906
FXUS61 KPHI 070812
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
412 AM EDT Tue May 7 2024

.SYNOPSIS...
A cold front moving southward into the area early this morning will
become nearly stationary for a time as it reaches Delmarva. It will
then push back to the north as a warm front as an area of low
pressure tracks by to the north Tuesday night into Wednesday. This
will be followed by a stronger area of low pressure moving across
the region Thursday. This low will track east of the area Friday
with a couple upper level disturbances then tracking through the
area this coming weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
A weak cold front is moving through the area this morning and is
located over the northern Lehigh Valley and northern NJ. Out
ahead of the front, the surface and low levels are quite
stagnant and saturated, which has resulted in the formation of
fog south of the front. Behind the front, skies are clearing out
and dewpoints falling-Mount Pocono currently has the highest
visibility within the CWA at the moment (quite the rarity). Low
clouds and fog will quickly dissipate by the mid to late
morning. Don`t anticipate needing a Dense Fog Advisory, but will
continue to see how things trend.

Further south over far South Jersey and southern Delaware, some
showers are moving through as a shortwave slides by to the south.
Rain will move out by daybreak or so.

For today, the cold front slowly inches south, getting to about the
Philadelphia metro before stalling out and eventually starting to
lift north as a warm front this afternoon and evening. North of
Philadelphia will actually see the sun for the first time in days
while it remain mostly cloudy south of the city. It will be a mainly
dry day though some showers or an isolated thunderstorm can`t be
ruled out within the warm sector (Delmarva and far SE PA). Not
expecting anything much from this and PoPs are only 15-30%. Highs
will creep into the mid to upper 70s.

Tonight starts dry but an area of low pressure will move through the
Great Lakes with a frontal system approaching our region. This will
bring another period of rain overnight. Rain will mainly be confined
to areas north of Philadelphia, though some showers remain possible
regionwide. Can`t rule out a rumble of thunder, though
instability is relatively meager. Looks at most to be just some
embedded thunder. Rainfall amounts up to a quarter of an inch
are anticipated. Overnight lows will be in the upper 50s/low
60s.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
A fairly busy/active weather pattern persists across the area
through the short term period. For Wednesday, a weak area of low
pressure passes by to the north as it moves from upstate NY into New
England. An initial round of showers and storms associated with the
system`s warm front will be moving out through the first part of the
morning with skies then clearing and temperatures shooting up as the
area breaks into the system`s warm sector. Expect afternoon highs
generally in the low to mid 80s across the area except 70s right
near the immediate coast and over the southern Poconos. Dew points
will climb into the low to mid 60s through the late morning but then
should actually start to come down in the afternoon as a very weak
cold front starts to move through and the winds turns more westerly.
During the warmest part of the day dew points should be mainly in
the upper 50s to low 60s which isn`t too high. There could be some
isolated afternoon showers/storms developing but these would be few
and far between as it should otherwise be dry through the latter
part of the day. It is worth mentioning though that should any
showers/storms develop they could become severe as winds aloft will
will be quite strong with inverted-V soundings in the lower levels.
Damaging winds would be the threat. As a result of this set up, it
will also be a breezy in the afternoon with west winds gusting 20 to
25 mph.

For Wednesday night, initial low moves out to sea as it passes east
of New England with a new low starting to move into the midwestern
states. This will eventually push a warm front towards the area by
Thursday morning which could start to bring in some showers/storms
towards sunrise across eastern PA and Delmarva however the
trend has been slower with this.

Thursday is shaping up to be more unsettled as this next area of low
pressure referenced above moves across the region bringing more
widespread showers and storms. That said, there is still a lot
of uncertainty on the track of this system which will have
implications both on the high temperatures and the severe
weather threat. The overall trend though has been for a track
farther south favoring a low tracking eastward near Delmarva
which would limit how far north the warm front gets. Deep layer
shear will be quite strong meaning anywhere near and south of
the warm front will have a heightened severe weather threat
Thursday afternoon into the evening but right now the most
favored area looks to be over Delmarva and southern NJ. This
could change, however, if the system and its warm front tracks
farther north. Currently expect highs Thursday ranging from the
upper 60s/low 70s north to the mid/upper 70s south but again,
this is contingent on the track of the low. With an overall
slower trend with the system, showers/storms could last through
a good portion of Thursday night although any severe weather
threat should diminish with time.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
In the big picture, the weather pattern will remain on the unsettled
side through the weekend as a long wave upper level trough lingers
in the east. This should be followed by a drying trend into early
next week. Getting into the details, on Friday surface low pressure
will track east of the region while an upper level trough axis lags
behind and pushes through the mid Atlantic. This will keep chances
for showers in the forecast, especially north (POPs ranging from
around 40 percent south to 70 percent north), under generally
overcast skies. It will also be cooler with highs mostly in the 60s
to low 70s.

