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743
FXUS61 KPHI 241723
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
123 PM EDT Fri May 24 2024

.SYNOPSIS...
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A cold front across the central Delmarva and Cape May New
Jersey early this afternoon will drift southward and stall just
to our south late this afternoon. It will lift back north
tonight as a warm front. Another stronger system will impact the
area on Monday into Tuesday.
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&&

.NEAR TERM /THROUGH SATURDAY/...
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Convection across southern Delaware and nearby Maryland
continues this afternoon in response to a mid- level shortwave
moving eastward across the Delmarva. Most convection should end
or move south of the area by 19Z.

Otherwise, surface high pressure over the Great Lakes gradually
builds in from the north and west, bringing in a drier airmass
through this afternoon. Tranquil weather will continue tonight
with clear skies and light winds initially. We should be able
to radiate pretty well leading to some patchy fog development
over Delmarva and southern New Jersey. However, clouds will
increase from south to north later in the night as a stalled
front toour south begins to lift back north across the area.
This should limit the amount of cooling late, so expecting lows
in the mid 50s to lower 60s with mid 60s around Philadelphia.

Other than patchy morning fog over the Delamrva, Saturday
morning should be fairly tranquil. A warm front will push north
of the area with the main forcing for some afternoon showers
occuring late in the day over the Lehigh Valley and Poconos. The
showers will progress eastward to the Delaware Valley by
Saturday evening. Temperatures are anticipated to rise into the
mid 80s with low 70s along the shore.
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&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
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Brief high pressure develops Sunday with the front stalled to
the north of the region and it should be another pleasant day
across the region with sunny skies and fair weather CU
developing. Highs Sunday should also push into the mid 80s with
70s along the shore. Expect lows each night to fall into the 50s
to low 60s.
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&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
The work week begins with a more unsettled pattern. Starting
Monday an upper level system will push a cold front through the
region. With warm air advection initially and strong PVA, there
will be ample lift associated with the system tapping into a
surge of PWAT from both the Gulf and the Carolinas. This leads
to widespread convection across the region and EL`s should be
sufficient to support thunderstorms. While CIPS guidance has
started to trend slightly down on the severe threat yesterday,
the 00z GEFS showed a significant increase back to a 10-15%
chance of severe weather on Monday. Bulk shear vectors point
towards 35-40kts with mid level lapse rates in the 6 degC/km.
This should provide enough forcing for some stronger storms to
become severe. WPC upgraded the Marginal from yesterday to a
Slight risk for portions of the I95 corridor and PA. Given that
SPORT LIS Soil Moisture data show dry conditions in the 10-40cm
depth range, anticipate that any flooding will most likely be
over the impervious surfaces of the more urban area rather than
over more rural areas. Given the increasing confidence in at
least heavy rain, the forecast was updated to include specific
mention of heavy rainfall for any locations where the precip
chances were higher than 55%.

After the cold front passes, unsettled weather continues to be
the theme thanks to several waves/impulses aloft passing through
the week. Temps for the work week should be fairly seasonable
with highs in the 70s through Wednesday, before falling back
into the 60s by Thursday.

&&

.AVIATION /17Z FRIDAY THROUGH TUESDAY/...
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The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...

This afternoon...VFR. Scattered showers in southern Delaware
early this afternoon. Light winds becoming northwest around 5
knots, then becoming west. A sea/bay breeze will develop along
the New Jersey and northern Delaware coasts in the afternoon.

Tonight...Clear skies and calm winds. Fog may form in southern
New Jersey and Delmarva after 06Z with visibility 3-5SM.

Saturday...VFR. Widely scattered showers and thunderstorms late
in the day in the Poconos and Lehigh Valley.


Outlook...

Saturday night...VFR. Widely scattered showers and thunderstorms
in the evening.

Sunday...VFR. No significant weather expected.

Sunday night through Tuesday...Sub-VFR conditions probable with a
chance of showers and strong thunderstorms especially on Monday
into Monday night.
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&&

.MARINE...
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The conditions are expected to remain below Small Craft Advisory
criteria through tonight. Scattered showers and thunderstorms
Delaware coastal waters this afternoon. Light and variable
winds becoming SSW around 5-10 kts. Seas around 2 feet.

Outlook...

Saturday through Tuesday...No marine headlines expected. Winds
will occasionally gust up to 15-20 kt with seas around 2-4 feet.
Marine fog is possible Saturday morning off the Delaware
coastline and over Delaware Bay. Showers and thunderstorms are
anticipated for Monday into Tuesday.

Rip Currents...

For today, winds will once again be out of the S to SW at 5 to
10 mph with breaking waves of 1 to 2 feet. There is a LOW risk
for the development of dangerous rip currents at NJ and DE
beaches. Although there is a slight chance for showers,
thunderstorms are not expected.

The LOW risk for the development of dangerous rip currents is
expected to continue for Saturday.
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&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.

&&

$$

SYNOPSIS...Deal/DeSilva/Franklin
NEAR TERM...Franklin/MJL
SHORT TERM...Deal/DeSilva
LONG TERM...Deal/DeSilva
AVIATION...Deal/Franklin/MJL
MARINE...Deal/Franklin/MJL