NWS Philadelphia/Mount Holly wrote its last area forecast discussion before the first event at May 28, 2:55 PM EST, 5 minutes earlier.
Area forecast discussion, May 28, 2:55 PM EST, 5 minutes before
Area Forecast Discussion
National Weather Service Mount Holly NJ
355 PM EDT Sun May 28 2023
.SYNOPSIS...
High pressure over the Northeast and Great Lakes regions will
weaken tonight and drift out to sea. Meanwhile, low pressure
over the Southeast will drift towards the Mid-Atlantic through
mid-week. High pressure then returns for the end of the week. A
cold front may affect the region next weekend.
&&
.NEAR TERM /THROUGH MONDAY/...
High pressure centered over Hudson Bay will continue to sag to the
south and east tonight through Monday, and will be over the Canadian
Maritimes by Monday afternoon. Meanwhile, closed H5 low over the
Tennessee Valley will slowly drift to the east and will be over the
Carolina coast by Monday afternoon. Surface low associated with this
system will meander over the Mid-Atlantic during this time as well.
Bands of light rain showers will lift to the north and will mainly
impact Delmarva and extreme southeast New Jersey this afternoon, but
will wind down into this evening. Onshore flow will result in patchy
fog developing along the southeast New Jersey coast and Delmarva
late tonight and into Monday morning.
For Monday, bands of rain showers will continue to lift to the north
into the far southern areas. There should be enough upper level
instability due to shortwave energy to result in a chance for a
rumble of thunder or two in Delmarva and possibly into extreme
southern New Jersey Monday afternoon.
As high pressure to the north builds to the south and east, and as
low pressure over the Mid-Atlantic drifts a bit farther to the
north, a tightening northeast pressure gradient will develop,
mainly over northern New Jersey. Winds will be light and variable,
though with an onshore component, and then northeast winds increase
to 15 to 20 mph with 25 to 30 mph gusts, mainly along the coasts, as
well as across northern New Jersey and down the I-95 corridor by
Monday afternoon.
Lows tonight will be in the 50s. Highs on Monday will be in the
lower 80s across portions of southeast Pennsylvania and northern New
Jersey, and otherwise in the upper 70s to low 80s for most other
inland areas. Highs along the coasts will be in the upper 60s to low
70s owed to onshore flow and the colder ocean temperatures.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
The short term forecast period looks to be dominated by a rather
stagnant weather pattern, particularly at the surface. A high
amplitude upper level ridge will promote continued strong surface
high pressure, centered offshore to the east of the region.
Underneath the upper level ridge, a cutoff upper level low with an
associated surface low will continue to be centered just south of
the region. The continued presence of the high pressure will prevent
the low from advancing very far north through this period.
As a result, it is a tale of two forecasts, depending on your
location relative to the low. Areas south and east of the I-95 urban
corridor, which are closer to the low, will see continued cloudy
conditions with chances for showers (generally 30-50%). High
temperatures will also be cooler in this area, upper 60s to near 70
on Tuesday, then low 70s on Wednesday. North and west of the urban
corridor, conditions are expected to be dry through Wednesday, with
mostly clear skies. High temperatures in this area are expected to
be in the mid to upper 70s each day. The I-95 urban corridor itself
will generally be straddling the edge of the influence of the low.
As a result, showers cannot be completely ruled out in this region
(PoPs generally 15-25% through Wednesday).
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
It will take until midweek, but the last remnants of the upper low
from the SE/Mid-Atlantic will be moving across the area Wed night
before finally dissipating. This first period (Wed night) will have
chance pops for Delmarva/srn NJ and slight chance pops further NW
including the Delaware Valley. After that, a couple (more) dry days
for the region as both a surface and upper ridge develop over the
region. This ridge doen't last long since a trough deepens over New
England and the Canadian maritime provinces next weekend. The
operational models differ with the details, but a cold front should
push through and probably bring chances for some showers.
