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000
FXUS61 KPHI 191739
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
139 PM EDT Fri Apr 19 2024

.SYNOPSIS...
A cold front moves across the region tonight, then continues to
track south and east of the region through the weekend. High
pressure builds in from the west and will be over the area into the
middle of next week. A cold front passes through on Wednesday,
followed by high pressure to close out the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Forecast is relatively on track this afternoon. Low clouds have
kept things a bit cooler, so nudged down hourly temperatures a
few degrees. A quite cool spring day overall. Previous full
discussion follows...

In the wake of a backdoor cold front, high pressure will remain
centered near Nova Scotia and the Gulf of Maine with ridging
extending southward across the Mid-Atlantic for Friday. However,
an area of low pressure cutting across the Great Lakes will send
a cold front across the Appalachians tonight, as that high
pressure and ridging quickly gives way. A steep inversion with
low clouds trapped across our region along with chilly northeast
flow in the boundary layer will result in another generally
gloomy day, though as the ridge shifts east, winds will turn
more southeasterly, allowing for a little milder air to push in.
Additionally, while the day will start off chilly with
temperatures in the low to mid 40s for most spots, cloud bases
will be noticeably higher along with an absence of any drizzle,
compared to the damp conditions Thursday morning. The exception
will be right around the Pocono Plateau and some of the adjacent
ridgetops into NW NJ early this morning. Highs will reach
farther into the 50s, with even some low 60s possible from
around Philadelphia southward into the Delmarva.

This afternoon as a weak pre-frontal shortwave trough and some
isentropic lift combine, scattered light showers will begin to
spread eastward across Pennsylvania, with isolated showers
possibly reaching the I-95 corridor toward sunset. Scattered
showers will then spread eastward across the coastal plain
toward midnight, then gradually taper off from west to east,
with just some lingering activity along the coast after sunrise
on Saturday morning. Rainfall amounts will only be around a
tenth of an inch. Some patchy fog may develop at times
overnight, but dense fog is not expected.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
Dry conditions for the local area for the Short Term period. The
cold front continues to track to the south and east of the Mid-
Atlantic through the weekend, but the tail end of the front will
extend back through the Mid-Atlantic and Gulf Coast. High pressure
builds over the region for the weekend and start of the new work
week. Low pressure develops on that old front and will begin to push
the front back north as a warm front, but the system will stay well
south of the region, and any rainfall on Sunday will stay south of
Delaware.

Chilly temperatures in place. Highs will be in the upper 50s to
around 60 on Sunday, and then in the low to mid 60s on Monday. Lows
generally in the 30s to low 40s. There may be some patchy frost in
the southern Poconos late Saturday night.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
Elongated high pressure along the East Coast slides out to sea
Tuesday through Tuesday night. Low pressure approaching from the
west will drag a cold front through the region Tuesday night through
Wednesday, bringing at least a chance for area-wide showers across
the region during that time, though will also carry likely PoPs for
areas north and west of the I-95 corridor.

Temperatures moderate to near normal levels ahead of this front with
highs generally in the mid and upper 60s. Behind the passage of the
cold front, cold air advection will be underway, and highs drop back
into the upper 50s and low 60s Thursday before rebounding on Friday.

One thing to look out for is the potential for frost development
late Monday night and Tuesday morning, mainly for the southern
Poconos and far northwest New Jersey. Lows will drop into the low to
mid 30s with light winds and Max RH values around 70 percent. Will
carry patchy frost for those areas.

Lows Wednesday night and Thursday night will drop into the 30s for
most areas. It is too soon to determine if conditions will promote
frost development.

&&

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

Rest of Today...MVFR CIGs with no visibility restrictions
expected. Winds out of the southeast around 5-10 kt. High
confidence.

Tonight...Ceilings lowering into the IFR range for the most
part (the exception being KABE/KRDG who are right on the
MVFR/IFR border). Rain will generally be light for areas that do
see showers, so not expecting much in terms of visibility
restrictions. Outside of KACY, visibility of 5 miles or less has
a probability of 20-40% after midnight, so can`t rule it out
entirely. Have higher confidence in reduced visibility at KACY.
This in part due to the potential for some marine fog coming
onshore in addition to the scattered showers. Winds out of the
south/southeast around 5 kt, becoming west/northwesterly late
tonight once the cold front moves through. Moderate confidence
overall.

Saturday...MVFR CIGs to start, lifting to VFR by the late
morning as skies clear out. West/northwest winds around 10 kt
with some spots seeing gusts near 20 kt. Moderate confidence
overall.

Outlook...

Saturday night through Wednesday...VFR conditions until Tuesday
night, then possible sub-VFR conditions in SHRA Tuesday night and
Wednesday.

&&

.MARINE...
A Small Craft Advisory is in effect currently for all the ocean
zones due to elevated seas from stronger NE winds on Thursday
and Thursday night. SCA conditions are expected on the ocean
waters through late tonight as seas around 6-7 ft this morning
gradually lower toward 5 ft into tonight. Otherwise, winds are
gradually easing this morning, ENE 10-15 kt, tending SE 5-10 kt
tonight.


Outlook...

Saturday night through Wednesday...Tranquil conditions for most of
the new week, then VSBY restrictions in showers Tuesday night and
Wednesday. Sub-SCA conditions Saturday night through Tuesday
night, and then potential SCA conditions Wednesday.
&&

.TIDES/COASTAL FLOODING...
Spotty minor tidal flooding was observed within some of the
back bay communities of Ocean County, NJ and Sussex County, DE this
morning. Some minor tidal flooding remains possible through
tomorrow morning around high tide within Barnegat Bay. Tidal
flooding is not expected oceanside for any communities.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 6 AM EDT Saturday for ANZ450>455.

&&

$$

SYNOPSIS...MPS
NEAR TERM...Dodd/Hoeflich
SHORT TERM...MPS
LONG TERM...MPS
AVIATION...Dodd/Hoeflich/MPS
MARINE...Dodd/MPS
TIDES/COASTAL FLOODING...Hoeflich