-- Discussion containing changed information from previous version are highlighted. --
169
FXUS61 KPHI 081807
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
207 PM EDT Wed May 8 2024

.SYNOPSIS...
An area of low pressure tracks by to our north early this morning.
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 additional upper level disturbances tracking through the
area this weekend. A warmer, drier pattern looks to return early
next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
Morning convection has now moved offshore. Lingering clouds
will diminish by the afternoon allowing temperatures to rise
quite a bit. Highs will be the warmest of the week, with
temperatures ranging from the upper 70s well north and west to
the mid to upper 80s south away from the cooler waters. It will
become breezy with southwest to west winds gusting 20-25 mph.
Earlier it had looked like we could see some additional isolated
storms in the afternoon but at this point it looks quite dry
through the column so we keep afternoon POPs below 15 percent.
That said, if something did manage to form it could produce
gusty winds given inverted-V soundings.

As we head into tonight, initial area of low pressure continues
moving east off the coast of New England and out to sea. This will
push a weak cold front offshore through the evening. Meanwhile by
the overnight period the next wave of low pressure will be
approaching as it moves eastward through the midwestern states and
this will start to push the front back to the north as a warm front.
Clouds will once again be on the increase by the late overnight and
it`s possible we could see some showers start to enter the region
towards dawn, however the trend has been slower with these arriving
later. Expect lows ranging from the 50s north to the low 60s south.

Thursday is still shaping up to be more unsettled as this next area
of low pressure referenced above moves across the region bringing
additional rounds of showers and storms. What`s worth noting though
is that the model guidance continues to trend farther south with the
track of this system...likely tracking the low east through Delmarva
or perhaps even slightly to the south of here. This should tend to
limit the threat for severe weather Thursday afternoon to Delmarva
and perhaps extreme SE PA and southern NJ. Confidence on exactly
where this threat sets up though is still not that high as there
could be further changes to the track of the low. If it keeps
trending farther south, this could keep the severe weather threat
even south of Delmarva while a trend back to the north would allow
the warm front to get farther north into PA and NJ leading to a more
expansive severe threat. Right now the Storm Prediction Center has
Delmarva in a SLIGHT risk for severe storms for Thursday with a
narrow area of a MARGINAL risk north of here clipping SE PA and
southern NJ. One thing to point out though is that both speed and
directional shear will be quite strong near the track of the low so
if there is enough instability that makes it into the area, all
threats will be on the table...Damaging winds, large hail, and even
the potential for a tornado or two. The clouds and showers/storms
will keep it cooler for Thursday with highs generally in the 70s.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
With an overall slower trend with the system, showers/storms could
last through a good portion of Thursday night (PoPs mainly 55-65
percent) although any severe weather threat should diminish through
the nighttime hours with the loss of daytime heating. Lows generally
in the low 50s.

On Friday, our earlier 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 60
percent north), under generally overcast skies. It will also be
cooler with highs mostly in the upper 50s to mid 60s. Shower chances
continue into Friday night but should gradually diminish as the
upper level trough pushes through later overnight. Lows mainly in
the mid-upper 40s.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
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. 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 Saturday night into Sunday as the next shortwave trough
swings through (POPs 30 to 50 percent) and there will also be more
in the way of cloud cover.

Finally by early next week it should start to trend warmer (highs
mainly in the upper 70s) and drier (PoPs generally less than 25
percent) as the upper trough moves out and the flow over the east
becomes more zonal.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas...

Rest of today (through 00Z)...VFR with westerly winds 10 to 15
gusting 20 to 25 knots. High confidence.

Tonight...Mainly VFR with winds becoming light and variable.

Thursday...Shower/storms likely along with lowering cigs and
visbys down at least MVFR at times. Winds generally east around
10 knots.

Outlook...

Thursday night through Sunday...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.
-- End Changed Discussion --

&&

.MARINE...
Conditions will remain below Small Craft Advisory levels through the
day today but expect some fog over the waters through the first part
of this morning...especially off the coast of southern NJ and
Delaware. The fog should diminish by later in the morning as some
showers move over the waters.

It will be quiet on the waters tonight but then expect more rounds
of showers with some storms as well during the day Thursday as the
next low approaches. East winds increase through the day to around
15 gusting 20 to 25 knots by late day. Seas should generally be
around 3 feet through today and Thursday.

Outlook...

Thursday night through Sunday...Overall, mainly sub-SCA conditions
expected through the period but winds and seas may briefly increase
to around 20-25 knots and 4-5 feet, most likely later in the day on
Friday.

&&

.TIDES/COASTAL FLOODING...
Tidal ranges increasing this week with the new moon on Tuesday
evening. Limited onshore flow means that there won`t be much in the
way of serious flooding concerns, but still another round of
widespread minor coastal flooding is expected for Atlantic coastal
zones, the Delaware Bay, and the tidal Delaware River with the high
tide cycle tonight. Therefore, another Coastal Flood Advisory is in
place for these areas as a result. Additional rounds of minor
coastal flooding remain possible with the evening/overnight high
tides through the end of the week.

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

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Coastal Flood Advisory from 1 AM to 6 AM EDT Thursday for
     PAZ070-071-106.
NJ...Coastal Flood Advisory from 10 PM this evening to 2 AM EDT
     Thursday for NJZ016.
     Coastal Flood Advisory from 8 PM this evening to 2 AM EDT
     Thursday for NJZ012>014-020>027.
     Coastal Flood Advisory from 1 AM to 6 AM EDT Thursday for
     NJZ017>019.
DE...Coastal Flood Advisory from 10 PM this evening to 2 AM EDT
     Thursday for DEZ001.
     Coastal Flood Advisory from 8 PM this evening to 2 AM EDT
     Thursday for DEZ002>004.
MD...None.
MARINE...None.

&&

$$

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