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889
FXUS61 KPHI 241358
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
958 AM EDT Fri May 24 2024

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

.NEAR TERM /THROUGH TONIGHT/...
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Scattered thunderstorms formed ahead of a cold front this
morning across southern New Jersey and Delmarva in response to a
mid- level shortwave moving eastward from Virginia into the
Delmarva. Any storms should diminish in coverage and intensity
by 16Z. The front will drift southward and be south of the area
this afternoon.

Otherwise, surface high pressure over the Great Lakes gradually
builds in from the north and west, bringing in a drier airmass
through this afternoon. Temperatures are expected to warm into
the low to mid 80s for the Philly metro area and points north
where clearer skies are expected. Further south where we will
see the morning precipitation, cloud coverage will slow daytime
heating and likely limit the afternoon high temperatures to the
upper 70s to right around 80.

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 the stalled front 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.
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&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Saturday morning should be fairly quiet as some patchy fog sits
over DelMarVa early. That should lift and mix out with diurnal
heating in the boundary layer. A warm front will push north of
the area with the main forcing for some afternoon showers
occuring late in the day moreso over PA with the best chance for
precip generally over the Lehigh Valley and Poconos. With
guidance trending towards a weaker system the forecast no longer
calls for showers to make it to the shore which then pushes
temps up through the day. Temps are anticipated to again warm
into the mid 80s with low 70s along the shore.

Brief high pressure develops on 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.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
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 /14Z FRIDAY THROUGH TUESDAY/...
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The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...

Rest of today...VFR. Scattered convection in southern Delaware
this morning with ceilings 3-4Kft and locally reduced visibility
to 3SM. Light winds becoming northwest around 5 knots, then
becoming west. A sea/bay breeze will develop along the New
Jersey and 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.

Outlook...

Saturday through Saturday night...VFR during the day, likely
becoming sub-VFR at night. Showers and thunderstorms late in the day
into 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
this morning across the lower Delaware Bay and Delaware coastal
waters. Light and variable winds this morning become SSW around
5-10 kts. Seas remain 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 could setup Saturday morning generally off the
Delaware coastline and over Delaware Bay. Showers and
thunderstorms are anticipated for Monday into Tuesday and could
bring strong to severe winds.

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