discussion on 2024-04-12

000
FXUS61 KOKX 121759
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
159 PM EDT Fri Apr 12 2024

.SYNOPSIS...
A cold front swings through for the first half of today as low
pressure lifts north into Eastern Canada. A series of surface
troughs will pivot through during the first half of the weekend.
A high pressure ridge briefly works in Saturday night into
Sunday morning. A weak wave of low pressure will drag a warm
front followed by a cold front through Sunday night into Monday
morning. High pressure takes over Monday, potentially followed
by a warm front front moving in late Tuesday into Wednesday.

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Another round of showers is moving through western portions of
the forecast area. This is in association with a secondary cold
front or surface trough. There may be an isolated thunderstorm
that develops, with dew points in the upper 50s to lower 60s in
this area, and some mixed layer CAPE in the 100-500 J/kg earlier.
However, models show this weakening as it heads east and lifts
north, and mixed layer CAPE is decreasing. Ahead of this area
of showers, dense fog had developed across New York City,
central and western Long Island, and southwest coastal
Connecticut. Visibility is improving in the city currently, and
expect this to continue through the morning as showers help to
mix out the fog. Any dense fog should dissipate by noon or
prior.

The cold front pushes through eastern parts of the CWA by mid
to late morning, and thus any organized rain should be mainly
east and north by then. The winds will be rather gusty, but
decrease some from their peak earlier. For a 3 to 4 hour period
the winds relax some, but then pick up for the afternoon as a
surface trough pivots through. Gusts up to 35 mph are expected
after the trough passage as heights lower and more ideal mixing
takes place across the area with steeper lapse rates. With
spokes of energy wrapping in behind the departing low showers
along with increasing frictional flow and cyclonic curvature
look for some showers to pivot through. With the profile drying
out in the lower levels any showers and drops that can make it
down to the ground would have some higher gusts perhaps as an
inverted V type profile attempts to set up. BUFKIT also hints at
a little mid level CAPE, thus cannot rule out some low end low
topped quasi-convective clusters. However, any activity would be
isolated to widely scattered and mainly over western and
northern sections. Despite a gusty SW flow providing cool air
advection, temperatures will average above normal today with
mainly lower and middle 60s for daytime maxes under varying
amounts of cloud cover. Some upper 50s are more likely for
eastern coastal sections.

The strong SW flow continues despite the loss of daytime heating
tonight. The winds become more westerly gradually with time during
the night, and even more so with the passage of another surface
trough into early Saturday morning with falling dew points. Night
time minimum temperatures will fall into the middle 40s to around 50
in most places with the wind and variably cloudy skies preventing
any radiational cooling.

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/...
Spokes of energy aloft along with the passage of an additional
surface trough will reinforce drier air at the surface and
eventually cooler air into the start of the weekend. The main upper
level trough pivots through early Saturday morning. With the
instability and cooler air aloft expect a self destruct sunshine
mechanism, with any breaks of sun and surface heating quickly
leading to a good deal of clouds with a strato-cumulus combination at
around 4 kft. Low end chance to slight chance PoPs for NW sections,
otherwise expect mainly dry and blustery conditions. The winds will
gust to around 35 mph across the CWA with good mixing with cold pool
aloft and pressure gradient still in place on the back side of low
pressure in Eastern Canada. Any showers may contain brief gusty
winds, but much of the time it should remain dry with more of a
classic V inverted profile. Much of the shower activity likely won`t
make it to the ground with more virga, than actual shower activity
perhaps. Temperatures for Saturday will be cooler as 850 mb temps
will be a bit below freezing. Temperatures will likely remain in the
50s all day across the entire CWA.

For Saturday night after the last surface trough passage the
pressure gradient will eventually weaken as low pressure gets well
north into Eastern Canada. So expect the winds to diminish into the
late evening and overnight hours. The winds will not completely shut
off, but most locations will have gusts end as the night progresses.
With less in the way of cloud cover look for temperatures to be
cooler, with night time lows mainly in the lower and middle 40s.

