Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 251028
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
628 AM EDT Mon Mar 25 2024

.SYNOPSIS...
High pressure over southeast Canada will extend into the Mid-
Atlantic region through Tuesday. An area of low pressure will track
northwest of the area on Wednesday with a trailing cold front that
will approach from the Midwest on Thursday. A coastal low may
potentially develop along this front and track northward into the
Canadian Provinces by Friday. High pressure returns late Friday
ahead of a weak disturbance arriving later next weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
The weather remains quiet early this morning under a mainly
clear sky with light winds. An area of high pressure remains
centered to our north over Quebec while an ocean storm continues
to sit and spin to our east several hundred miles out into the
Atlantic. This low will meander around out there through the day
today. As this occurs, the pressure gradient should tighten
up some to its northwest into our area as we head through the
morning. This combined with the strong high pressure to our
north will result in dry and cool weather, however there will be
an uptick in the winds today especially closer to the coast.
Otherwise, a mostly clear sky is expected for today with highs
climbing into the upper 40s/low 50s for most areas. The
increasing northeast wind however will also become gusty at
times especially closer to the coast. Wind gusts along the coast
look to be about 30-35 mph.

By tonight, the continuing northeast winds look to moisten the lower
levels with forecast models still indicating a low stratus deck to
form near the coast and advect inland bringing the area mostly
cloudy skies by Tuesday morning. This will also result in it being a
milder night with lows mostly in the low to mid 30s, except near 40
along the coast and over southern Delaware and in the upper 20s over
the southern Poconos.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
The marine stratus deck looks to persist over the area much of
Tuesday making for a mostly cloudy day. We also can`t rule out some
drizzle near coastal areas due to the combination of northeast winds
and moisture trapped underneath the surface inversion. Elsewhere,
expect dry conditions under the mostly cloudy skies. High
temperatures looks to be similar to Monday, generally in the upper
40s to low 50s.

Moving into Tuesday night, the cold front associated with low
pressure tracking north of the Great Lakes will begin to approach.
With better forcing over our northern and western areas, some rain
showers are possible. Overall, should remain pretty light in nature
as frontal boundary will be weakening as it approaches.

The cold front to the west will slow down in forward motion and
continue to weaken as it approaches; coming to a crawl near our
region on Wednesday. As the front potentially stalls, the majority
of deterministic and ensemble long range guidance depicts a coastal
trough and an eventual coastal low forming along the boundary on
Thursday. This will bring another round of rain to the region, with
PoPs holding steady mostly in the 60-80% range Wednesday night
through Thursday (highest near the coast and lowest over N/W area of
the County Warning Area). We will have to closely watch this system
closely as it could once again bring some heavy rainfall to the
area. Currently the majority of the deterministic model guidance has
the heaviest rain falling near or off the coast but if this shifts
N/W as some of the GEFS ensemble members suggest, it could once
again bring significant rainfall towards or into the I-95 corridor.
Confidence on these details though is low at this time.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
The coastal low described in the short term section could linger
Thursday night perhaps even into early Friday depending on its
strength, track, and speed. Also worth noting, a change to some
wintry precipitation will be possible across the southern Poconos on
the backside of the system before it departs. Thereafter, high
pressure should eventually build back into the area by late
Friday with seasonable temperatures. This high doesn`t look to
be particularly strong over the area and by next weekend an
east/west oriented frontal boundary looks to set up near the mid
Atlantic. While the weekend doesn`t look to be a washout at
this time some disturbances moving along this boundary could
bring some showers from time to time.

&&

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

Through today...VFR. Northeasterly winds increasing through this
morning to 8-15 knots with gusts 20-25 knots, strongest winds
at KMIV and KACY. High confidence.

Tonight...VFR early, becoming sub-VFR overnight with marine
stratus developing and advecting inland...possibly not reaching
RDG and ABE until around 10-12z Tuesday. NE winds 7-12 kt.
Higher gusts up to 20 kt possible at KACY. Moderate confidence.


Outlook...

