discussion on 2024-04-19

000
FXUS61 KOKX 191953
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
353 PM EDT Fri Apr 19 2024

.SYNOPSIS...
-- Changed Discussion --A cold front moves across the region late tonight into early
Saturday, followed by a secondary dry cold front Saturday
evening. High pressure then builds into the beginning of the
week, but then gives way to a frontal system that will impact
the area for the middle of next week. High pressure returns at
the end the week.-- End Changed Discussion --

&&

.NEAR TERM /THROUGH SATURDAY/...
-- Changed Discussion --Surface ridging will continue to weaken this evening as a
cold front approaches from the west. An initial band of showers
ahead of the front across upstate NY and eastern PA will weaken
as it encounters the lingering ridging and some dry air. A few
sprinkles are possible as this activity weakens late this
afternoon and early evening, mainly west of the NYC metro. Most
CAMs indicate a relative min in precipitation from 00z to about
06z. Will continue to show a gradual increasing trend in PoPs
for the first half of tonight.

PoPs will steadily increase after 06z from west to east due
to an approaching jet streak over the Ohio Valley/Midwest.
Increasing upper divergence ahead of the jet will result in more
organized lift. There will also be a bit more organized thermal
forcing, especially along and east of the Hudson River
corridor. Showers should become widespread early Saturday
morning as a result and then gradually push east of the area by
midday as the cold front shifts offshore. Most the of rainfall
should be light although a few briefly moderate showers cannot
be ruled out. Amounts are lightest west of the city, around one
tenth or less. Along and east of the Hudson River Corridor
including the NYC metro, amounts range from around two to three
tenths.

Improving conditions are expected late morning into the afternoon
with the likelihood for some sunshine as clouds thin/diminish.
However, the associated shortwave will be swinging across New
England late Saturday afternoon and evening. Partly to at times
mostly cloudy conditions look probable, but this should be
enough to allow temperatures to rise into the lower and middle
60s with some upper 60s possible in the NYC metro. IF there is
less cloud cover than currently forecast, highs could end up a
few degrees warmer given a strengthening downslope westerly
flow. A secondary cold front quickly moves through in the early
evening with the aforementioned shortwave axis. For now will
just show a slight chance PoP for interior S CT closest to the
vort max which is supported by the latest CAMs.-- End Changed Discussion --

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
-- Changed Discussion --Surface high pressure centered over the central states will
slowly build towards the region Saturday night into Sunday.
Mostly clear skies are anticipated Saturday night with lows
falling into the 30s inland and Long Island Pine Barrens and
lower 40s closer to the coast.

A large upper level low will be developing over southeast
Canada Saturday night into Sunday. This will result in
troughing persisting over the eastern US early next week. A
wave of low pressure is progged to develop over the southeast
on Sunday along with another shortwave swinging across New
England. These features will likely bring middle and upper level
clouds on Sunday with partly to mostly cloudy skies and dry
conditions. Highs will be a few degrees below normal in the
upper 50s to around 60 degrees.-- End Changed Discussion --

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
-- Changed Discussion --The upper trough axis lifts out of the Northeast Sunday night
with a brief return to a more zonal flow across the northern
tier of the country. At the surface, weak high pressure builds
east into the area through Monday night. The next piece of
energy, located over the Northern Plains on Monday, will carve
out an upper trough across the Great Lakes on Ohio Valley states
Tuesday, and then on into the Northeast and Mid Atlantic states
on Wednesday. The associated frontal system will impact the
area Wednesday into Wednesday night with increasing chances of
showers during this time. At this time, there is little
instability advertised in the guidance, so will keep the mention
of thunder out of the forecast at this time. System looks
progressive with rainfall amounts expected to be under an inch
at this time. High pressure then closes out this week. There are
some differences in the global models with the frontal timing
and the interaction with northern branch energy, but impacts
still look minimal. Thus, stayed very close to a consensus
forecast. So all in all, a relatively benign period with no
hazardous weather expected.

Temperatures will generally be at or just below seasonable
levels with the exception of some milder air mid week in a
strengthening southerly flow ahead of the approaching frontal
system. Even then, it won`t be much higher than normal.-- End Changed Discussion --

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
High pressure will weaken this afternoon as a cold front
approaches from the west by tonight. The front will move
through late tonight into early daytime Saturday.

MVFR cigs had developed at the NYC metros and across parts of
Long Island on leading edge of flow turning SE. These initial
cigs shouldn`t last long, but widespread MVFR cigs should
return this evening and then lower to IFR close to midnight at
the NYC metros, then an hour or two later to the north and east.

Showers off to the west attm should dissipate as they approach
the Hudson Valley and NYC metro area, then showers with the
approaching cold front should arrive late tonight into Sat
morning. Some MVFR cigs should linger into the morning after
fropa, with improvement to VFR from around 14Z at the NYC
metros to around 16Z out east at KGON. NW-W flow after fropa
should be mostly under 10 kt, but could pick up with some gusts
15-20 kt close to 18Z from KTEB/KEWR north/west.

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

High confidence in winds. Unscheduled AMD possible for changing
flight categories through this evening.

OUTLOOK FOR 18Z SATURDAY THROUGH TUESDAY...

Saturday afternoon: VFR. W-WNW winds increasing to 15G20-25kt.

Saturday night: VFR. Secondary cold fropa early with winds
shifting NW 10-15G20kt.

Sunday: VFR. W winds G15-20kt in the afternoon/early evening
mainly NYC metros/coast.

Monday and Tuesday: VFR.

Wednesday: Showers becoming likely. S winds 10-15G20-25kt mainly
in the afternoon/evening, becoming NW at night.

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

&&

.MARINE...
-- Changed Discussion --SCA remains in effect for the ocean until 06z for seas around
5 ft. A cold front moves across the waters early Saturday
follow by a secondary cold front Saturday evening. High pressure
then builds Saturday night through Sunday. Winds and seas are
expected to remain below SCA levels from late tonight through
Sunday given a relatively weak pressure gradient.

High pressure should then keep conditions at sub-advisory
levels through at least Tuesday night. Conditions may build
back to SCA levels on Wednesday with the next low pressure and
associated cold front to approach.-- End Changed Discussion --


&&

.HYDROLOGY...
-- Changed Discussion --
No hydrologic impacts expected through next week.-- End Changed Discussion --

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 2 AM EDT Saturday for ANZ350-353-
     355.

&&

$$

SYNOPSIS...DS/DW
NEAR TERM...DS
SHORT TERM...DS
LONG TERM...DW
AVIATION...BG
MARINE...DS/DW
HYDROLOGY...DS/DW