Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 270354
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
1154 PM EDT THU MAY 26 2016

.SYNOPSIS...
High pressure is anchored over the western Atlantic through this
weekend while low pressure between Bermuda and the Bahamas moves
northwest toward South Carolina. A cold front will organize over
the Great Lakes early next week passing through our region by the
middle of the week. The low pressure system near the southeast
United States coast may linger there most of next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
Overnight...variable cloudiness. Isolated sprinkles in southeast
Pennsylvania may develop northeast toward northern NJ during the
night? Quite mild.  Light south wind.

Friday...Very warm and more humid with a potential for D2 of 90F
temps at KABE/KPHL/KPNE/KTTN/KACY/KGED/KESN. Depends on how much
sunshine. Best chance for 90F temps is near and north of I-78
possibly extending down to KPHL? Airmass is as warm as ydy with
higher dewpoints. More cloud cover may make it more difficult to
maximize heat potential. South to southwest wind with afternoon
gusts 15 mph. Convection: Possible..more details at 330 am or
sooner. PWAT about 1.7" for a 571 1000-5000 thickness.

From the 930 pm Thursday discussion below...

A pool of instability is anticipated to form over central Pennsylvania
with scattered showers and thunderstorms expected to develop in
that area. The convection should drift eastward into our forecast
area during the afternoon. We will mention a chance of showers and
thunderstorms mainly for our counties in eastern Pennsylvania and
northern New Jersey. PoPs were lowered a bit with the 930 PM ESTF
update as it appears that models, in particular the NAM/GFS, are
overdoing the low-level moisture/instability and thus convective
potential. There also doesn`t appear to be much organized lift
present across the area until perhaps a shortwave trough
approaches from the west toward sunset.


&&

.SHORT TERM /FRIDAY NIGHT/...
Fair and mild. Much more detail at 330 am.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Saturday through Sunday Night: High pressure will be firmly in place
over the region. Subsistence from the high pressure will prevent
normal pop-up afternoon thunderstorm formation both days except in
the higher terrain areas in the Southern Poconos and NW NJ. A
gradual tick upward with humidity is expected, making it feel even
more like summer. High temperatures will likely be a couple degrees
warmer than met/mav with overnight lows climbing due to the
increased humidity.

Memorial Day: A low pressure system is likely to be located just off
the Southeast United States coastline. With a broad mid-level ridge
just offshore moisture is likely to be transported northward along
the eastern seaboard. Some uncertainty is present with this low
potentially become tropical. The National Hurricane Center currently
has a 70% chance of this forming into a sub-tropical or tropical
system between today and early next week.

While any tropical impacts would be well south of the region, the
moisture interaction with lift along an approaching cold frontal
boundary. This will lead to a good chance of showers and
thunderstorms with a heavy rainfall threat. PW values are also
modeled to approach 2 inches along with a modeled long-skinny CAPE
profile both also suggesting the prospects for heavy downpours with
thunderstorms. Temperatures will likely be kept down as well due to
cloud cover and thunderstorms.

Monday night through Tuesday night: The cold frontal boundary will
likely continue to be close to the region and serve as a focal point
for additional scattered showers and thunderstorms, potentially
moving through by Tuesday. With the more scattered coverage of the
showers and storms, daytime temperatures will rebound a bit on
Tuesday after a muggy start.

Wednesday and Thursday: Another low pressure system and cold front
will move into the Central Plains with our region in the warm sector
with high pressure to the northeast. However, mid level temperatures
look cooler than with the warm-up this weekend. Forecast close to
WPC guidance.

&&

.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Remainder of overnight...VFR with isolated showers possible vcnty
KRDG/KABE. Light south to southwest wind.

Friday...VFR with sct-bkn aoa 5000 ft. South to southwest wind
gusting around 15 kt during the afternoon. Chance of a shower or
tstm but not in the TAFS till more convinced of nearby passage of
any convection.

Friday night...VFR. Light south to southwest wind.

OUTLOOK...

Saturday through Sunday: Mainly VFR, southerly winds 5-10 knots
with gusts around 15 knots Saturday and Sunday afternoons.
Isolated thunderstorms possible for KABE.

Sunday night through Monday night: MVFR/IFR ceilings possible.
Periods of showers and thunderstorms, the highest chance of
thunderstorms is on Monday. Southerly winds up to 15 knots.

Tuesday: Mainly VFR, winds under 15 knots. An isolated
thunderstorm is possible.

&&

.MARINE...
No marine headlines through Friday night.

Southerly flow persists...at times gusty to 15 or 20 kt. Seas
generally 1-3 ft. More conservative NWPS wave heights will
probably be used for the 330mam Friday forecast.


OUTLOOK...
No marine headlines anticipated.

&&

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

&&

$$
Synopsis...Gaines/Robertson
Near Term...Drag 1153
Short Term...Drag/Iovino 1153
Long Term...Gaines
Aviation...Drag/Gaines 1153
Marine...Drag/Gaines 1153



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