677
FXUS61 KPHI 101035
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
635 AM EDT Fri May 10 2024

.SYNOPSIS...
Multiple waves of low pressure will affect the area today
through Sunday bringing a generally unsettled weather pattern.
High pressure builds south of the Mid-Atlantic region Sunday
night into Monday. Another area of low pressure may affect the
area with more unsettled weather by the middle of next week.

&&

.NEAR TERM /THROUGH SATURDAY/...
635 AM...As of early this morning, low pressure was centered
near the coast of Virginia along an associated east to west
oriented frontal boundary. Meanwhile in the upper levels a slow
moving positively tilted long wave trough was centered near the
eastern Great Lakes. The combination of these features will
continue to bring multiple waves of rain and showers to the area
through the day today. In terms of the details, at this point
an initial round of rainfall that included some embedded thunder
has moved off the coast with parts of the area over Delmarva
into SE PA and southern NJ in a lull. However more rain/showers
are off to the east over central PA and will arrive in the area
by later this morning and then continuing off/on through the
afternoon...heaviest and steadiest over eastern PA and adjacent
portions of NJ. The gradient between a high building in to the
north and east and the low to the south will also lock in brisk
east/northeast winds 15 to 20 gusting upwards of 25 to 30 mph.
This will add to the rawness of the day with highs for most
areas remaining stuck in the 50s (in the Poconos it may not get
out of the 40s).

As we go into tonight, the upper trough finally sweeps eastward
off the coast taking the surface low with it. This will bring
the steadier rain to an end through the evening from west to
east but there may be some patchy lingering drizzle into the
overnight under a low overcast. Total rain amounts by this time
should be generally in the .50 to 1.0 inch range except some
higher totals of up to 1.25 inches possible over the southern
Poconos into NW NJ. This isn`t expected to cause any major hydro
concerns. Otherwise, some clearing may finally occur towards
dawn Saturday as the winds turn more northerly. It will be a
chilly night with lows mostly in the 40s and even some upper 30s
possible in the southern Poconos.

For Saturday, we`ll get a brief respite in the unsettled
weather as shortwave ridging builds in. In fact most areas
should also see a little sun as the low stratus should start to
break up before clouds increase again by late day ahead of the
next system. The daytime hours should stay mainly dry though
with just a slight chance for some late day showers over our far
western zones from Berks County into Lehigh Valley. Expect
highs mostly in the low to mid 60s except 50s near the coast
and over the southern Poconos.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
Little change with the Friday AM forecast update as the unsettled
weather pattern will continue through Sunday. By Saturday
evening, the next wave of low pressure will arrive out of the
Great Lakes, increasing chances for showers, particularly west
of the Philly at night, and centered more on Philly during the
day Sunday. Showers continue to move into the region Sunday
(PoPs 55-65 percent) with lows again in the mid- upper 40s.
Highs will be cooler on Sunday, with 50s to near 60 common.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A brief period of dry weather is expected beginning Sunday
night and continuing into Monday as high pressure briefly builds
to the south of the Mid Atlantic region. This dry weather will
only be brief as rain chances will begin to increase Tuesday
into Wednesday as a storm system approaches from the southwest.
Beyond this time it should trend drier by Thursday.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...

Through today...Periods of rain and drizzle continuing today
with cigs becoming predominately IFR by mid morning. IFR should
then predominate for most of the rest of the day accept some
improvement to low MVFR possible by late day. East/northeast
winds 10 to 15 gusting at times 20 to 30 knots. Moderate
confidence.

Tonight...Steadier rain ends in the evening but lingering low
stratus and some drizzle. This should keep conditions mainly low
MVFR or IFR at least through the evening. Improvement should
follow overnight as northerly winds start to bring in drier
air. Northeast winds around 10 knots shifting to northerly and
diminishing to 5 knots overnight. Moderate confidence.

Saturday...Mainly VFR. Northerly winds 5 to 10 knots shifting
back to east then southeast by late day. Moderate confidence.

Outlook...

Saturday night-Sunday...Sub-VFR conditions probable (50-60
percent chance) at times through the period with chances (40-50
percent) for showers.

Sunday night-Tuesday...VFR conditions expected through Monday.
Sub- VFR conditions with chances for showers return late
Tuesday.

&&

.MARINE...
Winds/seas ramping up through this morning and we
are now expecting a period of Gale conditions today for most of
our ocean zones off the coast of NJ. The exception will be our
northern zone off the coast of Monmouth County. Elsewhere,
widespread Small Craft Advisory conditions. These conditions
will start to improve by late day but still expect it to remain
at Small Craft Advisory levels through Saturday over our ocean
zones, mainly due to seas.

Outlook...

Sunday through Tuesday...Overall, mainly sub-SCA conditions
expected through Monday. Stronger winds may bring SCA conditions
back late Monday into Tuesday.

&&

.TIDES/COASTAL FLOODING...
The new moon occurred Tuesday, May 7th, and this is resulting in
high astronomical tides. As a front settles to our south, an onshore
flow will develop and strengthen some through the end of the week,
peaking today into tonight. While the astronomical tides will be
gradually lowering as we get farther away from the new moon, the
onshore will increase the surge values at least some. With the peak
onshore flow leading up to tonight`s high tide cycle, guidance
continues to indicate the threat for moderate tidal flooding for
portions of Atlantic coastal New Jersey and Delaware, as well as
Delaware Bay with the high tide cycle tonight into early Saturday
morning high tide cycle. With increased confidence of a long
duration of moderate to strong onshore flow through the day today
and water levels/surge values continuing to run high with the latest
high tide cycle last night into early this morning, the Coastal
Flood Warning for tonight`s high tide has been expanded to include
all areas previously covered by the Coastal Flood Watch. The
increasing onshore flow may also result in spotty minor coastal
flooding with the daytime high tide today within the Warning area.

Outside of the Warning area, in adjacent areas of the Atlantic coast
of New Jersey, Delaware Bay, and the tidal Delaware River, another
round of widespread minor coastal flooding is expected with the high
tide cycle tonight into early Saturday morning. Therefore, another
Coastal Flood Advisory has been issued for these areas for the
tonight into early Saturday high tide cycle.

The high tide cycle tonight looks to be the peak of the coastal
flooding impacts area-wide, but additional minor coastal
flooding is forecast with the evening/overnight high tide
Saturday night into early Sunday.

Flooding is not expected at this time for our Maryland zones along
the Chesapeake through Saturday.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Coastal Flood Advisory from 2 AM to 7 AM EDT Saturday for
     PAZ070-071-106.
NJ...Coastal Flood Advisory from midnight tonight to 4 AM EDT
     Saturday for NJZ016.
     Coastal Flood Warning from 8 PM this evening to 4 AM EDT
     Saturday for NJZ020>027.
     Coastal Flood Advisory from 9 PM this evening to 3 AM EDT
     Saturday for NJZ012>014.
     Coastal Flood Advisory from 2 AM to 7 AM EDT Saturday for
     NJZ017>019.
DE...Coastal Flood Advisory from midnight tonight to 4 AM EDT
     Saturday for DEZ001.
     Coastal Flood Warning from 8 PM this evening to 4 AM EDT
     Saturday for DEZ002>004.
MD...None.
MARINE...Small Craft Advisory until 1 PM EDT this afternoon for ANZ430-
     431.
     Small Craft Advisory until 6 PM EDT Saturday for ANZ450-454-
     455.
     Gale Warning until 5 PM EDT this afternoon for ANZ451>453.

&&

$$

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