Heading into Saturday, chances for showers diminish, as the initial
shortwave trough moves out and shortwave ridging builds in briefly
for a time. However by late day the next disturbance will be
approaching and this could bring some more showers back into the
region, especially over eastern PA. So we keep the mention of shower
chances in the forecast but POPs are generally only in the 20 to 30
percent range. Expect highs mainly in the 60s under a mix of sun and
clouds so certainly not a washout. A better chance for showers
arrives by Sunday as the next shortwave trough swings through
(POPs 40 to 60 percent) and there will also be more in the way
of cloud cover.

Finally by early next week it should start to trend warmer and drier
as the upper trough moves out and the flow over the east becomes
more zonal.

&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas...

Rest of Tonight...Primarily MVFR/IFR with fog and low ceilings. LIFR
VSBYs possible at KABE but think that should break soon as a cold
front brings in some drier air. Conditions drop to LIFR at KACY/KMIV
where the fog will be more widespread and some marine stratus moves
onshore. Winds generally light and variable, 3 kt or less. Moderate
confidence overall.

Tuesday...Conditions quickly lift to VFR with fog mixing out and any
lingering low ceilings lifting. All terminals outside of KMIV/KACY
should be back to VFR by the late morning (12z-14z or so). Lower
visibilities and ceilings persist at KMIV/KACY through midday or so,
though expecting VFR for the afternoon. Very light flow out of the
north/northeast in the morning will shift to a more southwesterly
flow in the afternoon. Wind speeds 5 kt or less. Moderate confidence
overall.

Tuesday Night...MVFR/IFR conditions redeveloping with low clouds and
patchy fog. Southerly winds 5 kt or less. Low confidence in timing
and extent of restrictions.

Outlook...

Wednesday through Saturday...Sub-VFR conditions favored at night in
fog/mist and stratus, while VFR conditions overall during the day
for most days. Chances for SHRA/TSRA throughout the period with sub-
VFR conditions. More widespread SHRA with scattered TSRA Thursday
afternoon and evening.

&&

.MARINE...
No marine headlines expected through tonight as seas will be around
3 feet and winds less than 10 kt. Some patchy fog possible on the
waters this morning. Will monitor observations to see if a Marine
Dense Fog Advisory is needed.



Outlook...

Wednesday through Saturday...Overall, sub-SCA conditions
through the period. Scattered showers and thunderstorms will
result in locally higher wind gusts and seas, with biggest
impacts coming on Thursday afternoon and evening.

&&

.TIDES/COASTAL FLOODING...
Tidal ranges increasing this week as the new moon arrives this
evening. Limited onshore flow means that there won`t be much in
the way of serious flooding concerns, but still widespread
minor tidal flooding is expected with the high tide this evening
for Atlantic coastal zones, the Delaware Bay, and the tidal
Delaware River. A Coastal Flood Advisory has been issued for
these areas. Another round of minor coastal flooding is likely
for these areas with the high tide cycle Wednesday night.

Flooding is not expected for our Maryland zones along the
Chesapeake.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Coastal Flood Advisory from midnight tonight to 5 AM EDT
     Wednesday for PAZ070-071-104-106.
NJ...Coastal Flood Advisory from 10 PM this evening to 2 AM EDT
     Wednesday for NJZ016.
     Coastal Flood Advisory from 7 PM this evening to 1 AM EDT
     Wednesday for NJZ012>014-020>027.
     Coastal Flood Advisory from midnight tonight to 5 AM EDT
     Wednesday for NJZ017>019.
DE...Coastal Flood Advisory from 10 PM this evening to 2 AM EDT
     Wednesday for DEZ001.
     Coastal Flood Advisory from 7 PM this evening to 1 AM EDT
     Wednesday for DEZ002>004.
MD...None.
MARINE...None.

&&

$$

SYNOPSIS...Fitzsimmons
NEAR TERM...Hoeflich
SHORT TERM...Fitzsimmons
LONG TERM...Fitzsimmons
AVIATION...Fitzsimmons/Hoeflich
MARINE...Fitzsimmons/Hoeflich
TIDES/COASTAL FLOODING...