136
FXUS61 KOKX 131819
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
219 PM EDT Sat Jul 13 2024

.SYNOPSIS...
A frontal boundary drifts east across the area today and washes out
just southeast of the area tonight. High pressure returns
Sunday with a thermal trough setting up over the region Monday
and Tuesday. A cold front then approaches from the west on
Wednesday, moving offshore Thursday. High pressure may return on
Friday.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
The flood watch has been cancelled. The heaviest rain has moved
out of the watch area. While some showers are expected the rest
of the morning, widespread heavy rain and flooding is not
anticipated. Minor urban flooding is the main concern if any
heavy rain develops in NYC, NE NJ, and Lower Hudson Valley.
Further east, an area of heavy rain continues to progress
quickly across southeast CT. Flash flood guidance is higher here
and the progressive nature will prevent anything more than minor
flooding. There have not been many lightning strikes this
morning, but a rumble of thunder cannot be ruled out.

Any lingering shower activity should be located east of the
Hudson River and could just be across Long Island and southeast
CT. The frontal boundary and axis of deep tropical moisture will
shift offshore as the afternoon progresses, so coverage should
diminish towards evening. An isolated shower/storm cannot be
ruled out well NW of the city as instability builds due to
afternoon sunshine.

Muggy tonight, but at least dewpoints won`t be as high as they
have been for the past couple of nights as winds shift NW-W
overnight.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
Weak high pressure will be in control during Sunday. Some global
models and CAMs hint at a chance of an afternoon shower or
thunderstorm over western areas as sufficient CAPE might combine
with some upward forcing from a subtle shortwave. Have therefore
included a slight chance of a thunderstorm. Thinking is that any
convective debris clouds that would occur would arrive late enough
in the day to not have too much of a factor on high temperatures.
Models continue to show 850mb temps at mostly 17-19C during the
afternoon - highest over western zones. Highs in the upper 80s to
lower 90s for the most part. Given boundary layer dewpoints and a W-
SW low level flow, surface dewpoints should be able to mix out a
little during peak heating outside of any seabreeze/onshore wind.
NBM dewpoints still looked too high, so a blend of NBM, CONSALL and
superblend was used in most spots.

Models show more disagreement regarding 850mb temps for Monday,
possibly owing to the timing of a potential shortwave headed our way
that would help trigger some afternoon showers and thunderstorms
with plenty of CAPE in place. Temps at this level would otherwise
probably be around 20C. Have gone with NBM for highs, but it might
be a couple degrees too low, especially if there`s no interference
from convective cloud cover. Regardless, it appears that there will
be more areas that reach heat indices of at least 95 degrees.

Heat advisories have now been posted in areas where widespread heat
indices of at least 95 degrees will more likely occur for both
Sunday and Monday. This includes NYC, Nassau County, and the urban
corridor of NE NJ.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
The heat continues into Tuesday with another shortwave potentially
triggering afternoon/evening showers and thunderstorms. 850mb temps
climb even higher, reaching the low 20s C, with ambient temperatures
possibly reaching 100 in spots across NE NJ. Highs in the 90s
elsewhere. A good portion of the forecast area could see heat
indices reaching 100, and it is not out of the question for the heat
index to touch 105F in the urban NE NJ corridor.

A more amplified and deeper trough is likely to approach next
Wednesday. This will send a cold front into the area. Ahead of the
front, temperatures should once again reach the upper 80s and lower
90s. Dew points could end up slightly higher compared to Monday and
Tuesday, so heat indices peak in the middle to upper 90s, especially
away from the immediate coast and far northern interior.

A widespread convective event remains possible Wednesday
afternoon/evening into Wednesday night. Still some spread in global
ensembles, but it continues to look like the front will help usher
in a drier and more seasonable regime behind it late next week.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
A frontal boundary dissipates as it continues to slowly move
east going into tonight. High pressure returns for Sunday.

More improvement to VFR with only some isolated MVFR this
afternoon as most rain showers have shifted east of the region
with just a few showers near KISP and KGON before 19Z.

VFR returns for all terminals by late this afternoon into early
this evening. However, low stratus and fog forming will likely
work its way west late tonight into Sunday morning, which are
forecast to bring MVFR to IFR conditions for KGON and KISP. KSWF
is also forecast to have some patchy fog with MVFR overnight.
KHPN and KBDR could also have some low stratus and fog
development and to a lesser chance for the NYC terminals.
Otherwise, VFR conditions are forecast for the rest of the TAF
period.

Winds overall will be southerly near 5 to 10 kts on average for
this afternoon into this evening. Winds lower to near 5 kts
tonight into Sunday with wind direction becoming variable once
again before returning to a more SW flow on Sunday.

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

Wind direction uncertainty this afternoon. SE winds could arrive
1-2 hours earlier than forecast at KEWR. Southerly flow starting
at KLGA this afternoon may be off by 1-2 hours.

A low chance of MVFR to IFR overnight into Sunday morning.

OUTLOOK FOR 18Z SUNDAY THROUGH WEDNESDAY...

Sunday: VFR.

Monday through Wednesday: Mainly VFR. A chance of afternoon into
early evening showers and thunderstorms with MVFR possible at
times. SW wind gusts 15-20 kt afternoon into early evening on
Tuesday and Wednesday.

Thursday: A chance of showers and thunderstorms with MVFR
possible.

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

&&

.MARINE...
A lingering swell is keeping ocean waves 4-5 ft this morning
east of Fire Island Inlet. Have dropped the SCA west of there
as seas are below 4 ft. May be able to cancel the rest of the
SCA late this morning or early this afternoon. For the non-
ocean waters, winds and seas remain below advisory levels.

Winds and seas largely remain below SCA criteria tonight through the
middle of next week. Ocean seas may begin to approach 5 ft late
Wednesday ahead of an approaching front.

&&

.HYDROLOGY...
Locally heavy downpours remain possible into this afternoon,
mainly across Long Island and southeast CT. Minor urban/poor
drainage flooding are anticipated for any impacts.

Given an abundantly moist air mass in place, any thunderstorms that
develop early to mid next week will have the potential to produce
locally heavy downpours that result in nuisance flooding,
particularly in urban and poor drainage areas.

&&

.TIDES/COASTAL FLOODING...
There is a high rip current risk along all ocean beaches through
this evening. A moderate rip current risk is expected on Sunday.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Heat Advisory from noon Sunday to 8 PM EDT Monday for
     NYZ072>075-176>179.
     High Risk for Rip Currents until 9 PM EDT this evening for NYZ075-
     080-081-178-179.
NJ...Heat Advisory from noon Sunday to 8 PM EDT Monday for NJZ004-
     006-103>108.
MARINE...Small Craft Advisory until 6 PM EDT this evening for ANZ350.

&&

$$

SYNOPSIS...JC/DS
NEAR TERM...JC/DS
SHORT TERM...JC
LONG TERM...JC/DS
AVIATION...JM
MARINE...JC/DS
HYDROLOGY...JC/DS
TIDES/COASTAL FLOODING...