Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 181845
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
145 PM EST Tue Feb 18 2020

.SYNOPSIS...
A warm front approaching from the south will lift into the area
by this evening as weak low pressure develops along it. A weak
cold front will follow later tonight, followed by a secondary
cold frontal passage by Wednesday afternoon. A large area of
high pressure over the mid section of the country will then
slowly build in through the upcoming weekend. Low pressure could
impact the area early next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Areas of precip continue to remain disorganized, mainly well NW
of NYC and near/across eastern Long Island and SE coastal CT
attm. As a weak wave of low pressure developing along a warm
front to the south (near S DE/NJ early this afternoon) moves up
into the area and a sfc cold front approaches from the west,
chances for light rain should increase, with likely PoP well
inland and chance elsewhere. Temps will continue to slowly rise,
reaching 50 in parts of NE NJ and the mid/upper 40s along the
coast, with lower 40s inland.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
Chances for light rain will continue throughout into the first
half of tonight as the weak sfc wave along the warm front lifts
across Long Island this evening, followed quickly by a cold
front later tonight. Rain chances should be confined mostly to
ern Long Island and SE CT by midnight, with dry conditions
throughout before daybreak as winds shift NW.

Skies quickly clear daytime Wed, with a secondary cold frontal
passage expected by afternoon. Gusty NW flow in the morning
could briefly lull right ahead of this secondary passage, then
ramp up to 15-20 mph with gusts 30-35 mph in the afternoon. High
temps in the 40s to near 50 expected per blend of MOS and
adjusted model soundings, with deep mixing winning out initially
over CAA in the afternoon as far as temps are concerned.

Mostly clear/cold conditions expected Wed night, with gusty NW
flow. Since winds may not decouple if at all until late, sided
with the slightly less colder side of the MOS guidance for
lows, with 15-20 inland and 20-25 for NYC metro and the coast.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Not much has changed in the last 24 hours heading into the
upcoming weekend. Differences arise late in the period with
timing of shortwave energy in both the northern and southern
branches of the polar jet. Before then though, the northern
branch of the polar jet will make another brief appearance
across the northeast quarter of the nation.

Polar high pressure over the northern plains at the onset of the
period dives south and east and into the southern Mid Atlantic and
Tennessee Valley states by the weekend. At the same time, a series
of lows will pass well north of area across Canada. A N-NW flow
through Friday will then veer around to the W/SW over the weekend.

The coldest days of the week will be Thursday and Friday with highs
generally in the 30s with lows in the teens to lower 20s.
This is approaching 10 degrees below normal for this time of year.
Readings will climb back up into the 40s for the weekend with a
warmer southwest flow. A few 50 degrees readings across the NYC
metro are possible Sunday and Monday.

There is some uncertainty at the end of the forecast period as a
northern branch shortwave tracks across eastern Canada and another
in the southern branch emerges from the Southern Plains. The 00Z GFS
is much quicker and stronger with the energy in the northern branch,
sending height falls into the Northeast and a weak cold front
through the area Sunday night. This in turn builds a ridge on the
backside of the shortwave and impedes the progress of the southern
branch feature. The ECMWF and GGEM are in better agreement with the
timing of these features, slower and weaker with the northern
stream, and quicker with the southern stream. The latter of which
could bring some overrunning rains into the area as early as Monday
or as late as Wednesday depending upon the solution. For the time,
will continue with low chances for rain late Monday. Lots of time
for changes in what has been mainly a progressive southern branch
flow across the Lower 48 this winter.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
A warm front passage this evening will be followed by a cold front
moving across not too long thereafter. High pressure builds in late
tonight into Wednesday.

Light rain initially this afternoon to the east of NYC terminals.
Rain chances increase into early this evening, with rain
becoming likely across the interior. Rain this evening will
taper off east of NYC terminals near the start of the overnight
period with dry conditions returning to all terminals before
daybreak Wednesday. MVFR conditions continue into this
afternoon. Conditions are forecast to lower to IFR by early
evening, with local areas possibly remaining MVFR and having
more fluctuation between MVFR and IFR. Conditions return to VFR
late tonight.

Winds E around 10 kt initially, become more southerly late this
afternoon into early this evening, and SW-W mid to late this
evening. Some 15-20 kt gusts are possible before 21Z. With the
passage of a cold front winds become NW near 10 kt with gusts
15-20 kt late tonight.

 ...NY Metro Enhanced Aviation Weather Support...

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

KJFK TAF Comments: Low confidence in IFR conditions. It may be more
intermittent and shorter in duration than indicated in TAF.

KLGA TAF Comments: Low confidence in IFR conditions. It may be more
intermittent and shorter in duration than indicated in TAF.

KEWR TAF Comments: Low confidence in IFR conditions. It may be more
intermittent and shorter in duration than indicated in TAF.

KTEB TAF Comments: Low confidence in IFR conditions. It may be more
intermittent and shorter in duration than indicated in TAF.

KHPN TAF Comments: Moderate confidence in IFR conditions. Duration
of IFR may vary by a few hours compared to TAF.

KISP TAF Comments: Moderate confidence in IFR conditions. Duration
of IFR may vary by a few hours compared to TAF.

.OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...
.Wednesday...VFR. NW winds gusts near 25kt during day, diminishing
at night.
.Thursday-Sunday...VFR.

&&

.MARINE...
SCA continues on all ocean waters into daytime Wed, and has been
extended out east into Wed evening. SCA also issued for the
remaining waters for Wed afternoon.

Seas continue to build above wave guidance this afternoon
despite E-SE winds a little lower than initially fcst, and
should peak at 6-8 ft this afternoon into early evening. NW flow
after a secondary cold frontal passage should lead to winds
gusting to 25 kt on the near shore waters elsewhere.

Winds and seas should diminish Wed night, with sub-SCA
conditions then forecast into the weekend as a large area of
high pressure builds in from the mid section of the country.
NW-N winds Thursday through Friday will generally be 10 to 15 kt
on the ocean and 10 kt or less across the remaining waters.
Winds then veer to the SW over the weekend. Seas on the ocean
will generally be less than 5 ft.

&&

.HYDROLOGY...
No hydrologic impacts expected with only 1/3 of an inch of
liquid equivalent or less expected. Thereafter, no hydrologic
impacts expected through Monday.

&&

.EQUIPMENT...
NYC NOAA Weather Radio Station KWO35 (162.55 MHz) is still
operating at reduced power.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 6 PM EST Wednesday for ANZ350-353-
     355.

&&

$$
SYNOPSIS...Goodman/DW
NEAR TERM...Goodman
SHORT TERM...Goodman
LONG TERM...DW
AVIATION...JM
MARINE...Goodman/DW
HYDROLOGY...Goodman


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