Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 020729

Area Forecast Discussion
National Weather Service Mount Holly NJ
229 AM EST Fri Dec 2 2016

A strong low pressure system will continue to move slowly through
northeastern Canada over the next couple of days keeping a cool
northwest flow over our region. High pressure over the Ohio Valley on
Saturday will move into the area on Sunday and then will move off to
the northeast late Monday. A complex low pressure system will track
through the plains into the midwest and impact our weather through
the mid week period.


Through sunrise... patch of clouds over the Delmarva is unexplained
and slowly dissipating. Otherwise...mostly clear with a west wind.

Today... A sunny or mostly sunny day south but considerable cloudiness
develops ne PA and nw NJ with midday heating. Chance of flurries in
the Poconos later today or this evening per the 500 mb vort lobe
swinging sewd from Quebec. BTV snow squall parm has small
indicator of snow shower potential far ne PA. Temps/winds were a
blend of the 00z/2 GFS/NAM MOS. Raised guidance temps 1-2F per the
EC 2m 18z temp of 49F at PHL. These fcst temps are a deg or two
above normal. Winds should become gusty 20-25 mph midday or this


Clear to Partly cloudy except plenty of clouds nw edge of the fcst
area from lake effect and still a chance of flurries in the Poconos.
West-northwest wind a bit stronger than what it was predawn today.
Fcst was a 50 50 blend of then 00z/2 GFS/NAM MOS. Resultant fcst
lows are a couple degrees warmer than normal.


Saturday and Sunday...High pressure will start to build towards the
region on Saturday, reaching our area on Sunday. For the most part
we should remain dry during this time frame. Saturday will be
cloudier than Sunday but overall both days make for a decent
weekend. The northwest flow will remain and this will keep the
temperatures on the cool side, moreso on Sunday than on Saturday.
Highs will generally remain in the 40s, near 50s south and in the
30s across the north. Overnight lows both nights will range from
the upper 20s to low to mid 30s across the area.

Increasing cloudiness arrives in advance of an approaching
weakening shortwave. A shortwave arrives Sunday night but
enough moisture may be around for some light rain or snow showers.
We maintain low pops for Sunday night with the best chances to the
north and west of Philadelphia.

Monday through Thursday...The surface high starts to weaken as
strengthening low pressure near the Gulf of Mexico starts to move to
the northeast. The low moves into the Ohio Valley on Tuesday and
then splits. The southern low will track just south of our area as
it moves off to the east. The northern low tracks northward and into
the Great Lakes region. This split system will bring in some more
much needed moisture to the region. Precipitation will move in late
Monday night into Tuesday morning. As the low moves across Delmarva
and offshore, we should see the heavier rain across our southern
zones. With cold air in place, there will be a chance for some mixed
precipitation or rain changing to snow, mainly north of the I-95
corridor. A cold front will then drop down from the northwest and
cross the region Wednesday into Thursday. This feature should bring
more steady precipitation to our northern zones, where drought
conditions are ongoing. Temperatures are expected to be near normal
through through midweek.


The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.

Through today... VFR few clouds aoa 4000 ft. light west wind before
sunrise becomes gusty 20-25 kt midday and this afternoon.

Tonight...clear or sct clouds aoa 4000 ft. West-northwest wind
may be gusty to 15 kt.


Saturday through Sunday...mainly VFR conditions are expected. West
to northwest winds around 10 to 15 knots expected with gusts up to
25 knots Saturday afternoon. Winds are expected to be less gusty
on Sunday.

Sunday night through Tuesday...mainly VFR conditions are expected.
Rain or snow showers are possible late Sunday night into Monday
morning and then again late Monday night and Tuesday. Best chances
for precipitation exist to the north and west of KPHL.


SCA continues for lower DE Bay but also the Atlc waters. Appears
guidance is running a little low and has been for the past 18 hours.
Surface and boundary layer temps at or below the SST permitting
decent transfer, at least in the lowest 25 to 50 MB adjacent the
sfc. Winds may lull for a few hours midday. Isolated gale force
northwest wind gusts possible late tonight in lower De Bay.


Saturday...Increasing winds, especially late Friday night,
expected as cold air advection takes place over the waters. Strong
northwest flow of 20 to 25 knots with gusts up to 30 knots on the
ocean. Winds will start to subside late Saturday. Seas will also
increase into Saturday but look to remain just below 5 feet. A
Small Craft Advisory will likely be needed. There is also a small
possibility for same gale force gusts but confidence is low at
this time.

Sunday and Monday...Sub-advisory conditions are expected on the area
waters as high pressure builds into and over the region.

Tuesday...a low pressure system will move into the area. Seas will
start to build on Tuesday and may exceed 5 feet. A Small Craft
Advisory may be needed.


MARINE...Small Craft Advisory until 5 AM EST Saturday for ANZ431-


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