000
FXUS61 KOKX 191950
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
350 PM EDT Fri May 19 2023
.SYNOPSIS...
-- Changed Discussion --
Low pressure approaches the area late tonight and moves through
on Saturday. A cold front then quickly follows Saturday evening.
Behind a cold frontal passage on Sunday, high pressure builds
into the area on Monday and remains in place through the end of
the week.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
-- Changed Discussion --
Clouds increase tonight ahead of a weak low pressure center that`ll
be taking shape off the coast of North Carolina. A trough extends
north from the center towards us and will be where some moisture
convergence occurs. The moisture will be shallow however, so any
showers that develop should be on the light to moderate side. The
cloud cover should hold temperatures in the 50s through the night in
most spots, but closer to 60 in the city.-- End Changed Discussion --
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
-- Changed Discussion --
The low pressure center continues to head toward us, passing through
during the afternoon to evening hours. Rain becomes likely from
generally south to north as the morning progresses. Lift and
moisture increase late morning into the afternoon as a low level jet
enters and passes through the eastern half of the forecast area.
This will be beginning of when moderate to briefly heavy rainfall
may occur, with this threat lasting into the evening. A trailing
cold front then passes through during the evening with lowering
chances of rain as it traverses east. A little more CAPE is progged
as compared to 24 hours ago, so will maintain the mention of
isolated thunder over eastern LI and SE CT for late afternoon into
early evening. As for rainfall amounts, High-res CAMs and NBM favor
a more westerly axis of heaviest rainfall for the entire event,
while the global models favor farther east - closer to eastern LI
and SE CT. After some collaboration, have decided to stick very
close to WPC guidance, which appears to lean more toward a westerly
axis. See the hydrology section below for more details.-- End Changed Discussion --
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --
Behind the primary cold front, a more subtle and weaker cold front
moves through the area on Sunday with clearing skies and drying
conditions. The upper-level trough remains overhead through the
beginning of the week as surface high pressure builds into the area
from the northwest. Weak mid-level energy moves through Monday night
into Tuesday but will remain dry.
Surface high pressure remains in place by midweek with an upper-
level ridge building over the area through the end of the week. A
dissipating cold front attempts to approach the area from the north
into Wednesday night and Thursday but looks to remain weak enough to
not produce any precipitation. There is some signaling of a mid-
level blocking pattern to develop over the Eastern US by the end of
the week which may continue to allow high pressure to dominate the
Northeast.
Temperatures during the extended period look to remain at or above
average each day with highs generally in the 70s each day. Easterly
flow on Tuesday will result in slightly cooler highs than much of
the rest of the week, generally only climbing into the middle to
upper 60s. Lows will follow the same general pattern with
temperatures dropping into the 50s each night with the exception of
Monday and Tuesday night where lows may drop into the 40s for much
of the area with the exception of the NYC Metro.-- End Changed Discussion --
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
High pressure east of Long Island continues to move east through
this evening. A weak wave of low pressure approaches from the south
and impacts the area Saturday.
VFR through late this evening at all terminals. MVFR ceilings move
in after 05Z Saturday and then drop to IFR around 09Z. The best
chance for high end LIFR cigs look to be between 12 and 18Z Saturday
and have included this in a prevailing group. Cigs then slowly
improve thereafter, becoming IFR around 18Z and MVFR around 22Z.
-SHRA could bring MVFR visby as early as 09z and then more steady
moderate rain is expected by 12z, with MVFR/IFR vsby.
A S/SE flow 10-15KT continues this evening. Gusts up to around 20-25
kt likely, ending toward sunset, with winds shifting more to the SE,
then E toward daybreak Saturday. Winds remain E through Saturday
afternoon and then become more S at 18Z.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
No unscheduled amendments are expected through this evening.
Gusts in this afternoon may be more occasional, and may end 1 to 2
hours earlier than is forecast.
Amendments are possible as cigs lower tonight. Lowering to IFR may
happen an hour or two earlier. Increasing back up to MVFR Saturday
afternoon may happen an hour or two later.
OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY...
Saturday Afternoon: IFR to LIFR with showers. Possibly improving to
MVFR west late in the day. An isolated TSTM possible for eastern
terminals, with a low chance for LLWS at 2 kft for these areas as
well.
Sunday through Wednesday: VFR.
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 prevail tonight with a SE flow weakening to under
10 kt overnight. A weak low pressure center will pass through the
waters on Saturday afternoon into evening. While onshore winds might
not become particularly strong during the day into the night, a SE
swell should help push wave heights on the ocean above 5 ft during
the day and continue through the night. Gusts to 25 kt are anticipated
east of Fire Island Inlet. Looks like an inversion will be too
strong to mix down gale force gusts. SCA for the ocean starting
late Sat morning and continuing through Sat night for now.
SCA conditions likely persist on the ocean during the day on Sunday
with wave heights 5-7 feet. Conditions likely drop below SCA for all
waters by Sunday night. Some gusts may approach 25 kt on the ocean
again on Monday afternoon with seas possibly briefly building to
near 5 feet. Sub-SCA conditions are once again expected by Monday
night and through the middle of the week.-- End Changed Discussion --
&&
.HYDROLOGY...
-- Changed Discussion --
Rain amounts from early Saturday morning through Saturday evening
are expected to range as little as a quarter to half inch well NW of
NYC to as much as an inch to two inches east of Orange and Western
Passaic Counties. Highest amounts are anticipated generally over LI
and southern CT, with chances of even higher rainfall, particularly
over southern CT. Although flash flooding is not completely out of
the question, confidence is low in any occurrence of this - largely
due to antecedent dry conditions as well as ongoing disagreement
among the models regarding the axis of the heaviest rainfall. There
would be at least a little more concern for flash flooding if there
was better agreement that the heavier rainfall would occur over NYC
into NE NJ where flash flood thresholds are typically easier to
meet, and/or if models continue to trend wetter overall. With this
said, there is at least moderate confidence that rainfall would be
heaviest from late morning into early evening, and any flooding
would more likely be of the minor/nuisance type.
No hydrologic concerns are expected from Sunday through the end
of next week.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 11 AM Saturday to 6 AM EDT Sunday
for ANZ350-353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JC/MW
NEAR TERM...JC
SHORT TERM...JC
LONG TERM...MW
AVIATION...JT
MARINE...JC/MW
HYDROLOGY...JC/MW