For Sunday the upper level flow becomes quasi-zonal with a high
pressure ridge at the surface nosing in from the south. The day
should be primarily dry, but clouds do increase in advance of a
frontal system to the west and north. The front will be moisture
starved, thus only chance to slight chance PoPs getting later in the
day and mainly across the interior. The winds will be out of the SW
ahead of the boundary, thus temperatures should get a bit warmer for
later in the weekend as most places get back into the 60s, with
perhaps portions of NE New Jersey pushing 70 as cloud cover may hold
off long enough during the day.

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Chance PoPs preceding a cold front for Sunday night with a
chance of showers, along with perhaps some isolated thunder
with some elevated instability being indicated by NWP guidance.
A due north cold front will clear clouds and precip Monday
morning. The upper-level pattern remains zonal through Monday
before a strong ridge builds Tuesday into Wednesday. This will
lead to sunnier weather and temperatures warming into the
mid-70s to upper-60s, supported by warm air advection aloft.

The ridge remains in place on Tuesday, though a strong upper-level
jet develops aloft with a warm front placing itself over the area
from a low in the northern Great Plains/Western Great Lakes. These
will act together to increase cloud cover through the day on
Tuesday, but expected warmer temperatures to remain due to warm air
advection aloft. This warm front which eventually becomes a stalled
boundary will lead to rain chances Tuesday night into Wednesday.

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --Strong low pressure near the eastern Great Lakes will lift
slowly north cross eastern Canada through the TAF period.

Improvement to MVFR and then MVFR/VFR is expected this
afternoon with the wind flow becoming more westerly and allowing
some marginally drier air to push in from the west. Spotty
showers are possible but limited impacts at the terminals. On
Saturday, low end VFR expected in stratocumulus cloud
cover/ceilings. Spotty showers still possible Saturday mainly NW
and W of the city terminals.

S-SW 15-25 kt winds with gusts 25-35kt becoming SW-W this
afternoon and continuing into Saturday. Winds mainly W at the
same speeds on Saturday gradually becoming W-NW.

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

Amendments likely for timing of improving categories and wind
gusts.

OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY...

18Z Saturday: Chance of showers mainly NW of the NYC metros,
mainly VFR. W-NW winds G25-35kt.

Sunday: Mainly VFR. Chance of MVFR and showers in the afternoon.
SW-W winds G20-25kt.

Mon through Wed: Mainly VFR. Slight chc of MVFR late Wed.

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

.MARINE...
A statement for marine dense fog that was issued earlier has
expired. Conditions are starting to improve across the waters
around New York City, and this is expected to continue through
the rest of the morning. However, patchy dense fog may still
limit visibility to 1 nm or less at times until noon.

Seas will be 10 to 15 ft out on the ocean today as gale force wind
gusts give way to small craft wind gusts from west to east during
the course of this afternoon and early this evening on a S to SW
wind. Small craft conditions will linger through Saturday with a W
wind with gusts mainly 25 to 30 kt, with occasional gusts to gale
force out on the ocean. Ocean seas during this time will settle
closer to 7 to 8 feet. More marginal small craft conditions are
anticipated across much of the waters into Saturday night. Sub-SCA
conditions are expected for most of Sunday with ocean seas mainly
around 4 ft, with ocean seas get nudged back up by Sunday evening as
a SW flow increases out ahead of a cold front. Sub small craft
conditions are then likely to end by Monday evening with lighter
winds and lowering seas into Tuesday.

.HYDROLOGY...
No hydrologic concerns exist throughout the forecast period.

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --CT...None.
NY...None.
NJ...None.
MARINE...Gale Warning until 4 PM EDT this afternoon for ANZ331-332-340-
345.
Small Craft Advisory until 6 AM EDT Saturday for ANZ335-338.
Gale Warning until 6 PM EDT this evening for ANZ350-353-355.-- End Changed Discussion --

SYNOPSIS...JE/BR
NEAR TERM...JE/JP
SHORT TERM...JE
LONG TERM...BR
AVIATION...IRD
MARINE...JE/JP/BR
HYDROLOGY...JE