okx-afd on 2024-06-22

481
FXUS61 KOKX 230041
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
841 PM EDT Sat Jun 22 2024

.SYNOPSIS...
A stationary boundary stays north of the area through tonight, and
then should begin to lift further north Sunday. A cold front
approaches Sunday night and moves through early Monday with high
pressure to follow into Tuesday. A cold front passes through
late Wednesday night into Thursday. High pressure will then
return for Thursday night into Friday.

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
-- Changed Discussion --Isold-sct showers and thunderstorms will be around tngt with
instability and anomalous humidity in place. Frontal boundary
stays locked up north of the area, but close enough to have some
forcing impacts, especially across northernmost and
northeastern portions of the area. CAMs have had some
inconsistencies around whether convection lingers or re-fires up
during a portion of the night. Bulk shear should be no more
25-30 kt so not conducive to organized convection, however with
multiple weak boundaries around and a very humid air mass where
it does not take much to initiate or re-fire and some
interaction with any outflow could keep thing going some. It
will be a rather warm and muggy night. Also, like last night
where rain occurs causing a wet ground there very well may be
patches of fog in places. Don`t have this in the forecast as
synoptic flow may be a bit stronger than the previous night and
may preclude this, but this will need to be monitored.

Lows overnight remain well above normal with dew point readings
hovering around 70. Therefore no meaningful relief tonight as lows
will range from around 70 across a few interior and eastern coastal
sections, to the upper 70s across the NYC and portions of the NE NJ
metro.-- End Changed Discussion --

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
-- Changed Discussion --The region should get even more into the warm sector on Sunday as
the warm front lifts further to the north. In terms of this stretch
of heat and humidity, this should be the most uncomfortable day
widespread across the area. Therefore continue heat headlines for
one more day, and added So. Nassau, So. New Haven, and So
Middlesex as temps just away from the immediate shore should be
able to reach 95 heat index criteria for 2 consecutive days
this weekend, thus the northern portions of these southern zones
are close enough to warrant the advisory. Only far eastern
coastal sections look to remain just below heat adv criteria on
Sunday.

The chances for more widespread and more organized convection
increase into Sunday afternoon and evening despite the fact that
storm coverage with convective allowing models isn`t all that
impressive. There should be better priming of the overall
environment as height falls in increase for the afternoon and
evening. The winds increase aloft, thus better bulk shear should
lead to more organized convection with the primary threat from any
storms being strong damaging wind gusts, with hail and an isolated
tornado possible but on the lower end of the threat scale. Storm
mode will likely be multicell, with a more linear / broken linear
mode possible into the evening as forcing increases. A mixed mode of
cluster / supercell cannot be ruled out further north across the
CWA. Hodograph curvature carves out more storm relative helicity
further north on Sunday. SPC has a Slight risk of severe storms for
a little more than half the area, with a marginal risk further
southeast across the area. Heavy downpours and lightning will be a
concern as well with any storms. With the faster flow aloft storms
should move along as any localized flash flood threat would be more
from repeat / training storms as individual cells should move faster
compared to the previous day. With the very high moisture
environment with PWATs likely just above 2 inches for much of the
area and a warm cloud layer easily above 11 kft instantaneous
rainfall rates could be rather high, and a potential issue for the
more urban environments in terms of localized flash flooding.
Overall the flash flood threat coverage wise appears limited due to
the faster nature of the storms, but one or two isolated cases
remain a concern. For more on potential hydrologic impacts see the
Hydrology section.

There is still a good deal of uncertainty for the overnight late
Sunday night into early Monday morning. There will be a pre-frontal
trough lingering which may serve as a focus for additional
convection towards the middle of the night. How much any previous
convection has worked over the storm environment will be the
determinant as to how much convection can occur during the night.
Getting towards early Monday morning the cold front starts to work
into western portions of the area. With the humid airmass still in
place look for widespread 70s for the low temperatures.

During the day Monday with the cold front getting to the east by mid
to late morning look for a drier N to NW flow. There should still be
a fair amount of cumulus as the cooler air aloft should be in place
with the upper level trough axis lagging behind a bit. Dew point
readings towards afternoon should get into the lower 60s, and may
even lower a bit more into the upper 50s or thereabout with
potentially more mixing due to downsloping. It will still be a very
warm day, just not as oppressive and heat headlines not anticipated.
With the upper level trough axis still lagging behind low end chance
PoPs seems prudent with a shower or thundershower possibility
through the afternoon. Temperatures in most places should top out
well into the 80s in most places due to a land based wind trajectory
out of the W and NW.-- End Changed Discussion --

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Key Points:

* Temperatures will remain near to just above normal for much of the
extended period.

* A slow moving frontal system could bring locally heavy rainfall
from late day Wednesday into Thursday.

