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000
FXUS61 KPHI 250056
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
856 PM EDT Fri Jun 24 2022

.SYNOPSIS...
High pressure will be nearly overhead tonight before shifting
offshore during the weekend. A cold front will then cross the
region Monday. High pressure will return Tuesday and likely last
through the remainder of next week.

&&

.NEAR TERM /THROUGH SATURDAY/...
Quiet weather commences as we begin a warm up into this
weekend. High pressure will build into the region through
Saturday as a closed 500 mb low slowly lifts to our north and
east south of the Canadian Maritime Provinces. A mid-level ridge
will continue to build into the Northeast behind this low.
Highs will nudge upward with weak southwesterly flow and added
subsidence beneath the building surface high.

Only a few minor adjustments were needed to the ongoing
forecast. We will clear out tonight with radiational cooling
taking place. Trended temperatures a little cooler over the
usual favorable radiational cooling location over the Lehigh
Valley and Poconos and also over the Pine Barrens. Some patchy
fog is also possible again tonight, though less extensive and
less stratus than Friday morning given the slightly drier air
and no rainfall to add surface moisture to the airmass. Winds
will continue to remain light and variable.

We continue to warm into Saturday as the center of the surface
high shifts offshore and stronger return flow takes over from
the southwest. Highs should reach into the upper 80s with a few
90- degree readings in the urban corridor. Some additional fair
weather cumulus once again through the late morning and
afternoon.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
The short term starts off Saturday night with a building ridge
axis over our region, with an upper level low south of Nova
Scotia, an upper level high over the southern Mississippi
Valley, and another closed low over south-central Canada. At the
surface, high pressure will be offshore, with a fairly light
south to southwest wind flow over the region. Despite this, the
flow will not yet be strong enough to bring in higher dew
points, so it will remain relatively comfortable for this time
of year, with temps fairly close to normal. Radiational cooling
and lingering moisture from the rain the other day may still
result in some patchy fog, but it should be quite limited
compared to Friday morning.

The high shifts further offshore on Sunday, but the ridge axis
looks to have peaked Saturday night, with heights starting to
fall as the closed low to the northwest starts sending a strong
shortwave our way. This will limit additional heating on Sunday,
with temps only expected to warm slightly compared to
Saturday. Dew points also look likely to remain mostly in the
low-mid 60s given limited return moisture, so while it will be
rather hot, heat indices will be fairly close to air temps, so
no heat advisories expected. Highs will top in the low 90s for
the urban corridor, with upper 80s in the cooler spots along the
coast and in the higher terrain.

As the upper trough continues progressing eastward to our north,
shortwave will continue moving toward us. There are hints in the
guidance that there may be enough of an onshore flow Sunday
night into Monday to bring some more stable marine air into our
area ahead of the front`s passage on Monday. Guidance also keeps
most of the strong forcing to our north, with another piece
staying notably south. Also, while lows will be a bit milder
Sunday night with increasing clouds, highs will struggle to rise
much above 80 thanks to plentiful cloud cover. Therefore, while
widespread showers look to be a near- slam dunk on Monday with
the front, the risk of severe weather or flooding does not look
significant at this point.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Overview...

A cold front will exit the region Monday night and high pressure
will build into the region for the remainder of the week.
Temperatures will start out on the cooler side Tuesday, but warm
notably by Friday.

Details...

Guidance overall is in pretty good agreement regarding a
relatively quiet period for the bulk of next week after the cold
front passes Monday. GFS/GGEM/ECMWF all have precip clearing out
Monday evening, with the front settling to our south in southern
Virginia and the Carolinas...just far enough away to keep
unsettled weather at bay for our region. Canadian high pressure
building in for Tuesday will bring a notably drier air mass...
dew points approaching 70 on Monday will be 15 degrees lower on
Tuesday. Unlike with the last cooler, drier air mass which built
in last weekend, this one doesn`t appear to be accompanied by
particularly gusty winds, with a notably weaker pressure
gradient. Temps will be similar to Monday otherwise, with high
70s to low 80s common, with plenty of sun.

After that, high pressure gradually shifts eastward toward the
Atlantic, with a shortwave passing Wednesday with little if any
impact, then the ridge building more strongly overhead Thursday
into Friday. This will allow temps to rise back above normal by
week`s end, but the air mass will take longer to moisten up,
with dew points creeping slowly back into the 60s by Thursday
and Friday, but nothing excessive. Without any boundaries to
focus on, precipitation should be minimal if not completely
non-existent, with clear to partly cloudy skies predominating.

&&

.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Tonight..Mostly VFR though some patchy dense fog may lead to a
few restrictions. Winds light and variable. Moderate confidence.

Saturday... VFR. Light southwest winds from 5 to 10 knots. High
confidence.

Outlook...

Saturday night...VFR with light southwest wind 5-10 knots. No
precipitation. Very slight chance of fog. Moderate-high
confidence.

Sunday...VFR. Southwest winds around 5-10 kts with gusts up to
15 kts. High confidence.

Sunday night...VFR. Cigs thicken and lower, but showers stay
west most likely. Southwest winds 5-10 kts. Moderate-high
confidence.

Monday...Intervals of MVFR and possibly IFR with showers and
possible thunderstorms crossing the terminals, especially late
morning thru mid-late afternoon. Winds SW shifting to NW 5-10
kts with gusts to 15 kts. Low-moderate confidence.

Monday night...Conditions improving back to solid VFR behind a
cold front with winds shifting to NW 5-10 kts. Moderate-high
confidence.

Tuesday... VFR. Northwest winds 5 to 10 kts. High confidence.

Wednesday...VFR. Winds shifting to SW 5-10 kts. High confidence.

&&

.MARINE...
Sub-advisory conditions expected with southwest winds from 5 to
10 knots and gusts to 15 knots. Seas from 2 to 4 feet.

Outlook...

Sunday...Sub-SCA conditions expected. South to southwest winds
slowly increasing in speed to 10-15 kts by the late afternoon.
Gusts up to 20 kts possible. Seas 2 to 4 ft.

Monday...Mostly sub-SCA. Southwest winds persisting around 10
to 15 kts with gusts of 15 to 20 kts expected. Seas 2 to 4 ft.
Thunderstorms possible mainly in the afternoon into early
evening which may cause higher winds and waves.

Tuesday... Mostly sub-SCA. Winds out of the north 10 to 15 kts.
Gusts up to 20 kts. Seas 2 to 4 ft.

Wednesday...Sub-SCA conditions likely. Winds shifting to
south 10-15 kts with gusts up to 20 kts. Seas 2 to 4 ft.

Rip Currents...

A southwest wind 5 to 10 MPH on Saturday morning should become south
around 10 MPH on Saturday afternoon. Breaking waves will likely be
around 2 feet with a medium period easterly swell. There should
result in a MODERATE risk for the development of dangerous rip
currents for the NJ shore with a LOW risk for the Delaware Beaches.

Similar conditions are forecast for Sunday so we are forecasting the
risk to remain MODERATE for New Jersey beaches and LOW for Delaware.

&&

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

&&

$$
Synopsis...RCM
Near Term...Davis
Short Term...RCM
Long Term...RCM
Aviation...Davis/RCM
Marine...Davis/RCM