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870
FXUS61 KPHI 221346
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
946 AM EDT Wed May 22 2024

.SYNOPSIS...
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High pressure will remain centered to our south and east through
today. A cold front crosses our area Thursday night, then stalls
to our south Friday before lifting back northward Friday night
into Saturday. A cold front moves through Saturday night into
Sunday, then another system moves through Monday into Tuesday.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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As of 940 AM, ample sunshine in progress across the area with a
light south to southwest wind. This is resulting in temperatures
quickly climbing into the low/mid 70s at many locations. The
12z Wallops Island (KWAL) and Upton (KOKX) RAOBs both show a
lot of dry air up through the atmosphere. As heating continues
through the afternoon however, at least some cumulus/mid clouds
should develop. Little was needed to be adjusted with this
update.

Otherwise, weak high pressure will remain offshore. A lee-side
trough will be making its way across central Pennsylvania late
in the day which may focus a few showers and thunderstorms.
Strong daytime heating will provide instability and bring
afternoon temperatures into the mid to upper 80s. MUCAPE values
will increase into the 1000-1500 J/kg range with rather steep
low-level lapse rates. Some limiting factors, though, will be a
lack of deep layer shear in place and the greatest forcing
being displaced well north and west of the area. This said, we
could still see some marginally severe thunderstorms develop
across central PA and shift towards eastern PA late in the day.
These storms would be mainly isolated to scattered in coverage
and have the potential to bring some gusty winds and small hail.
Modest PWAT values of 1.25-1.50" will also support a quick
downpour associated with stronger storms. SPC has outlined a
Marginal Risk (level 1 of 5) for severe weather north and west
of the I-95 corridor.

Some showers and storms could persist into the overnight period
as well with the trough lingering through early Thursday
morning. Storms will lose steam after sunset with the loss of
daytime heating, though an isolated thunderstorm can`t be ruled
out overnight. Lows in the low to mid 60s.
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&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
On Thursday, a pre-frontal trough will be in place across the
Mid Atlantic region, while a cold front will be approaching from
the west. A couple of rounds of showers and thunderstorms will
be possible Thursday into Thursday evening. As daytime
instability begins to develop through the day, showers and
thunderstorms could begin to develop as a short wave moves into
the area and interacts with the surface trough. CAPE values
increase to 1000-2000+ J/kg, and shear values will reach 25-35
knots, even though mid-level winds are fairly weak; generally
30-40 knots or less. Some storms could become strong to severe,
with hail or damaging winds possible. While the main threat for
severe storms will be during the day and into the evening hours,
there will remain the potential for showers and thunderstorms
into the overnight hours as the cold front slowly continues to
move across the area. PW values reach 1.25-1.50+ inches, so
there will be periods of heavy rainfall with any showers and
thunderstorms.

The cold front is expected to push to the south of the area
Friday and stall there and likely dissipate, before a backdoor
front may sag southward into the area from the north. PW values
drop through the day Friday into Friday night, but remain
elevated across southern New Jersey, Delaware, and eastern
Maryland, especially early in the day Friday. So these areas
have the best chance of showers Friday into Friday night.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Unsettled weather is expected for the weekend into early next
week as multiple frontal boundaries and low pressure systems
will move across or near the area. The weekend does not look
like a wash out, and may be dry for most areas. Any shower
activity will likely be focused around a couple of short
wave/vorticity impulses as any fronts moving into the area over
the weekend look to be fairly weak and only a modest increase in
PW values is expected. One is expected later Saturday into
Saturday evening, and the other later Sunday into Sunday night.

Moving into Monday and Tuesday, precipitation chances will be
higher as a stronger front and is expected to move into the area
while additonal short wave/vorticity impulses move across the
area and an increase in PW values is expected.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
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The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...

Today...VFR. A late day isolated shower or thunderstorm
possible in the vicinity of KRDG/KABE. Light and variable winds,
becoming south-southwest 5-10 knots. Moderate confidence.

Tonight...Areas of sub-VFR conditions with some showers or
thunderstorms possible, mostly north and west of KPHL.
Otherwise, VFR conditions. South-southwest winds around 5 knots,
becoming locally light and variable. Moderate confidence.

Outlook...

Thursday...Sub-VFR conditions possible with a chance of showers
and thunderstorms.

Friday...Mostly VFR conditions.

Saturday and Sunday...Generally VFR conditions, however there is
a chance of lower conditions at times with any showers.
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&&

.MARINE...
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No marine headlines through tonight.

Outlook...

Thursday through Sunday...Conditions expected to remain below
Small Craft Advisory levels.

Rip Currents...

Today, for the Monmouth County, NJ beaches and the Delaware
Beaches, there is a LOW risk for rip currents as wind direction
will be more shore-parallel with only 2 to 3 foot breaking
waves and an 8 second period. A more onshore component of the
wind will exist for Ocean/Atlantic/Cape May beaches, where a
MODERATE risk for the development of dangerous rip currents
remains.

For Thursday, the wind direction goes more southwesterly.
Breaking waves will only be around 2 feet with a 6 to 8 second
period. All beaches will have a LOW risk for the development of
dangerous rip currents.
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&&

.TIDES/COASTAL FLOODING...
Astronomical tides will be elevated this week with a Full Moon
on Thursday, May 23. Spotty minor coastal flooding will be
possible, especially for the back bays, around the times of the
evening high tide cycle, which will be the higher of the two
tide cycles, going into the end of this week.

&&

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

&&

$$

SYNOPSIS...Gorse/Robertson
NEAR TERM...Gorse/MJL
SHORT TERM...Robertson
LONG TERM...Robertson
AVIATION...Gorse/MJL/Robertson
MARINE...MJL/Robertson
TIDES/COASTAL FLOODING...PHI