okx-afd on 2024-07-10

900
FXUS61 KOKX 110023
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
823 PM EDT Wed Jul 10 2024

.SYNOPSIS...
A cold front approaches from the west tonight and stalls over the
area on Thursday. The frontal boundary remains within the vicinity
of the local area into next week.

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
-- Changed Discussion --The forecast remains on track. Convection ahead of the cold
front is pushing east through southcentral NY and into eastern
PA at this time. Mesoanalysis and recent WoFS runs show
increasing stability/MLCIN over the next few hours as the
storms push east in a more unfavorable environment. This should
aid in some weakening as the complexes head east arriving near
the CWA around 03Z. Previous discussion follows.

A cold front approaches from the west tonight,
bringing a weakening area of showers with embedded thunderstorms
as CAPE diminishes. Best chances of showers will be after
midnight. Some MUCAPE will still be present when the front and
shortwave lift move through so can`t rule out an isolated
thunderstorm. Additional lift over the eastern zones will be
provided by a strengthening low level jet ahead of the of the
cold front. While mid level shear will be modest, instability
will be lacking, so severe thunderstorms are not anticipated. A
strong gust or two may still occur nevertheless. PWATs around
2.25 inches will however promote a low risk of flash flooding in
any thunderstorms, but the more likely scenario will be
minor/poor drainage flooding should a thunderstorm occur. Muggy
conditions through the night with lows in the 70s.-- End Changed Discussion --

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
The front stalls over the area on Thursday with the moisture axis to
its east. The frontal boundary and moisture axis are then progged to
shift back west/east over us through the short term period as weak
ridging arrives from the east through Friday and then a wave of low
pressure forms along the frontal boundary to our south Friday night.
Additional steering influence will come from a shortwave heading
into the Saint Lawrence River Valley. Models still disagree as to
where the axis of deepest moisture (with PWATs around 2.25 inches)
drifts through Friday night, which presents challenges in
forecasting where the greatest flooding potential will exist.
There`s at least general agreement that the better chance of
flooding would occur Friday afternoon and night with the approach of
lift from the south associated with low pressure wave. So after
chance/slight chances of showers and thunderstorms Thursday and
Thursday night, rain with embedded thunderstorms becomes likely for
Friday and Friday night. See the hydrology section below for more
details.

Muggy conditions continue through the short term period, but at
least heat indices should remain below advisory thresholds both
days.

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

* Warm and humid conditions will be on the increase once again, with
excessive heat and humidity possible again Sunday through the
middle of next week.

* A unsettled pattern also continues into next week. While not a
washout by any means, precipitation chances remain in the
forecast, especially Monday and Tuesday of next week.

Subtropical ridge that has influenced our weather as of late will
begin to shift southeast on Saturday as an upper trough passes well
to the north. This will result in mainly zonal flow aloft through
the weekend. Weak ridging begins to build in aloft, thereafter.

At the surface, a weak boundary remains stalled near or just south
of the area over the weekend. This boundary slowly slides south and
dissipates by early next week. Thus, have kept precipitation
chances, slight to chance, in the forecast each day. Any remnant
precipitation should shift offshore by Saturday afternoon.
Mainly dry conditions are expected thereafter into Sunday. By
Sunday night into Monday, a weak shortwave aloft may instigate
some afternoon showers/thunderstorms.

By Sunday, 850 temps begin to warm, and continue to do so through
early next week, peaking at 19-23C. With southwesterly sfc flow
ramping up Sunday into Monday, expecting dewpoints in the low 70s by
early next week and temperatures in the upper 80s and lower 90s.
This will put heat indices Sunday in the mid 90s for NE NJ, NYC and
parts of the Lower Hudson Valley/SW CT. This looks to continue into
Monday and Tuesday, and would require heat headlines should
confidence increase.

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
A cold front approaching from the west moves into the western
terminals this evening, then becomes nearly stationary late
tonight. The front remains over or near the area through the TAF
period.

MVFR to IFR cigs for a period tonight. Improvement starts late
tonight/early Thursday morning behind cold frontal passage. Low
cigs may hang around KISP and KGON through late morning/early
afternoon.

Ahead of the cold front, a broken line of showers/thunderstorms
is expected for western terminals between 02z and 07z. This
activity is expected dissipate/weaken before reaching KBDR, KISP
and KGON.

Winds remain southerly with gusts 20-30kt, highest and most frequent
along the coast. Winds gradually shift to the SW early tonight,
especially in the NYC metro area, and winds shift more westerly
at KSWF late tonight with the cold front moving into the
region. Gusty southwest winds expected again on Thursday around
20 to 25 kt.

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

Showers/thunderstorms possible sometime between 03z and 07z.
Confidence in thunder higher at KEWR and KTEB.

Higher confidence in MVFR cigs at KJFK and KLGA.

OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...

Thursday night through Saturday: MVFR or lower possible at times
with periods of showers/thunderstorms. Otherwise VFR.

Sunday: VFR.

Monday: VFR. A chance of afternoon 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...
SCA has been extended to include all of Thursday night on the ocean
as seas will remain elevated. The threat of gusts of up to 25kt
however ends Thursday evening. The advisory will likely need to be
extended into Friday as seas remain elevated with some swell.

Winds and waves look to remain below SCA thresholds on all
waters Saturday through Sunday evening with a weak pressure
gradient in place.

.HYDROLOGY...
Heavy rain remains a possibility with any showers/thunderstorms that
develop early next week with an increasingly warm and humid airmass
in place. It is too early to ascertain any specific rainfall
amounts, but localized heavier rainfall can be expected with any
convection.

.TIDES/COASTAL FLOODING...
There is a high risk of rip current development along all ocean
beaches today through Thursday. Onshore flow becomes more gusty
with building ocean seas.

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --CT...None.
NY...High Risk for Rip Currents through Thursday evening for NYZ075-080-
081-178-179.
NJ...None.
MARINE...Small Craft Advisory until 6 AM EDT Friday for ANZ350-353-355.-- End Changed Discussion --

SYNOPSIS...JC/DBR
NEAR TERM...JC/DBR
SHORT TERM...JC
LONG TERM...DBR
AVIATION...JT
MARINE...JC/DBR
HYDROLOGY...JC/DBR
TIDES/COASTAL FLOODING...