Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 241943
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
343 PM EDT Sun Mar 24 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 frontal boundary and track northward
into the Canadian Provinces by Friday. High pressure returns late
Friday ahead of a weak disturbance arrives later next weekend.


&&

.NEAR TERM /THROUGH MONDAY/...
Low pressure well offshore and its associated front will continue to move east.
A low developing along the front will move meander well offshore tonight and
Monday but it will not bring any increase in clouds or precip to our region. It
will keep the pressure gradient up a bit for the waters and adjacent land areas
for the near term period. The result of this and a building high to the north
will be a continuation of dry and cool weather to the region. Under clear skies
tonight, lows will drop to the upper 20s to low 30s for most areas. These lows
will be roughly 5 degrees below normal for late March. Winds will be mostly
North to Northeast at 5 to 10 mph with some gusts around 20 mph near the shore
areas.

On Monday, the high pressure to the north will continue to control the weather
for the Middle Atlantic region. Clear skies are expected with perhaps a few
daytime Cu/Sc clouds. After cold morning lows, temperature readings will climb
into the upper 40s/low 50s for most areas. Winds will be mostly Northeast to
East at 5 to 10 mph.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
The short term period will be relatively quiet as our area remains
wedged between two separate low pressure systems. The ridge axis of
the high pressure over southern Canada remains over the Mid-Atlantic
region through most of Tuesday before departing by Tuesday night. To
the east over the Western Atlantic, will be a stalled area of low
pressure whereas to the west across the High Plains, will be an area
of low pressure tracking north of the Great Lakes.

Despite our area remaining under high pressure, some low level
marine stratus will stream in off the western Atlantic on Monday
night persisting into Tuesday. Some drizzle may be possible near
coastal areas due to the combination of northeast winds and moisture
trapped underneath the surface inversion. Elsewhere, expect dry
conditions under mostly cloudy skies. 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.

In terms of temps, expect lows in the 30s Monday night and highs in
the 40s-50s on Tuesday. With more low-level moisture around on
Tuesday night, temps will be a bit warmer than the night prior,
generally in the lower 40s.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
The long term period as whole will become unsettled with several
chances for some precipitation. The cold front to the west will slow
down in forward motion and 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 in the 60-80% range through
Thursday. The low begins to pull away Thursday night as it
nears Nova Scotia, resulting in just some residual showers.

For Friday and Saturday, mostly dry conditions are expected as high
pressure builds in from the south and west. Will have to watch a
warm front that approaches from the west later Saturday associated
with another low pressure system that may impact the area for the
second half of the weekend. This may bring another round of showers
during the Saturday night and Sunday period, but PoPs are only
around 20% at this time.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...

.Tonight... VFR with clear skies expected. Northeast winds 5 to 10 knots. High
confid.

.Monday... VFR with clear skies. Northeast to East winds increasing to 10 to 15
knots with some gusts around 20 knots. High confid.

Outlook...

Monday night...VFR early, likely becoming sub-VFR overnight with
some marine stratus. NE winds around 7-12 kt. Higher gusts up to 20
kt possible at KACY. High confidence.

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

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

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

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

&&

.MARINE...
High pressure to the north over Canada and low pressure well off into the
Atlantic will keep a moderate Northeast flow across the waters tonight and
Monday. Winds have ticked down below Gale levels attm and we have already
cancelled the Gale warning. A low will move up a front well to the east and
deepen tonight and Monday. it should be far enough away to keep winds up,
without reaching Gale levels again. Enhanced seas will continue into Tuesday.

It appears the winds for northern Delaware Bay will remain below SCA while
lower Delaware Bay will continue with SCA gusts and seas (near the mouth) at
least thru Monday. SCA flags have been adjusted accordingly. Fair weather is
expected tonight and Monday.

Outlook...

Monday night through Tuesday...SCA conditions likely to continue. NE
winds around 25-30 kt. Seas of 8-12 feet.

Tuesday night through Wednesday night...SCA conditions likely to
continue due to elevated seas. NE winds around 10-15 kt on Tuesday
night, becoming N-NE winds around 5-10 kt for Wednesday and
Wednesday night. Seas of 5-8 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. NW
winds around 15-25 kt with gusts up to 30 kt. Seas of 4-6 feet.

&&

.TIDES/COASTAL FLOODING...
The coastal low that brought the heavy rain Saturday has
departed to the north and east but a second low has developed
along its cold front and is located off the southeast coast.
This low will strengthen while moving north and then lingering
out over the Atlantic. This 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
Monday. 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 Monday, when
widespread minor flooding begins, but right now the highest tide
appears to be Monday evening`s. Some guidance has moderate flooding
lingering several cycles, but for now have cut off the warning at 2
PM Tuesday. Minor flooding looks likely across the New Jersey side
of the Delaware Bay and the New Castle County portion of the
Delaware side by Monday evening, but as that is still over 24 hours
out, and some uncertainty remains regarding how the event will
transpire, will hold off another cycle before issuing coastal flood
advisories for these areas. Only spotty minor flooding is expected
along the Tidal Delaware river north of Delaware through
Philadelphia up to Trenton. Coastal flooding is not anticipated
along the eastern shore of Maryland.

&&

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

&&

$$

SYNOPSIS...DeSilva/Fitzsimmons
NEAR TERM...PO
SHORT TERM...DeSilva
LONG TERM...DeSilva/Fitzsimmons
AVIATION...DeSilva/PO
MARINE...DeSilva/PO
TIDES/COASTAL FLOODING...RCM


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