There has not been much change to the thinking with the extended
forecast for this update, and followed the National Blend of Models
closely. Shortwave ridging on Tuesday gives way to a more zonal flow
by Wednesday into Thursday. A shortwave trough passes north of the
area on Thursday followed by weak ridging again into next weekend.
Much of the week looks to remain dry, save for a frontal system that
approaches from the west late Wednesday night into Thursday. Modeled
PWATS of close to 2" along with a weak steering flow aloft would
increase the chances of excessive rainfall for the area as the front
passes through the area. Model thermodynamic profiles also look
favorable for thunderstorm development; though this may be somewhat
limited given the nighttime approach of the system. The front passes
Thursday, with a return to drier conditions under high pressure and
westerly flow to end the week.

High temperatures on Wednesday look to be near 90F across the urban
corridor of NYC and NJ and upper 80s elsewhere. With dewpoints in
the mid to upper 60s, this will yield heat indices in the mid to
upper 90s across the hottest locations. Thereafter, the front
passes through and Thursday/Friday are a bit cooler, but still above
average, in the mid to upper 80s.

Dry weather returns Friday as another high builds into the region.

.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --High pressure remains across the Western Atlantic as a nearly
stationary front lingers north of the region.

Mainly VFR this eve, however sct shwrs and tstms will produce
mvfr or lower where they occur. The convection generally
dissipates everywhere by 3Z or so, although cannot rule out at
least isold tstms overnight. Stratus and fog development likely
late once again at some terminals, but low confidence in this at
NYC terminals and have omitted for now. Conditions improve by
late Sunday morning.

S or SW flow tngt with speeds generally at or under 10 kt.
Strong and gusty winds will be possible in and near tstms.
Strengthening flow on Sunday, increasing to near 15G25kt by
afternoon. Additional convection is likely in the afternoon or
early evening.

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

Cluster of tstms will impact the arpts thru 3Z. Tempo for EWR,
JFK and TEB. May need to include LGA based on trends.

Timing of convection on Sunday could be off by a couple hours.

MVFR or lower conditions possible early Sunday AM if low stratus or
fog is able to develop.

OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY...

Sunday night: Showers and thunderstorms likely with MVFR
conditions. S-SW wind gusts 20-25 kt along the coast.

Monday: MVFR with a chance of showers and thunderstorms.

Tuesday: VFR.

Wednesday: Mainly VFR. A chance of showers and thunderstorms in the
afternoon and at night, with MVFR or lower possible.

Thursday: MVFR or lower possible early.

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

.MARINE...
-- Changed Discussion --SCA on the ocean tngt for seas, and blw criteria elsewhere.
By early afternoon Sunday small craft conditions begin to
develop for a good portion of the near-shore waters, with
perhaps the exception of NY Harbor with gusts 25, to even 30 kts
further east. Ocean seas approach 8 ft late Sunday and Sunday
night. A cold front approaches Monday night with gusts falling
below small craft criteria on the nearshore waters, but seas and
gusts slower to subside on the ocean waters. Towards late
Monday afternoon and evening seas should eventually subside
enough for sub small craft conditions to return to the ocean
waters.

Winds and seas across all the waters remain below advisory levels
Tuesday and Tuesday night. Increasing southerly winds on Wednesday
and Wednesday night will allow for conditions on the oceans to
approach SCA conditions.-- End Changed Discussion --

.HYDROLOGY...
WPC has a marginal risk of excessive rainfall for most of the area,
with a Slight risk across a good portion of CT into this evening. A
marginal risk will continue for mainly north and northwest interior
portions of the area for Sunday and Sunday night. With a very humid
airmass in place any stronger storms could produce heavy rain with
isolated local instances of up to a few inches possible in a short
time.

There is a chance for locally heavy rain from late day Wednesday
afternoon into Wednesday night with a front moving through the
region.

.TIDES/COASTAL FLOODING...
There will be a high rip current risk for both Sunday and Monday for
all ocean beaches with higher wave energy approaching the shoreline
with a S to SW wind wave on Sunday. The winds becoming more offshore
on Monday, but with the high risk continuing.

.CLIMATE...
Here are current record high temperatures for Sunday...

Sunday, June 23

NYC: 96(1888)
LGA: 95(1965)
JFK: 94(2010)
EWR: 97(1965)
ISP: 91(1999)
BDR: 91(2010)

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --CT...Heat Advisory until 8 PM EDT Sunday for CTZ005>011.
NY...Heat Advisory until 8 PM EDT Sunday for NYZ067>075-078-176>179.
High Risk for Rip Currents from 6 AM EDT Sunday through Monday
evening for NYZ075-080-081-178-179.
NJ...Heat Advisory until 8 PM EDT Sunday for NJZ002-004-006-103>108.
MARINE...Small Craft Advisory from noon Sunday to midnight EDT Sunday
night for ANZ331-332-335-340-345.
Small Craft Advisory until 6 AM EDT Monday for ANZ350-353-355.-- End Changed Discussion --

SYNOPSIS...JE/DBR
NEAR TERM...JMC/JE
SHORT TERM...JE
LONG TERM...DBR
AVIATION...JMC/DR
MARINE...JMC/JE/DBR
HYDROLOGY...JE/DBR
TIDES/COASTAL FLOODING...
CLIMATE...