Area Forecast Discussion
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FXUS61 KOKX 250251
Area Forecast Discussion
National Weather Service New York NY
951 PM EST Fri Feb 24 2017
As high pressure moves out to sea, a cold front will approach late
Saturday, then sweep east across the area Saturday evening. High
pressure will then build in through Sunday, and pass east Sunday
night into Monday. A warm front will move through Tuesday into Tuesday
night, followed by an approaching cold front on Wednesday.
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
South winds continue to transport unusually mild and moist air north
across the area as high pressure moves out to sea.
The latest loop of 11-3.9 micron sat imagery shows multiple areas
of BKN low level stratus clouds advecting north and rapidly expanding
north and east mainly east of the Hudson River through 0230z. Dense
fog developed at KGON with a vsby of 1/4 mile and KJFK was reporting
1/2 mile in fog.
Look for this trend to continue with expansion occurring west of
the Hudson River by midnight.
We continue to monitor for the development of widespread dense fog.
Confidence is not high enough for widespread dense fog at this time.
Otherwise, lows tonight should be fairly uniform in the upper 40s
and lower 50s, unusually mild for late February.
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Expect the fog to hang on into at least Sat morning, then lift,
except perhaps along the immediate coast Sat afternoon. Once the
fog and clouds break expect another mild day, with highs in the
upper 50s and 60s.
Chances for showers and a few tstms will increase in the afternoon
and evening as the cold front approaches and passes through,
mainly from NYC north and west. Any storms could produce a
brief downpour and gusty winds mainly in this area, where
instability, while marginal would be more likely to be surface-
Highs on Sat could be a few degrees cooler than fcst if fog and
low clouds continue into Sat afternoon. This would make most of
the instability elevated in nature except perhaps right with
cold frontal passage itself. With some model guidance showing a
good push of westerly winds right behind the front and low
level thermal profiles going quickly dry adiabatic, this could
be a situation where convection right along the front could
produce strong winds even out over the more stable marine layer
to the east.
Gusty NW flow and cold/dry air advection later Sat night, with
precip chances waning and lows in the 30s.
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Zonal flow aloft Sunday, with the center of high pressure over the
Tennessee Valley. Northwest flow will usher in a colder air mass,
allowing temperatures to come down to near normal levels for this
time of year.
The high quickly pushes off the Mid-Atlantic Coast Sunday night,
allowing for weak warm air advection to begin and continue into
Monday. Highs will once again be above normal, in the upper 40s to
lower 50s across the entire area.
A warm front approaches the area Monday night into Tuesday.
Overrunning moisture out ahead of the front will give the area
increasing chances for precipitation beginning late Monday night for
western portions, then for the entire area Tuesday morning as the
front continues its approach. Temperature profiles look to warm for
any frozen or freezing precipitation, except may be a brief period
of mixed rain and snow showers for northern Orange County.
Models differ on placement and timing of the warm front, this also
leads to differences in where the axis of heavier precipitation will
be. Both the 12Z ECMWF and the 12Z GFS develop a low along this
frontal boundary, however, the ECMWF is quicker to develop this low,
and thus has an axis of heavier precipitation over the tri-state,
while the GFS is slower and shunts the heaviest precipitation to the
The area will be warm sectored Tuesday, allowing the warm advection
to continue. Highs will continue to be above normal, upper 40s to
middle 50s. Cooler conditions along the shore with southerly winds
off the relatively cool ocean waters.
There may be a brief respite in precipitation for the area late
Tuesday night as any forcing associated with the warm front lifts
north with the front, though there remains a slight chance for a
shower. Another round of showers is expected with a cold front
approaching Wednesday and moving through Wednesday night.
Temperatures continue to warm out ahead of the approaching cold
front. Highs on Wednesday will be in the 50s for much of the region.
Some upper 50s for the New York City metro area, while coastal
sections will once again remain in the upper 40s to near 50. GFS is
too progressive as usual, moving the front through during the day
Cooling trend then expected as cooler air moves in behind the front
through at the end of the week. By next Friday, temperatures will be
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Weak high pressure remains over the terminals tonight, then a cold
front moves through late day/early evening Saturday.
Stratus development and advection so far is affecting KJFK/KHPN and
points east, bypassing KLGA. Still anticipating an eventual westward
expansion. Expecting all terminals to eventually lower to IFR.
Timing of when this occurs at KLGA and points west is uncertain,
and TAFs could be off probably in the order of 1-3 hours.
Stratus and some fog then remain likely for Saturday morning with
IFR, then IFR cigs in the afternoon with late-day early evening
showers with possible thunderstorms.
.OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY...
.SAT NGT...Improving to VFR with a COLD Frontal Passage around 00Z
that will included at least SCT Convection. WNW Wind G25 KT after
.SUN...VFR. NW WND G25KT
.TUE...MVFR with areas of IFR in showers.
.WED...Improving to VFR. W WND G20KT.
A Dense Fog Advisory remains in effect for all coastal waters
until Noon Saturday for VSBY 1 NM or less.
A low pressure system off the southeast coast will produce
SE swells across the Atlantic Ocean coastal waters with seas
above 5 ft. Sat into Sat evening before a strong cold frontal
passage. Winds after fropa likely to gust up to 35 kt, therefore
a Gale Watch has been issued for Sat night for the ocean
waters. This may need to be expanded in area and in time to the
remaining waters and into Sunday as well.
Winds will diminish Sunday night as low pressure tracks away
from the area. Winds then generally remain below 25 kt through
Wednesday night. SCA gusts then possible over all waters on
Thursday, and then just the ocean waters Thursday night as a low
pressure system over the Gulf of Maine intensifies then moves
away from the area.
Ocean seas will also diminish late Sunday into Sunday night,
coming below 5 ft everywhere around sunrise Monday. Thereafter,
waves should remain generally below 5 ft through the day
Waves build Tuesday night in response to increased southerly
flow as a warm front lifts north of the region. Ocean seas up to
5 ft are possible on Wednesday, and could continue to build to
5-7 ft by Thursday morning. Waves diminish in the afternoon as a
cold front pushes offshore late Wednesday night, allowing
winds to shift to more of an offshore flow.
Basin avg rainfall of 1/4 to 1/2 inch is likely on Saturday,
with local amounts up to double that which could cause
associated isolated nuisance ponding. Higher amts NW of NYC.
The following are record high minimum temperatures for Saturday
February 25, 2017 along with the forecast minimum temperature.
Record High Min Temperature Forecast Min
Central Park........51 (1930) 56
LaGuardia...........49 (1996) 53
Kennedy.............46 (1996) 50
Islip...............47 (1996) 50
Newark..............47 (1996) 53
Bridgeport..........44 (1996) 50
MARINE...Dense Fog Advisory until noon EST Saturday for ANZ330-335-338-
Small Craft Advisory from 6 PM Saturday to 6 AM EST Sunday for
Gale Watch from Saturday evening through late Saturday night
Small Craft Advisory from 6 AM to 6 PM EST Saturday for ANZ353-
Small Craft Advisory from noon to 6 PM EST Saturday for ANZ350.