Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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045
FXUS61 KPHI 221716
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
1216 PM EST Wed Nov 22 2017

.SYNOPSIS...
A cold front and low pressure system east of the mid Atlantic
coast will move east of New England by this evening. High
pressure will build toward our area tonight, and control the
weather Thursday and Friday. A cold front is forecast to move
across the mid Atlantic states later Saturday while an area of
low pressure moves northeastward offshore the Mid Atlantic
coast. High pressure builds across the area Monday, then
offshore Tuesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
1150A and 1230 PM ESTF: our new 330 PM office guidance has been
issued with the 1150 AM and 1230 PM ESTF updates. There may
be some minor modifications at 330 PM.

This afternoon...raised temps a bit per obs and added 5MPH to
the gusts (generally 25-35 mph range). Showers now ending NJ
coast. Cold air advection developing nicely. Considerable
cloudiness parts of ne PA and nw NJ but otherwise partly to
mostly sunny elsewhere, except becoming mostly sunny along the
NJ coast.

Tonight...Mostly clear with diminishing gusts...tho still a
breeze in the urban centers and along the coasts where boundary
layer instability is greater with the decent cold air advection.
Lows 4 to 8 degrees below normal.

This forecast was a 50 50 blend of the 12z/22 GFS/NAM MOS.

&&

.SHORT TERM /THURSDAY/...
Sunny with spotty high cloudiness early in the day and then a
general deck of waa mid or high clouds arriving from the west
northwest late in the day reaching to near I-95 around 6 PM.
Light northwest to west wind. Mixing doesn`t look too good so a
fairly chilly Thanksgiving day. Highs 6 to 9 degrees below
normal.

This forecast was a 50 50 blend of the 12z/22 GFS/NAM MOS.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Fairly quiet weather is expected for most of the extended
period through next Tuesday, with a chance of isolated showers
this weekend.

High pressure is forecast to build across the area Thursday
night into Friday and bring dry weather to the region.
Temperatures are forecast to be near or slightly below normal
Thursday, before warming back to near or slightly above normal
Friday.

The high builds offshore Friday night in advance of an
approaching cold front coming through the area Saturday. Also,
an area of low pressure is forecast to be moving northeastward
offshore of the Mid- Atlantic coast on Saturday. This low is
currently expected to remain far enough offshore to not bring
major effects to the area Saturday. However, as the front moves
through Saturday there is a chance of isolated/scattered showers
across the area. For Saturday night into Sunday, the low moves
farther to our northeast with high pressure to our west. This
will keep a strong northwest flow across the area Saturday night
and Sunday. It is possible that some isolated lake effect
showers could make their way across our area Saturday night into
Sunday in the northwest flow. Temperatures remain above normal
Saturday before the front moves through the area, but falls back
to near normal or slightly below for Sunday.

By Sunday night, high pressure begins to approach from the west
and the flow turns more northerly, cutting off the lake effect
showers potential across our area. The high pressure fully
builds across the area Monday, then pushes offshore by Tuesday.
This will bring dry weather back to the area early next week.
Temperatures are expected to be near normal or slightly below
for Monday, then warm back to above normal Tuesday as return
flow develops.

&&

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

This afternoon..VFR sct-bkn clouds aoa 4000 ft. Northwest wind
gusts 25-30 kt.

Tonight...VFR clear with northwest wind gusts diminishing.
Confidence high.

Thursday...VFR clear or some high clouds at times. Northwest to
west wind with gusts under 15 kt. Confidence high.

OUTLOOK...

Thursday night-Friday night...VFR expected. Westerly winds
Thursday- early Friday. Becoming southwest later Friday into
Friday night. High confidence.

Saturday-Sunday...Generally VFR. Isolated showers possible
which may occasionally lower conditions. Southwest winds early
Saturday, becoming northwest and gusting 20-25 knots Saturday
night into Sunday. Moderate confidence on showers and sub-VFR
conditions, high confidence on winds.

&&

.MARINE...
SCA continues as previously advertised. Gusts near 30 kt later
this afternoon.

Will discuss in more detail at 230 PM the diminishing wind and
advisory sitn for Thursday.

OUTLOOK...

Thursday night-Saturday...Sub Small Craft Advisory conditions
expected, although seas may be around 4 feet Thursday before
subsiding.

Saturday night-Sunday...Small Craft Advisory conditions likely
behind cold frontal passage.

&&

.EQUIPMENT...
The KDOX radar remains out of service. Replacement parts are
expected to arrive today.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 6 AM EST Thursday for ANZ450>455.
     Small Craft Advisory until midnight EST tonight for ANZ430-431.

&&

$$
Synopsis...Drag/Robertson
Near Term...Drag 1216
Short Term...Drag 1216
Long Term...Robertson
Aviation...Drag/Robertson 1216
Marine...Drag/Robertson 1216
Equipment...



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