Area Forecast Discussion Issued by NWS Upton, NY
000
FXUS61 KOKX 252049
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
349 PM EST Thu Feb 25 2021
.SYNOPSIS...
High pressure builds in for Friday. A frontal system impacts
the area Friday night and Saturday. Another frontal system moves
through the region Sunday into Monday. High pressure briefly
returns Tuesday. Another frontal system may impact the area
Wednesday and Thursday.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Winds continue to decrease this eve as a 1031 high over the Midwest
builds ewd. The combination of a weakening pres grad and diurnal
cooling should allow winds to become lgt aft dark, especially
away from the immediate shore. Mainly clr skies will allow for
good radiational cooling. The vis stlt shows much of the snow is
gone for LI and NYC, with more elsewhere. The NBM looked to
reflect that decently in the overnight low temp field, so the
guidance was accepted with minimal changes made.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Strong subsidence on Fri so sunny skies can be expected. Winds lgt
with the high building right over the cwa. The NBM was used for
temps which was a few degrees blw climo.
The high builds offshore Fri ngt with a warm front passing n of the
area. The models are in good agreement with pcpn breaking out in the
waa pattern between 6-9Z across the swrn portion of the area, and 9-
12Z elsewhere. The cold air is progged to erode quickly, but it does
look likely to hold in long enough for at least a wintry mix at the
onset across the interior. Mainly snow and sleet changing over to
rain is expected, but across some portions of the interior, there
could be a bit of fzra as well where the llvl cold air is locked in
a bit longer. The favored area for this is across nwrn Orange
county, and a hundredth of icing has been added to the fcst. Any
period of icing is expected to be brief attm, with the pattern not
conducive to significant cad. The 15Z sref was used for pops and
timing, and the NBM along with CONSALL was used for temps, which
should rise overnight.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
A weak low center embedded within a broad area of low pressure
shifts through on Saturday with rain likely. Mixed PCPN for the
first few hours of the morning NW of the city before thermal
profiles warm up for all rain by noontime. Total snowfall is
expected to be under an inch. Rain should end by sunset for most
places, then weak ridging supports dry weather Saturday night.
Another weak low center then approaches us on Sunday with rain
likely, and if it begins early enough, locations well NW of the city
could see it briefly mix with sleet due to wet-bulbing. Models have
the low passing just offshore Sunday evening with lingering rain
chances, then a surface trough moves in with moisture convergence,
maintaining chances of rain overnight. Drying of the atmospheric
column occurs on Monday with a westerly flow setting up ahead of an
approaching cold front. The cold front passes through dry, and it
becomes breezy in the afternoon. An upper trough axis and shortwave
then pass through Monday night. Not much moisture depicted by the
models, but still included a chance of flurries during the period.
Remaining breezy as well.
Deep-layered ridging then occurs for Tuesday with dry conditions.
ECMWF and GFSv16, and to a lesser degree GDPS, then show a broad
area of low pressure that could bring mainly rain to the forecast
area Wednesday-Thursday. Will go with only chance PoPs for now for
this period.
High temperatures will be in the 40s through the long term forecast,
with the exception of Tuesday when it will be mostly 35-40.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
VFR all terminals as high pressure builds in. The high moves
overhead late tonight into Friday morning and offshore late Friday
morning into Friday afternoon.
Winds are WNW/NW 10-15 kt. Gusts have generally diminished, but
occasional gusts of 20-25 kt are still possible through 00Z. Winds
become less than 10 kt overnight tonight as the center of high
pressure moves overhead. They may actually become light and
variable, especially some of the outlying terminals. Winds then
shift toward the S late Friday morning into the early afternoon.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments possible if gusts continue longer than forecast.
.OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
.Friday...VFR.
.Saturday...MVFR or lower with rain. A wintry mix possible at the
onset, mainly for KSWF.
.Sunday...Chance of rain and MVFR.
.Monday...Strong NW winds possible behind a cold front.
.Tuesday...VFR. NW winds gusts 20-25 kt possible.
Detailed information, including hourly TAF wind component forecasts,
can be found at: http:/www.weather.gov/zny/n90
&&
.MARINE...
Winds and seas have come down this aftn, and the sca will be
canceled for all waters. Winds and seas are then expected to remain
blw sca lvls thru Fri ngt.
Winds and seas increase to advisory levels on Saturday ahead of an
approaching low pressure system, with seas remaining elevated due to
a lingering swell in the storm`s wake. Elsewhere, gusts to 25 kt
will be possible primarily over the eastern Sound and Bays on
Saturday. Seas up to 5 ft may still linger on the ocean through
Sunday night with a weak low center passing through the area waters.
A cold front then passes through on Monday with cold air advection
perhaps strong enough to create gale force gusts on some of the
waters - if not at least SCA conditions through Tuesday morning.
High pressure then settles in with more tranquil conditions by the
end of Tuesday.
&&
.HYDROLOGY...
No hydrologic impacts are anticipated through Wednesday.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JMC/JC
NEAR TERM...JMC
SHORT TERM...JMC
LONG TERM...JC
AVIATION...JP
MARINE...JMC/JC
HYDROLOGY...JMC/JC