Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 241455

Area Forecast Discussion
National Weather Service New York NY
955 AM EST Sat Feb 24 2018

A warm front approaches the region late today into tonight. A
frontal system will affect the region Sunday. High pressure
builds from the Midwest Sunday night and remains in control
through the middle of next week. A low pressure system may
approach for the end of the week.


Minor adjustments made to temperatures, dewpoints, and cloud
coverage as well as POPs to better match observed trends.
Adjusted 1-2 degrees warmer with temperatures. with a little
more sun expected this morning.

Near zonal upper flow today, with northern stream shortwave tracking
from Ontario into Quebec, and southern stream energy rotating around
southern ridging. At the surface weak high pressure over the region
this morning, will give way to approach of low pressure/s from the
Tennessee/Ohio Valley along a stalled warm front. This will
spell a shot of rain from SW to NE this afternoon into evening.
Forcing with this system is not too strong, so expecting
overall a light rain event.

Temps will run above seasonable with mild airmass in place,
generally upper 40s to mid 50s.


Phasing Sub-tropical and Pac Jet Energy will lift towards the
Great Lakes and NE US tonight into Sunday, with a strong mid-
level shortwave tracking through the Great Lakes tonight into
Sunday Morning. At the surface, strengthening low pressure will
take a similar track, eventually stacking under closing upper
energy across northern Ontario by late Sunday. It trailing cold
front will approach on Sunday with warm front lifting towards
the region late tonight into Sunday, and signal for triple
point low tracking over NYC/LI or just south Sunday aft/early
Sun evening.

Expect increasing likelihood for rain from w to e late tonight
as WCB and divergent upper flow transport and lift a +3-4 std
pwat airmass into the region. This rain will be moderate to
heavy late tonight into Sunday as moisture/lift is focused to
the north of the warm front and in vicinity of the triple pt low
late tonight through Sunday. 1 to 1 1/2 inches of rainfall
likely areawide, with locally higher amounts from orographic

Cold air damming and evaporational cooling early Sunday morning
will likely have temps falling into the mid 30s across interior
valleys, perhaps localized lower 30s. At this point threat for
any freezing rain looks to be low, brief and localized.
Otherwise, temps will likely be hard pressed to rise into the
lower 40s across the interior, particularly valleys, on Sunday,
while coastal areas should be able to rise into the mid to upper
40s. S LI could flirt with 50 degrees if warm front can lift

Shortwave energy pivots NE Sunday evening with the triple pt low and
cold front pushing east, and rainfall tapering off.


The CONUS pattern of troughing in the west and ridging east of
the Rockies looks to continue into next week. The upper pattern
then appears to transition mid to late week next week as a
closed low pres system moves onshore in California early,
continues into the Plains mid week, and then possibly to the
east coast by late week. Uncertainty abounds in the evolution of
this upper energy as the week progresses.

In terms of sensible weather, dry weather returns Sun night as
low pres departs and high pres builds from the Midwest. The high
will remain in control through the middle of next week,
resulting in a continuation of above normal temperatures. Rain
chances will begin to increase Thu as a WAA pattern ensues, although
due to the aforementioned uncertainty in the upper pattern, precip
could very well hold off until Thu night. Predictability is low on p-
type this far out, but lack of cold air supply would favor liquid vs
frozen at this point.


A warm front approaches late today into tonight.

Mainly VFR, however brief vsby restrictions of 3-5SM could occur in
showers that will move in early this afternoon. Can`t rule out MVFR
cigs either this aftn. Flight categories then lower tonight,
eventually bcmg IFR by late.

Light W to NW winds shift NE this evening, then increase from the E
late tonight.

.Sunday...Rain with IFR conds. E-SE winds 10-15kt with
.Sunday night and Monday morning...Chance of rain with IFR conds
in the evening mainly KBDR/KISP/KGON. Areas of fog with IFR/LIFR
conds possible overnight into the morning.
.Monday afternoon through Wednesday...VFR.


Patchy fog along New London Connecticut shoreline will dissipate
late this morning. Otherwise, marine forecast is on track.

Sub-SCA conditions are expected through this evening with weak
high pressure moving across the region.

Easterly winds will increase late tonight into Sunday morning,
with widespread SCA conditions expected. Potential for a period
of marginal gale gusts during this time on the ocean, with seas
building to 6 to 10 ft.

Winds subside Sun Night with high pressure building in, but SCA
ocean seas will likely take till Monday to subside.

Sub SCA conds thereafter with high pressure building from the


Rainfall late today through Sunday is expected to produce
around 1 to 1 1/2 inches of rain, much of it on Sunday. There
could be some locally higher amounts, especially in any areas
of orographic lift.

With saturated grounds, minor poor drainage flooding is
possible on Sunday.


Easterly SCA winds will likely result in 1 to 1 1/2 ft surge and
3 to 4 ft waves into Western LI Sound, which may result in some
localized minor flood/wave splashover in vulnerable areas with
Sunday morning high tide.


NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) is off the
air for an extended period of time.


MARINE...Small Craft Advisory from 1 AM to 6 PM EST Sunday for ANZ330-
     Gale Watch from late tonight through Sunday afternoon for
     Small Craft Advisory from 1 AM Sunday to 7 AM EST Monday for


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