Temperatures will be above normal Thu with mostly mid 80s inland and
upper 70s/low 80s near the shore and Delmarva. Under a decent sunny
day Fri, readings will climb further, topping out in the upper
80s/low 90s inland and low/mid 80s for the shore. After that,
provided that the cold front crosses the area, readings should tick
back closer to normal by late weekend.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Rest of this afternoon (through 00Z)...VFR/SCT-BKN250. E-SE winds 5
to 10 kt. High confidence.
Tonight (00Z through 12Z)...VFR for most terminals, through at least
MVFR conditions in fog and stratus will develop at KMIV/KACY after
09Z. LGT/VRB winds. Moderate confidence.
Monday (12Z through 00Z)...Any sub-VFR conditions at KMIV/KACY will
lift in the morning. VFR otherwise. Light SHRA possible at KMIV/KACY
in the afternoon. E-NE winds 5 to 10 kt, becoming E 15 to 20 kt with
gusts up to 20 kt after 18Z. Moderate confidence.
Outlook...
Monday night through Wednesday...VFR conditions will likely persist
for most of our TAF sites, though showers will try to advance
northward at times, possibly reaching as far as KPHL or so. KACY and
KMIV could possibly have occasional MVFR ceilings, but that would
probably be the reasonable worst case. Lower conditions with MVFR
VSBY in showers will be possible closer to Delaware Bay on
southward. Winds will be steady from the ENE, generally 10 to 15 kt
but a bit higher on Tuesday, with some gusts 20 to 25 kt possible
near the coast. Moderate confidence.
Thursday/Friday...VFR expected most of the time.
&&
.MARINE...
Low pressure continues to meander over the Carolina coast/Mid-
Atlantic through Monday. Seas at 44009 remain around 5 ft and will
hover around 5 ft into this evening. Will extend the Small Craft
Advisory until 10 pm, but will also remove ANZ453 from the SCA.
Conditions sub-SCA criteria with an onshore flow into Monday
morning. Monday afternoon, NE winds increase to 15 to 20 kt with
gusts up to 25 kt for northern NJ ocean waters, and around 15 kt
with gusts to 20 kt for southern NJ and DE ocean waters. Seas build
to 5 to 6 ft over northern NJ ocean waters, and seas will build to 3
to 4 ft elsewhere. Will hoist a SCA for ANZ450-451 starting at 18Z.
Outlook...
Monday night...Small Craft Advisory continues for coastal waters
north of Little Egg Inlet. Northeast winds 15 to 20 kts with gusts
to around 25 kts. Seas of 4 to 6 feet. South of the SCA, northeast
winds around 15 kts with seas of 3 to 5 feet. Showers possible south
of Little Egg Inlet (20-40% chance north of Cape May, 40-60% chance
south of Cape May).
Tuesday...SCA conditions likely continue and expand to all coastal
ocean waters as seas increase to 4 to 6 feet. Northeast winds 15 to
20 knots, with gusts around 25 kts. Winds decrease to 10 to 15 kts
and seas begin to decrease to 3 to 5 feet Tuesday night. 15-35%
chance for showers north of Little Egg Inlet, 35-55% chance south.
Wednesday...Marine headlines unlikely. Seas decrease to 2 to 4 feet.
Northeast winds around 10 to 15 knots. 25-45% chance for showers,
with increasing showers further south.
Rip Currents...
A MODERATE risk for the development of dangerous rip currents continues
for both the New Jersey and Delaware Beaches into Memorial Day. An
onshore wind pattern will continue over the next few days with
the exception of weak southerly flow developing along the central
and northern NJ shore for a few hours Monday. Additionally, seas
remain elevated in the 4 to 6 ft range, and the dominant swell is
a easterly/southeasterly swell with a period of approximately 8
seconds. NWPS rip probabilities are surprisingly high, but chose
to continue with the moderate risk as the pattern won't be significantly
different from today and observations today support a moderate risk.
Additionally, our local program supports a moderate risk.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory from 2 PM Monday to 6 AM EDT Tuesday for
ANZ450-451.
Small Craft Advisory until 10 PM EDT this evening for ANZ454-
455.
&&
SYNOPSIS...Staff
NEAR TERM...MPS
SHORT TERM...AKL
LONG TERM...OHara
AVIATION...AKL/MPS
MARINE...AKL/MPS