringing somewhat cooler and drier
air down into the region. Another disturbance approaches from
the west late Tuesday and Tuesday night, touching off another
round of scattered showers and thunderstorms over the region.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A prolonged period of unsettled weather on tap for the latter
part of the new week. A series of frontal boundaries and weak
low pressure systems will pass through the region during this
time. The first system is an area of low pressure that will pass
north of New Jersey Wednesday morning, and this will drag a
cold front through the region late in the day and at night. Some
rain is possible in the morning, and then another round of
showers and mostly isolated thunderstorms will affect the area
Wednesday afternoon and Wednesday evening.

The next area of low pressure will organize and develop over
the Midwest, and a warm front will develop out ahead of this
system and lift towards the local area late Wednesday
night/early Thursday morning. This will touch off some more
showers and isolated thunderstorms during this time. A secondary
low will form over the Mid-Atlantic ahead of the primary low,
and this low works its way across the region Thursday afternoon
and Thursday night. More widespread showers and scattered
thunderstorms will affect the area during this time.

The primary low passes north of the region on Friday with yet
another round of showers as a cold front passes through the
region.

Temperatures during the period will start out warm with highs
in the 80s on Wednesday,and then temperatures will trend closer
to normal on Thursday and Friday.

&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Early this morning...A few holdouts still with MVFR CIGs but
would expect all terminals to go down to IFR within the next two
hours and remain that way through the morning. Visibility
should actually stay up at 6 miles or more given a steady east
wind keep things just mixed enough to preclude fog development.
East wind at 5-10 kt. Moderate confidence overall.

Today...IFR to start for most, though ceilings could lift a
little bit to MVFR especially at KMIV/KACY for the afternoon.
Most of the guidance has these lifting ceilings falling just
short of the I-95 corridor, but cannot rule out a brief period
of MVFR there. More steady showers should move through the
Lehigh Valley, keeping IFR conditions there for most of the day,
with some visibility restrictions. Winds out of the southeast
around 10 kt. Low confidence.

Tonight...IFR conditions expected with the potential for LIFR
(30-50%) CIGs. Some patchy fog also cannot be ruled out, but any
fog would likely come after 06z and be more confined to
KABE/KRDG/KTTN. South/southeast wind around 5 kt. Low
confidence.

Outlook...

Monday through Thursday...Unsettled weather on tap for most of
the new week. Overall, VFR during the day, but sub-VFR
conditions in SHRA from time to time. Nighttime sub-VFR
conditions in fog/stratus also expected. Best chances for
widespread SHRA and scattered TSRA will be Thursday afternoon.

&&

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

Outlook...

Monday through Thursday...A prolonged period of sub-SCA
conditions. VSBY restrictions in fog throughout the week,
especially at night. Best chances for widespread showers on
Thursday afternoon.

&&

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

&&

$$

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