Area Forecast Discussion
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FXUS61 KOKX 041756
Area Forecast Discussion
National Weather Service New York NY
1256 PM EST Sun Dec 4 2016
High pressure moves across the region from the west today through tonight.
A weak frontal system will then move through on Monday. High
pressure briefly returns for Monday night into early Tuesday,
before giving way to low pressure passing well south of our region
Tuesday night into Wednesday. A rather strong cold front passes
through on Thursday bringing unseasonably cold weather for Friday
into the weekend a well as strong gusty winds.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Forecast on Track as of 1730Z - A slight increase in temperatures
was made based on trends.
Ridging both aloft and at the surface approaches from the west
today with plenty of sun and a gradually diminishing NW flow.
Highs will top out in the lower to mid 40s, which is a few
degrees below normal.
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
Latest NWP as of 1730Z supports current forecast. Basically no
snow accumulation along the coastal plain.
A fast moving, nearly zonal flow across the northern half of the
country will send an upper trough over the Upper Midwest across
the Great Lakes tonight and then up into eastern Canada and
northern New England on Monday. Large scale warm advection
ahead of this system and preceding a surface warm front will
result in a quick shot of light overrunning precipitation late
tonight into Monday morning. Vertical temperature profiles support
mainly light snow inland and a rain/snow mix initially at the
coast. A weak return flow should result in the boundary layer
warming with a quick changeover to all rain at the coast by
daybreak, and by late morning inland. Only looking for about a
tenth of an inch of liquid with temperatures generally above
freezing at the coast, and around freezing across the interior.
About an inch of snow is possible well inland, with perhaps a
a tenth of two across coastal locations outside of the NYC metro.
Some limiting factors for this event are a dry sub cloud layer at
the onset, and then drying aloft in the snow growth region as the
Be alert for some slippery road conditions during the Monday
morning rush for interior locations.
Conditions will quickly dry out by early Monday afternoon with
clearing from west to east by early evening. Highs will be
seasonable in the 40s.
High pressure then briefly returns for Monday night.
.LONG TERM /TUESDAY THROUGH SATURDAY/...
A rather complex period upcoming with two more systems.
1. First system is from the upper low currently over the Gulf of
California. The upper low will weaken dramatically into a minor
shortwave that passes the region Tuesday evening. NWP has
uncertainty in timing. The 00z NAM still appears too fast compared
to the GEFS and deterministic runs. Have maintained low chances
for rain Tuesday afternoon.
Light PCPN becomes likely Tuesday Night...but QPF is < 0.1". Have
kept PCPN all liquid based on profile analysis which has the
freezing level up at 6000` over the interior.
2. Next is the Gulf of Alaska low. The feature deepens the
midwest upper trof on Wednesday and eventually drives a cold front
through the local region on Thursday. There is uncertainty in how
strong the cyclogenesis is over the Atlantic/Maritimes on Friday
and the resultant strength of the CAA and pressure gradient.
For now, have gone with highs near MOS (which may be too warm) and
wind gusts of 25-35 mph (which may be too low). Wind chills get down
into the teens Friday night and stay in the 20s most of Saturday.
Showers on Thursday diminishes in the evening. Flurries for
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
High pressure remains in control through this evening. A weak
front approaches early Monday morning.
VFR through around 06Z before conditions lower to MVFR as light
precipitation overspreads the area before daybreak Monday.
Expecting primarily rain across the city and coastal terminals.
Farther inland, precipitation at KSWF should remain all snow while
KHPN may start as a rain/snow mix before transitioning to all
NW winds will continue through the day before veering to the
NNW-N this evening. An occasional gust to 15-20 kt is not out of
the question this afternoon, but should diminish by sunset. Light
winds overnight will shift to the SE by Monday morning and SW Monday
afternoon at around 10 kt.
.OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY...
.Monday afternoon...Becoming VFR.
.Tuesday...VFR early, then MVFR possible with a chance of light
rain or drizzle.
.Tuesday night-Wednesday...IFR in drizzle and light rain.
.Thursday...MVFR possible with a chance of rain.
Forecast on Track as of 1730Z - no changes at this time.
High pressure moves over the waters today into tonight. A weak
frontal system moves through Monday. Winds and seas remain be sub
Relatively tranquil conditions on the local waters for Monday night
into Thursday. A cold front passing through on Thursday and will
set the stage for potential Gales for all waters on Friday into
Saturday. Outlook for Gales on Friday remains in effect.
No hydrologic impacts are anticipated the next 7 days.