Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 221644
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
1244 PM EDT Tue May 22 2018

.SYNOPSIS...
A warm front will lift across the area into this evening as an
area of low pressure moves from the Great Lakes region into New
York state. A cold front will then move across the area tonight
into Wednesday morning. High pressure will build across the area
Thursday, then offshore Friday. A backdoor cold front is
forecast to move southward across the area late Saturday, while
a warm front may lift into the area Saturday as well. These
fronts may stall near the area into early next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A warm front extended from the eastern Great lakes, across
central Pennsylvania to the middle Delmarva around noontime. The
boundary will progress slowly to the northeast and it should
move farther into our region this afternoon.

Rain showers will continue. Also, conditions will destabilize
on the warm side of the front. Mixed layer CAPE values are
anticipated to reach 500 to 1000 J/Kg on the Delmarva. We will
continue to mention scattered thunderstorms for this afternoon.
Even in the northeastern part of our forecast area where
conditions will remain fairly stable near the surface, there may
be enough instability aloft to result in some thunder.

A southeast to south wind around 5 to 10 MPH is expected.
Maximum temperatures will range from the 60s in the Poconos and
in northern New Jersey to the upper 70s in southern Delaware and
in the adjacent counties of eastern Maryland.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
The low to the north will pull away and begin to move down the
St. Lawrence valley tonight. An associated cold front will begin
to approach the area. This will bring a continuation of the
unsettled conditions from the daytime. More showers and sct
tstms will be around, mostly during the evening and early
overnight periods. Again local downpours and gusty winds with
ant tstm. The higher pops will be across srn NJ and Delmarva. It
will remain warm and humid tonight with lows only dropping into
the low/mid 60s in most areas and some 50s across the far N and
NW.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Quiet conditions start off the extended period, then unsettled
forecast returns by the weekend into early next week, although
there is some uncertainty.

On Wednesday, the cold front will continue to push to our east
early in the day, so there may still be some lingering showers
very early in the day. However, as the front continues to push
southward, the showers should end by midday and dry weather will
move into the area into Wednesday night.

High pressure will build across the area on Thursday, before
pushing offshore Friday. This will provide dry weather, with
warming temperatures.

Then the uncertainty begins to build across the area over the
weekend into early next week. High pressure remains offshore
Saturday, which will keep strong return flow across the area,
leading to another day of warmer than normal temperatures. Then
a backdoor cold front is forecast to advance southward toward
the area later Saturday evening. Meanwhile, a warm front could
be lifting northward into the area from the south as well. The
fronts would merge into one stationary frontal boundary and
linger near the area into early next week. As multiple short
wave/vorticity impulses move across the area over the weekend
into early next week, this could lead to several periods of
unsettled weather from late Saturday through at least Monday.

&&

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

This afternoon...VFR varying to MVFR in precipitation with
localized IFR conditions in moderate to heavy rain. Scattered
thunder is anticipated. Southeast to south wind 5 to 10 knots.

Tonight...Precipitation ending before 01z. A line of weakening
showers may approach KRDG and KABE around 03z. MVFR and IFR
conditions are anticipated with a light and variable wind.

OUTLOOK...
Wednesday-Wednesday night...Becoming VFR. Showers possible
early. NW winds may gust around 15-20 knots in the afternoon.

Thursday-Thursday night...VFR. N winds may gust around 15-20
knots at times during the day.

Friday-Saturday...VFR. Southwest winds may gust 15-20 knots
during the day. Showers possible late Saturday.

&&

.MARINE...
Overall, sub-SCA conditions are expected across the waters
today. An increasing wind today with directions SE to S. The
direction will continue to veer to SW tonight. Scattered showers
and a few tstms are expected. Locally higher winds and seas
near tstms can be expected. Seas on the ocean will mostly be 2
to 3 ft this afternoon and tonight.

OUTLOOK...
Wednesday-Thursday night...Sub Small Craft Advisory conditions
expected.

Friday-Saturday...Winds and seas begin to increase and may
approach Small Craft Advisory levels.

&&

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

&&

$$

Synopsis...Robertson
Near Term...Iovino
Short Term...O`Hara
Long Term...Robertson
Aviation...Iovino/Robertson
Marine...Robertson/O`Hara


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