Tuesday through Tuesday night...Mainly sub-VFR. Drizzle
possible near KACY during the day, with some showers developing
at night. NE-E winds around 10 kt during the day, becoming 5 kt
or less at night. Moderate confidence.

Wednesday through Wednesday night...Sub-VFR with periods of
rain. SE-S winds around 5-10 kt during the day, becoming NW-N
winds around 5 kt late at night. Low confidence.

Thursday through Thursday night...Sub-VFR with periods of rain.
NW-N winds around 10-15 kt with gusts up to 20 kt. Low
confidence.

Friday...VFR or becoming VFR with clearing skies. NW winds
around 15-20 kt with gusts up to 30 kt. Moderate confidence.

&&

.MARINE...
Low pressure well offshore will meander out there through today.
It`s close enough to keep winds up, however they should remain
below Gale-force. Enhanced seas will continue.

It appears the winds for the upper Delaware Bay will remain
below Small Craft Advisory criteria while lower Delaware Bay
will continue with advisory level gusts and seas (near the
mouth) at least through the day today.

For the tonight through Tuesday period, the winds will
gradually subside however the seas will remain elevated so we`ve
extended the Small Craft Advisory through the day Tuesday.


Outlook...

Tuesday night through Wednesday...SCA conditions likely to
continue due to elevated seas generally 5 to 8 feet.

Thursday...Marginal SCA conditions. NW-N winds around 10-20 kt. Seas
of 4-5 feet.

Thursday night through Friday...SCA conditions likely to return
with even the potential for Gale force winds. NW winds around
15-25 kt with gusts 30 to 35 kt. Seas of 4-6 feet.

&&

.TIDES/COASTAL FLOODING...
A low pressure system lingering well off the coast will result
in an extended duration of long period swells and rough surf
impacting the Atlantic coast. Surge values of 2-3 feet are
currently forecast by today. This will result in widespread
MODERATE flooding along the oceanfront and Delaware side of the
Delaware Bay. Thus, we have issued Coastal Flood Warnings
starting early this morning, when widespread MINOR flooding
begins, but right now the highest tide appears to be this
evening`s. Some guidance has MODERATE flooding lingering
several cycles, but for now have cut off the warning at 2 PM
Tuesday.

Widespread MINOR flooding looks likely across the Cumberland
County, NJ side of the Delaware Bay with this morning`s high
tide and the Salem County, NJ and New Castle County, DE shores
of the upper bay by this evening`s. Therefore, Coastal Flood
Advisories were issued beginning early this morning and later
this evening, respectively and both continue through mid-
afternoon Tuesday as well with widespread MINOR flooding
expected with each successive cycle. Spotty MODERATE flooding
is also possible in these areas with the highest high tides this
evening and Tuesday morning.

Coastal flooding is not anticipated along the tidal Delaware
River or the eastern shore of Maryland through the daytime high
tides Tuesday. Spotty MINOR tidal flooding may be possible
beyond this time but confidence remains low overall.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...Coastal Flood Advisory from 11 PM this evening to 3 PM EDT
     Tuesday for NJZ016.
     Coastal Flood Warning until 2 PM EDT Tuesday for NJZ020-
     022>027.
     Coastal Flood Warning from 6 PM this evening to 2 PM EDT
     Tuesday for NJZ012>014.
     Coastal Flood Advisory until 2 PM EDT Tuesday for NJZ021.
DE...Coastal Flood Advisory from 11 PM this evening to 3 PM EDT
     Tuesday for DEZ001.
     Coastal Flood Warning until 2 PM EDT Tuesday for DEZ002>004.
MD...None.
MARINE...Small Craft Advisory until 7 PM EDT this evening for ANZ431.
     Small Craft Advisory until 6 PM EDT Tuesday for ANZ450>455.

&&

$$

SYNOPSIS...DeSilva/Fitzsimmons
NEAR TERM...Fitzsimmons/Gorse/OHara
SHORT TERM...Fitzsimmons
LONG TERM...Fitzsimmons
AVIATION...Fitzsimmons
MARINE...Gorse
TIDES/COASTAL FLOODING...


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