okx-afd on 2024-04-25

000
FXUS61 KOKX 251934
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
334 PM EDT Thu Apr 25 2024

.SYNOPSIS...
-- Changed Discussion --Strong high pressure building in through tonight will remain
over the region into Saturday. The high will give way to an
approaching warm front Saturday night. A warm front lifts north
of the area Saturday night into Sunday morning followed by high
pressure through Monday. A cold front approaches Tuesday and
moves across the region Tuesday night. Another cold front may
pass through late Wednesday or next Thursday.-- End Changed Discussion --

.NEAR TERM /UNTIL 7 AM FRIDAY MORNING/...
-- Changed Discussion --Northern stream trough remains over northern New England/SE CT
tonight, with Canadian high pressure building in from the
northwest through tonight.

Synoptically aided SE breeze front will continue to push inland
through early evening, before weakening.

Ideal radiational cooling conds tonight with fresh Canadian
airmass, clear skies, and light winds.

Lows in the upper 20s to around freezing for interior of NE NJ,
LoHud, and S CT, and pine barrens of LI where freeze warnings
have been posted. Frost conditions for all but NYC/NJ metro and
immediate surroundings tonight with lows in the mid 30s. Lows
around 40 for NYC/NJ metro.-- End Changed Discussion --

.SHORT TERM /7 AM FRIDAY MORNING THROUGH SATURDAY/...
-- Changed Discussion --Northern stream shortwave trough gradually slides east on
Friday, with upper ridging building in from the west Fri Night
into Saturday. At the same time, good agreement in a vigorous
closed upper low over the northern plains on Friday shearing
into Ontario on Saturday.

At the surface, the center of Canadian high pressure builds
over the area Friday morning and sinks south of the region late
Friday into Saturday.

Unseasonably cool airmass remains over the region on Friday
with light northerly flow giving way to aggressive afternoon
sea breeze development once again. Despite plentiful sunshine
and deep mixing, 850 temps just below freezing will only have
temps topping in the upper 50s to around 60 (several degrees
below seasonable).

Another night of good radiational cooling conds Fri Night,
although with a slightly moderated and moistened airmass, temps
should be a few degrees warmer than tonight. Will likely have
temps dropping into the lower to mid 30s with frost conditions
across interior of NE NJ, LoHud, and S CT, and pine barrens of
LI.

Continued moderation of airmass on Saturday with strengthening
return flow around high pressure to the SE and approaching warm
front to the west. Strong sea breeze signature will likely push
maritime airmass well inland and keeping temps several degrees
below seasonable once again (upper 50s to around 60) for much
of the coastal plain. In addition, increasing high clouds
streaming in ahead of approaching warm front and over the top of
the ridge axis will likely filter sunshine in the afternoon.
Appears any light precip should stay west of the region during
the day though.-- End Changed Discussion --

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
-- Changed Discussion --Main story to start the long term will be anomalously strong ridging
making its way over the eastern US Sunday into Monday before
potentially breaking down Tuesday. A few shortwaves likely pass
across the northeast Tuesday night into Thursday. The modeling is in
good agreement through Monday on the larger scale pattern before
timing/amplitude differences arise Tuesday through the middle of
next week.

*Key Points*

*Mainly dry conditions expected with a few low chances of showers
both Saturday night/early Sunday and then again Tuesday into Tuesday
night.

*A warming trend is likely to begin on Sunday and continue into
Monday with temperatures potentially reaching 10-15 degrees above
normal Monday, especially away from the immediate coast.

*Temperatures remain above normal Tuesday through next Thursday.

A warm front lifts over the area Saturday night and should end up
north Sunday morning. Heights aloft are rising through this time
frame and lift is weak. A few showers are possible with the front,
especially across the interior Saturday night. The continuation of
the building ridge over the eastern states on Sunday will likely
result in at least partial clearing through the day. A SW flow
develops behind the passage of the warm front allowing temperatures
to warm significantly compared to recent days. There is a
significant amount of spread in high temperatures for Sunday,
especially for locations away from the immediate coast. For some of
the warmer locations the NBM deterministic actually falls below the
25th to 75th percentile of the ensemble. There should be enough
clearing along with building heights aloft and little onshore flow
influence for temperatures to end up on the higher side. Have
decided to blend in the NBM 50th percentile for now away from the
coast which yields highs middle to upper 70s. The 75th percentile of
the NBM indicates temperatures could reach or exceed 80 degrees.
Onshore flow over Long Island and southern CT likely holds
temperatures in the 60s with some locations potentially close to 70
degrees.

The ridge axis will be overhead on Monday. Strong subsidence will
likely lead to even warmer temperatures compared to Sunday. The NBM
deterministic is near the 25th percentile with much of the spread on
the warmer side of the warmer side of the ensemble. Have once again
blended in the NBM 50th percentile for the NYC metro, NE NJ, and
Lower Hudson Valley/interior SW CT. The flow is weak during the
first half of the day, but sea breezes should develop in the
afternoon. Forecast highs range from the lower to middle 80s in the
warmer spots to the upper 60s to middle 70s near the coast. High
temperatures spread only increases further on Tuesday. For example
at KEWR, the 25th percentile is 71 and 75th percentile is 87
degrees. Given that this is next Tuesday, have gone close to the NBM
deterministic for now (60s east and lower to middle 70s west). The
warmer highs in the ensemble spread could easily be realized away
from the coast if the front is slower and ridge does not break down
as quickly.

The aforementioned cold front swings through sometime late Tuesday
or Tuesday night. A few showers and potentially a thunderstorm could
accompany the frontal passage. The CSU MLP has been indicating a
very low probability for a severe thunderstorm with this front
during its last few cycles. Confidence is very low with any
convection at this time range. Confidence is also low in sensible
weather details for Wednesday and Thursday and have followed the NBM
deterministic.-- End Changed Discussion --

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
Strong high pressure will build in through the TAF period.

VFR. SSE winds this afternoon at 10 kt or less will become light
and variable overnight. Winds will then return out of the SE
late Friday morning into Friday afternoon.

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

No unscheduled AMD expected.

OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...

Friday: VFR.

Saturday and Sunday: Mainly VFR. Only slight chance of a shower Sat
night into early Sunday morning.

Monday: VFR.

Tuesday: MVFR or lower possible in afternoon showers and
possible thunderstorms.

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

.MARINE...
-- Changed Discussion --Winds and seas will remain below advisory levels through early
next week. Coastal jet development Sat aft could have marginal
SCA wind gusts (20-25kt) for ocean waters and nearshore around
the entrance to NY Harbor.

Warmer air moving over the colder ocean early next week could
develop fog, but it is much too early for any specific details
and timing and extent.-- End Changed Discussion --

.HYDROLOGY...
No hydrologic concerns through the middle of next week.

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --CT...Freeze Warning from 2 AM to 8 AM EDT Friday for CTZ005>008-012.
Frost Advisory from 2 AM to 8 AM EDT Friday for CTZ009>011.
NY...Freeze Warning from 2 AM to 8 AM EDT Friday for NYZ067>070-079-
081.
Frost Advisory from 2 AM to 8 AM EDT Friday for NYZ078-080.
NJ...Freeze Warning from 2 AM to 8 AM EDT Friday for NJZ002.
Frost Advisory from 2 AM to 8 AM EDT Friday for NJZ004-103-105-
107.
MARINE...None.-- End Changed Discussion --

SYNOPSIS...DS/NV
NEAR TERM...NV
SHORT TERM...NV
LONG TERM...DS
AVIATION...FEB
MARINE...DS/NV
HYDROLOGY...DS/NV