Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 251831

Area Forecast Discussion
National Weather Service Mount Holly NJ
231 PM EDT Tue Oct 25 2016

High pressure near James Bay Canada will nose down into region Wednesday.
A warm front on Thursday will be followed by a cold front Thursday night
as low pressure redevelops from near Lake Erie Thursday to Long Island
early Friday morning. Weak high pressure quickly follows Friday night
before low pressure and its associated frontal systems cross the mid
Atlantic states this weekend. High pressure will become dominant over
our area by next Monday.


Remainder of this afternoon...Clouds clear late in the day but
gusty northwest winds to 20 and 25 mph continue. The sprinkles
(first flurries of the season were reported at Lake Harmony and
High Point- Wantage this morning).

Tonight...Frost Freeze continues as previously advertised. Will
repost the NPW around 3PM with only cosmetic changes.

12z GFS and GGEM are steadfast regarding their 2m temp and tsection
rh fcst overnight. frost-freeze. 09z/25 SREF PWAT of .25" is even
further south than yesterdays modeled guidance for 12z/26. It may
take a while for decoupling due to the constant caa but shortly
after 05z, am expecting a notably drop in wind and the radiating
countryside should soon be done with the growing season, even if
the urban centers remain just above freezing.

Philly metro and surrounding PA suburbs, Cape May County, and
much of Delmarva, have a frost advisory for less risk of damaging
near 32F for an hour or two near the approximate 725 am sunrise.

The NJ shore and DE beaches, where winds may stay up through much
of the night due to heat sink water temperatures in the upper 50s,
looking to keep the wind actively drawing cooler land airmass
toward the water should prevent frost or a freeze.

The growing season has already ended in the poconos and far
northwest NJ.

Forecast basis: 50 50 blended 12z/25 GFS/NAM MOS then lowered 1
degree in parts of northwest NJ and and eastern PA.

These low temps should average 5 to 7 degrees below normal, which
means far from a record and its seasonally about the time the
growing season ends in a larger section of PA and NJ.

Forecasters during the day tomorrow will post a note in this AFD,
also via a PNS, about what counties met the requirement of 50
coverage of below freezing temps to end the season.


Variably thin bands of cirrus will allow plenty of sunshine, however
much less wind will also limit mixing potential. Max temps a few degrees
cooler than they were this Tuesday afternoon and again about 5 to
7 degrees below normal. Quite a nice fall day.

This part of the forecast was based on a 50 50 blend of the
12z/25 GFS/NAM Mos, modified slightly warmer by the 2m temps of
the 12z EC. For PHL thats 51F, so that should mean a high of 55 in


Wednesday night and Thursday...Still model disagreement at this
time with regard to precip amounts, thermal profile, and precip
type across northern NJ and the Poconos. The NAM continues its
trend of keeping the bulk of the precip northwest of the CWA,
while the GFS and ECMWF are in good agreement, indicating a band
of overrunning precip, focused north of the I-78 corridor. We
adjusted the precip starting time later, just after midnight on
Thursday morning. The column is below freezing to start, and with
the addition of wet bulb cooling, this will initially favor light
snow. Model soundings indicate the lack of a warm nose aloft, so a
gradual changeover to rain and even some spotty freezing rain is
likely by Thursday morning, although cannot rule out a period of
sleet. Any accumulation of snow and slippery travel will be more
confined to Sussex and Monroe counties, generally less than one
inch at this time. Otherwise, locally heavy rain showers for the
remainder of the area, with southerly winds gusty at times.

Thursday night and Friday...Precipitation ending from west to east
Thursday night with a blustery northwest flow to follow. Friday
will feature fair weather.

Saturday through Monday...Still considerable uncertainty, with
model timing differences, taking low pressure across the area
this weekend. Fair weather will return by Monday. Temperatures
are expected to rebound closer to normal during this time frame.


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

Rest of this afternoon...VFR sct-bkn aoa 5000 ft. Northwest wind
with gusts 22 to 28 kt, diminishing late with cloud cover thinning
and dissipating to scattered cloud or skc by 22z.

Tonight...VFR clear. Northwest winds may still be gusting around
20 kt through 04z/26 vcnty KPHL/KACY but will gradually decouple
and decrease toward 09z/26.

Wednesday...VFR bands of variably thin cirrus aoa 20000 ft.
Northwest wind becoming north late in the day.

Wednesday night and Thursday...MVFR at times with a gusty south
wind on Thursday.

Friday and Saturday...VFR. Gusty northwest winds at times.


SCA headline on the Atlantic waters may be extended 2 hours.

Winds will continue to gust near or just above 25 kt on all the
waters through the afternoon. On the ocean waters, SCA conditions,
primarily for winds could linger into late this evening, and even
after midnight we could continue to see winds gusting above 20 kt. marine headlines anticipated.

SCA likely Thursday into Friday, otherwise sub-SCA.


Our forecast indicates October should average 2 to 3.5 degrees above
normal for PHL and ABE. Forecasts are trending warmer beyond Thursday.
This should result in average temperatures ranking between 15 and
20th warmest Octobers on record. This is only noteworthy in that
the excessive monthly warmth of July, August, September eased in
October. Will reevaluate around 4PM.


PA...Freeze Warning from midnight tonight to 9 AM EDT Wednesday for
     Frost Advisory from midnight tonight to 9 AM EDT Wednesday for
NJ...Freeze Warning from midnight tonight to 9 AM EDT Wednesday for
     Frost Advisory from midnight tonight to 9 AM EDT Wednesday for
DE...Freeze Warning from midnight tonight to 9 AM EDT Wednesday for
     Frost Advisory from midnight tonight to 9 AM EDT Wednesday for
MD...Freeze Warning from midnight tonight to 9 AM EDT Wednesday for
     Frost Advisory from midnight tonight to 9 AM EDT Wednesday for
MARINE...Small Craft Advisory until 11 PM EDT this evening for
     Small Craft Advisory until 6 PM EDT this evening for ANZ430-


Synopsis...Drag/Franck 230
Near Term...Drag/Johnson 230
Short Term...Drag/Johnson 230
Long Term...Franck
Aviation...Drag/Franck/Johnson 230
Marine...Drag/Franck/Johnson 230
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