okx-afd on 2024-05-03

276
FXUS61 KOKX 031956
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
356 PM EDT Fri May 3 2024

.SYNOPSIS...
-- Changed Discussion --High pressure along the New England coast and into our area
will remain nearly stationary into Saturday. A cold front then
slowly approaches from the west on Sunday and moves across the
area Sunday night into Monday. The boundary likely stalls to our
south Monday afternoon through Tuesday before returning as a
warm front Wednesday. A series of frontal waves may impact the
area to end the week.-- End Changed Discussion --

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
-- Changed Discussion --A high amplitude upper ridge over the eastern third of the
country will be slow to translate east through the first half
this weekend. This will keep surface high pressure ridging down
along the New England coast and into our area. Expect a light
easterly flow to continue with varying amounts of cloud cover.
Satellite imagery shows a fair amount of high clouds moving
through the upper ridge axis. This could impact temperatures
somewhat depending on the opacity. Lows will generally be in
the mid to upper 40s, but around 50 for the NYC metro.-- End Changed Discussion --

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
-- Changed Discussion --Not much change during this time as the forecast area will
remain under an easterly flow at 10 mph or less. Varying amounts
of high clouds will filter through the upper ridge over the
area on Saturday, which works to the east Saturday night. Clouds
will lower and thicken Saturday night with some fog possible
toward daybreak Sunday. Warm advection rain on the backside of
the ridge, ahead of an approaching warm front, continues to
trend slower. Chances of rain Saturday night remain low and
mainly after midnight. Temperatures during this time will at or
just below normal.-- End Changed Discussion --

.LONG TERM /SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --*Key Points*

*An approaching front will bring rain Sunday into Sunday night,
which ends early Monday morning. Rainfall amounts average one
quarter to one half inch.

*The front stalls to our south early next week with limited chances
for showers through Tuesday.

*Unsettled conditions are likely Wednesday through next Friday,
although not a wash out. Several frontal waves are possible, which
may bring periods of showers, but timing is uncertain.

*Below normal temperatures Sunday should trend back above normal
next week. Timing of the potential precip could impact temperatures
late in the week.

A shortwave associated with a larger upper low over Central Canada
will try to break down the highly amplified ridging over the east
coast to start the long term. The guidance has continued to show a
slower trend to this process with the associated frontal system not
moving through the area until Sunday night or early Monday. Rain
associated with the front should start in the morning west of the
NYC metro and then slowly spread eastward through the afternoon.
This continues to look like mainly an overrunning rainfall with
little to no elevated instability. Average amounts range from around
one quarter to one half inch.

The shortwave axis will push offshore later Monday with the front
stalled to our south and west. Another highly amplified ridge builds
across the Great Lakes in response to a large upper low over the
Northern Plains and Northern Rockies. There are conflicting signals
in the guidance for whether or not energy will traverse underneath
the ridge towards the area Monday night. This potential energy would
interact with the stalled front to bring another chance of rain.
However, some of the global guidance weakens the energy with the
height field becoming suppressed over New England in response to an
upper low over the Maritimes. A weak high pressure should build
towards New England which should keep any precip, if it were to
develop, mainly near the coast closer to the stalled front. Have
used the NBM for PoPs with just a low chance near the coast Monday
night.

A piece of the ridge builds overhead on Tuesday, so this should end
up being a mainly dry day. The next forecast challenge will be for
Wednesday through the end of the week. The stationary front to our
south and west should begin lifting back north as a warm front on
Wednesday. The parent low will be associated with the upper low over
the Northern Rockies and Northern Plains, but there may be a few
waves along the warm front. One of these may be enough to initiate
some convection Wednesday afternoon or evening. The upper low then
slowly moves east towards the Great Lakes to end the week. Several
frontal waves may move across or just south the area keeping
conditions unsettled. Timing of these waves is highly uncertain
given a late Day 5 through Day 7 forecast, so have capped PoPs off
at high chance for now.

Sunday will be cool with rain and temperatures in the middle to
upper 50s. Conditions should begin rising back above normal next
week with temperatures in the 70s most afternoons away from the
immediate coastline. Have followed the NBM deterministic, but it
should be noted that there is a fair amount of spread in the
guidance, especially later in the week due to the potential precip.-- End Changed Discussion --

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --High pressure remains along the New England coast and into our
area through Saturday.

VFR to start. Cigs may fall once again into late tonight into
Saturday morning with potential stratus development, though
confidence is too low to prevail at this time. However, added a
TEMPO group for this possibility from 08Z-12Z Saturday.

An E/SE flow with speeds around 10 kt or less will shift to the
E tonight for the city terminals, and become light and variable
for the outlying terminals. An occasional gust to around 20 kt
is possible into the early evening hours. SE winds on Saturday
with speeds at or below 10 kt.

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

There is uncertainty with the development of MVFR or lower clouds
tonight. Best timing for this is between 08Z-12Z.

OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY...

Saturday: Mainly VFR. Low prob of patchy early AM MVFR stratus.
Slight chance of showers and MVFR conditions in the afternoon,
increasing chances overnight.

Sunday...Likely showers, with MVFR or lower conditions. ESE winds
G15-20kt.

Monday...VFR.

Tuesday... Mainly VFR. Chance of MVFR showers.

Wednesday...MVFR or lower with a chance of showers.

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

.MARINE...
-- Changed Discussion --Sub-SCA conditions are forecast to start the weekend with high
pressure along the New England coast maintaining an easterly
flow across the waters. Winds will generally be around 10 kt.

Winds and seas should remain below SCA criteria Sunday the middle of
next week with a weak pressure gradient in place. There may be an
increase in winds closer to 20 kt and seas building to around 4 ft,
but conditions are expected to remain below SCA levels.-- End Changed Discussion --

.HYDROLOGY...
-- Changed Discussion --
There are currently no hydrologic concerns through next week.-- End Changed Discussion --

&&Weak high pressure builds in through the day, then retreats to the
Canadian Maritimes Saturday.

Continued improvement in cigs expected through the afternoon with
VFR expected by 19Z for most, if not all terminals. Cigs may fall
once again into late tonight into Saturday morning with potential
stratus development, though confidence is too low to prevail at this
time. However, added a TEMPO group for this possibility from 08Z-12Z
Saturday.

An E/SE flow with speeds around 10 kt or less much of the day will
shift to the E tonight for the city terminals, and become light and
variable for the outlying terminals. An occasional gust to around 20
kt is possible this afternoon into the early evening hours. SE on
Saturday with speeds at or below 10 kt.