119
FXUS61 KOKX 151141
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
741 AM EDT Thu Aug 15 2024

.SYNOPSIS...
A weak disturbance moves through today with high pressure
otherwise in place through Friday night. A warm front then
approaches from the west Saturday into Saturday night. The
associated frontal system continues to approach Sunday, with an
attendant cold front moving through late Monday or early Tuesday.
High pressure then returns into mid next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
The forecast is mainly on track. Only hourly temperatures and
dewpoints for the next few hours were adjusted with this update
to better fit the latest trends.

500mb low remains spinning over the Canadian Maritimes today. This
will promote a cyclonic flow aloft over the forecast area and help
steepen mid-level lapse rates. Shortwave lift pivots through the
region as well - stronger over the eastern zones. Expecting
scattered showers and thunderstorm with this setup. Similar to
yesterday, additional convection could spring up along outflow
boundaries, and strong gusts may occur with a dry sub-cloud layer.
Csn`t even rule out at least small hail over the CT zones given
stronger shear plus the amount of CAPE in the hail growth zone with
favorable wet-bulb zero heights. The day otherwise starts with
sunshine filtered through some cirrus clouds before cumulus/convective
debris increase during the afternoon. Highs in the middle and
upper 80s for most spots.

Any lingering convection diminishes this evening with the loss of
daytime heating, followed by dry conditions overnight. NBM looked
good for low temperatures.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Upper low over the Canadian Maritimes drifts east, allowing for deep-
layered ridging over us and dry weather. Highs generally 85-90, and
getting a little more muggy. A warm front associated with low
pressure moving through the Great Lakes then slowly approaches
Friday night through Saturday night. Overrunning moisture ahead
of the front brings us a chance of showers starting on Saturday.
Showers then become more likely Saturday night as the front nears.
Western zones will have higher chances being closer to the lift
associated with the warm front. Higher elevated instability will
reside there too, so kept in a slight chance of thunderstorms as
well. NBM was used for temperatures.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
An upper trough sits over the Eastern US to start the period, with a
frontal system attempting to work through the region. Meanwhile,
Hurricane Ernesto will be making it`s closest approach to the region
on Sunday, though still passing hundreds of miles offshore as it
treks into the North Atlantic. Local impacts will be limited to
elevated surf and dangerous rip currents along area beaches early
next week, and additional information on this threat can be found in
the tides and coastal flooding section farther down. Please refer to
the NHC for official forecast information on Ernesto.

A couple rounds of shower and thunderstorm activity moves through
with the frontal system, the first late Sunday into Sunday evening,
and another ahead of a trailing cold front late Monday into early
Tuesday. Parameters don`t appear too threatening in terms of
widespread severe weather, relatively low instability and shear,
though locally heavy downpours are possible and could lead to
nuisance flooding.

The system looks to finally exit offshore Tuesday, and drier
conditions advect down into mid next week as heights rise and weak
surface high pressure builds in from the Midwest. Capped PoPs at 60%
with the frontal system, but largely followed the national blend for
this update.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
Weak high pressure generally remains in control through the TAF
period. VFR forecast.

Mainly a light N/NW flow this morning, and a similar flow
persists today, though sea breezes turn coastal terminals southerly
or southwesterly by late afternoon, before becoming light and
vrb tonight with high pressure settling overhead. Flow becomes
southerly Friday afternoon as the high shifts offshore. Speeds
remain at or under 10 kt.

A few scattered showers or thunderstorms are possible this afternoon
and early evening, generally between 18Z and 00Z, with the best
chance of seeing this at inland and CT terminals, KSWF, KHPN,
KBDR, and KGON. Brief category declines possible with any
heavier shower or a thunderstorm. Though this is also possible
at NYC and LI terminals, coverage is expected to be more isolated
closer to the coast and have left out of TAF at this time. Any
activity dissipates in the early evening, and skies clear
overnight into Friday morning.

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

AMD possible late this morning and afternoon for timing of sea
breeze.

Low potential for showers and thunderstorms this afternoon.

OUTLOOK FOR 12Z Friday THROUGH MONDAY...

Friday: VFR.

Saturday and Sunday: Showers likely with chance of tstms, especially
in the afternoon/early evening, and especially from the NYC metros
north and west. MVFR or lower conditions possible.

Monday: Mainly VFR. MVFR or lower possible in any SHRA/TSRA in the
afternoon.

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

&&

.MARINE...
High pressure provides a weak pressure gradient and a light wind
regime overall through Friday with sub-SCA levels. However, the
combination of southerly winds with an approaching frontal system
and increasing long period S to SE swells from Hurricane Ernesto
during Friday night into Saturday will build ocean seas to 5 to 6
feet Saturday, and 6 to 7 feet Sunday. Seas peak Sunday and
subside Monday into Monday night.

A small craft advisory will likely be needed on the ocean
waters for Friday night through Monday night. Please refer to
the NHC for official forecasts of Hurricane Ernesto.

&&

.HYDROLOGY...
No impacts expected with today`s isolated to scattered
shower/thunderstorm activity. The next chance of rain will then be
on Saturday, with better chances Saturday night. Anticipated
rainfall during this period is only up to around a quarter inch,
thus no impacts are expected for now, but there`s still a chance for
models to trend with higher rain amounts and introduce the
possibility of minor nuisance/poor drainage flooding.

Showers and thunderstorms Sunday and Monday could produce locally
heavy downpours that lead to nuisance flooding of urban and poor
drainage areas. At this time, the risk for flash flooding is
low.

&&

.TIDES/COASTAL FLOODING...
The rip current risk starts out as low this morning, but will be
increasing to moderate this afternoon, then continue to increase
into Friday, reaching a high risk Friday afternoon and likely
remaining that way through the upcoming weekend. The increasing rip
current risk is due to increasing incoming SE to S long period
swells from Hurricane Ernesto. Please refer to NHC for official
forecasts regarding Hurricane Ernesto.

Minor coastal flooding may be possible early next week during high
tide cycles Sunday through Tuesday as swells build and astronomical
tides increase due to the full moon on Monday.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.

&&

$$

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