251
FXUS61 KPHI 221736
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
136 PM EDT Wed May 22 2024

.SYNOPSIS...
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.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 130 PM, just a few cumulus so far across the region as the
air mass above the boundary layer is rather dry. Terrain
influences initiated a couple of cells not to far north of
Monroe County, PA however this activity quickly weakened as it
moved northeastward. Some additional convection has developed in
central Pennsylvania along the lee-side trough and within a
much more favorable environment. For this update, mainly just
made some upward adjustments to the hourly temperatures this
afternoon inland from the coast as several spots were running a
littler warmer than forecast thus far.

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.

&&

.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 /18Z WEDNESDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...

This afternoon...VFR. A late day isolated shower or thunderstorm
possible in the vicinity of KRDG/KABE. South to southwest winds
around 10 knots. Moderate confidence.

Tonight...VFR for much of the night, however some sub-VFR
conditions with some showers or thunderstorms possible. Greater
chance in the KRDG and KABE areas this evening, then nearly
anywhere overnight. South-southwest winds around 5 knots,
becoming locally light and variable. Low confidence on timing
and coverage of showers/thunder.

Thursday...Some showers and thunderstorms around resulting in a time
of sub-VFR conditions. South to southwest winds 5-10 knots,
becoming west to west-northwest 5 knots or less later at night.
Low confidence in timing and coverage of showers/storms.

Outlook...

Friday...Mostly VFR.

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

&&

.MARINE...
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.

&&

.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