989
FXUS61 KPHI 071307
AFDPHI

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

.SYNOPSIS...
A cold front moving southward into the area 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/...
Latest observations still show some light fog hanging
around. Reading, Millville, and Atlantic City were all reporting
4 miles. This fog is expected to dissipate shortly.

As we move through today, a cold front will slowly inch 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. Maybe a few locales touch 80.

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 /13Z TUESDAY THROUGH SATURDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas...

Today...Conditions are improving to VFR with Reading, Millville,
and Atlantic City lagging a bit. All terminals should be back
to VFR by 15z or so. 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.

Tonight...MVFR/IFR conditions redeveloping with low clouds and
patchy fog. Some rain expected after midnight, with the heaviest
from Philadelphia on north. 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/Kruzdlo
SHORT TERM...Fitzsimmons
LONG TERM...Fitzsimmons
AVIATION...Fitzsimmons/Hoeflich/Kruzdlo
MARINE...Fitzsimmons/Hoeflich
TIDES/COASTAL FLOODING...PHI Staff