Area Forecast Discussion
Issued by NWS Upton, NY

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187
FXUS61 KOKX 242044
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
344 PM EST Sun Nov 24 2024

.SYNOPSIS...
High pressure will be in control through Monday. A cold front then
approaches Monday night and passes through on Tuesday. Low pressure
will likely impact the area during the end of the week.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
The pressure gradient over the region weakens as low pressure over
the Canadian Maritimes shifts east and a weak high pressure ridge
moves in from the west. Still gusty this evening, with lighter winds
overnight. Leaned toward the warmer side of guidance for low
temperatures, more so over coastal sections where a mixed boundary
layer will have greater influence. Lows near 30 well inland to
around 40 NYC metro.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
High pressure ridge at the surface and aloft shifts into the area on
Monday. Winds will be lighter from the west, and high temperatures
will be near normal at 50-55.

A longwave 500mb becomes negatively tilted as it moves across the
Upper MS Valley/Great Lakes Monday night. This will strengthen a
surface low that will track through Great Lakes and head into
Southern Quebec during Tuesday. Models suggest that a secondary low
center develops over us or southern New England on Tuesday. Rain
begins to be possible after midnight Monday night ahead of an
attendant warm front, but will be most likely during Tuesday as a
trailing cold front passes through late morning/midday. Conditions
should at least improve in the afternoon. High temperatures will
still manage to climb above normal levels with the help of SW to W
winds. Highs 55-60 for most spots.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
The main fcst challenge is the storm sys for the end of the week.

High pres builds in S of the cwa for Wed. This produces fair wx with
temps near normal and a wly component breeze. The NBM was used for
most fields.

The modeling does not produce a high confidence fcst thereafter. The
12Z ECMWF continues the idea of a fairly deep, organized low
tracking thru the cwa on Thanksgiving. Depth is in the low 990s.
This soln is very similar to the 00Z run, and a trend sewd from the
12Z run yesterday. The 12Z GFS has rebounded back to an offshore but
close track with a weaker low, similar to many previous runs minus
the outlying 00Z and 06Z runs.

Incorporating the GFS persistence with the ECMWF trend, went with a
colder than NBM fcst based off a track S of LI, with rain or snow
for the nwrn interior and rain elsewhere. The MEX guidance was used
for temps Thu-Fri, with the NBM too warm based on the conceptual
model of the warm sector staying mainly S of the area. If the storm
does end up further N, the temps will likely soar thru the 50s at
the coasts and all areas will see rain until perhaps the very end
when the low exits. A track S of the area with the right intensity
could bring a snow event, particularly across the interior, so there
is room to adjust either way with this fcst.

Wind impacts are possible if the ECMWF track, timing and intensity
verify. A strong sely flow Thanksgiving mrng into the aftn is
possible if the low does track invof or N of NYC during that period.

Pops are still in the fcst for Fri, although the 12Z runs suggest
most of the pcpn will be over. Lowered the NBM numbers but did not
eliminate altogether this far out.

NBM pops were reduced to dry Sat-Sun however. The models may be
picking up on too much ocean effect as a cold airmass builds in.
There could be chances for some flurries or shsn at times, but
probs/timing/coverage confidence all too low attm to include.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
High pressure slowly builds in from the west tonight as low pressure
over the Canadian Maritime weakens and moves east into early Monday.
The high builds over the region Monday.

VFR.

Gusty W to NW winds have begun to diminish especially across the NYC
metro area as high pressure builds slowly toward the area. Gusts and
winds continue to diminish this evening with gusts ending 01Z to
02Z. A lighter, 10kt or less, WNW flow then continues into Monday
morning.


 ...NY Metro (KEWR/KLGA/KJFK/KTEB)TAF Uncertainty...

No unscheduled amendments expected.


OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY...

Monday afternoon: VFR.

Tuesday: Showers with MVFR, periods of IFR possible. Showers ending
late in the afternoon into the evening, becoming VFR. SW winds
gusting 20-25kt along the coast..

Wednesday: VFR.

Thursday: MVFR/IFR with a chance of showers.

Friday: VFR with a chance of showers. MVFR with rain and snow
showers at KSWF. NW/W wind gusting 20-25kt.

Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90

&&

.MARINE...
No changes to the headlines at this point. A SCA is in effect for
all ocean zones through tonight, and might need to be extended a
little into Monday morning east of Moriches Inlet. SCA remains
elsewhere, although there`s a chance that gusts could still reach
advisory criteria on eastern LI Sound and Peconic/Gardiners Bays for
a fews hours after the advisory expires at 1 AM late tonight. High
pressure and a weak pressure gradient will otherwise bring
relatively tranquil conditions on all waters Monday and Monday
night. Winds and seas then increase Tuesday with the passage of a
cold front. Advisory thresholds will probably be reached on the
ocean during Tuesday.

Winds and seas blw sca lvls on Wed, then cond deteriorate on
Thanksgiving as low pres impacts the waters. Gales possible into
Fri, with sca cond likely on Sat.

&&

.HYDROLOGY...
No hydrologic impacts are expected through the weekend.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 1 AM EST Monday for ANZ331-332-335-
     340-345.
     Small Craft Advisory until 6 PM EST this evening for ANZ338.
     Small Craft Advisory until 6 AM EST Monday for ANZ350-353-355.

&&

$$

SYNOPSIS...JMC/JC
NEAR TERM...JC
SHORT TERM...JC
LONG TERM...JMC
AVIATION...MET
MARINE...JMC/JC
HYDROLOGY...JMC/JC