859
FXUS61 KOKX 251820
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
220 PM EDT Sat May 25 2024
.SYNOPSIS...
High pressure today will give way to a weakening frontal system
this evening into early Sunday. A surface trough lingers nearby
on Sunday. A stronger frontal system will impact the area
Monday into Monday night with a series of fronts following it
Tuesday into Wednesday. An upper level disturbance may impact
the area towards the end of next week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
-- Changed Discussion --
Weak high pressure over the area will continue to shift farther
offshore this afternoon. An upper ridge axis will also slide
across New England. A flat middle level shortwave quickly
follows this evening into tonight, which will bring a weakening
frontal system into the area.
It will remain dry through early this evening as subsidence
lingers due to the aforementioned ridging. There will be
increasing middle and high level clouds with the approaching
shortwave, especially in the afternoon and evening.
Highs will be above normal, ranging from the mid to upper 70s
near the coast to the lower and middle 80s in the NYC metro and
areas to the NW. Hybrid seabreeze/SE synoptic flow will push
well inland today, likely capping temp rise in the early to mid
afternoon for much of the coastal plain. Immediate south coastal
locations will likely hold temps in the upper 60s to lower 70s
with onshore flow already developing.
A broken line of showers should be approaching from the NW
this evening in association with the shortwave and weakening
front. CAMs all show this line weakening as it enters the NW
interior sometime between 7pm-10pm. There is only a marginal
amount of CAPE aloft and the latest forecast soundings indicate
a lingering middle level cap. For these reasons, have left
mention of thunder of the forecast. Otherwise, a low chance PoP
exists initially this evening over western Orange County with a
slight chance slowly making its way east through the night.
Surface convergence along the front may be able to generate a
few showers overnight as the boundary washes out or stalls over
the region. This is due to the shortwave flattening and heights
beginning to rise towards early Sunday morning. Lows will be in
the upper 50s and lower 60s.-- End Changed Discussion --
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
The lingering boundary becomes difficult to discern Sunday
morning and the latest guidance is indicating that it should
largely become a surface trough by afternoon. A lingering
isolated shower is possible in the morning. The trough likely
retrogrades inland in the afternoon with the development of sea
breezes. Ridging builds aloft, so there is not any significant
forcing for organized convection. The convergence along the
surface trough may be enough to trigger a shower or thunderstorm
in the afternoon and early evening well north and west of the
NYC metro. Forecast soundings show more instability, but there
will likely be a cap around 5 kft, limiting organization. Sunday
may be a bit more humid compared to Saturday with similar
temperatures.
Any early evening convection dissipates with loss of heating.
Attention will then quickly turn to the next shortwave and
associated low pressure over the midwest. This system will
send a warm front north of the area late Sunday night into
Monday morning aiding in increasing chances for showers and
possibly a thunderstorm. The system will draw in a stronger
onshore flow component, which will limit surface instability
with the warm front. The low pressure will continue deepening as
it moves through the Great Lakes on Monday and then into
southeast Canada Monday night. The low will bring a deeper
moisture feed with PWATs reaching 1.50- 1.75 inches Monday
afternoon into Monday night. The associated cold front should
begin entering the area from the west late in the day and then
move across the rest of the region Monday night. There is
potential for multiple rounds of showers and embedded
thunderstorms along and ahead of the front. The overall system
should remain progressive, which will limit the flooding
potential.
WPC has continued to highlight portions of NE NJ and the
Lower Hudson Valley in a slight risk for excessive rainfall.
This area has a bit higher chance at seeing heavier rainfall
which could lead to flash flooding. Elsewhere, the risk is
marginal with an isolated flash flood risk. The modest onshore
flow and abundant cloud cover will limit instability and any
severe thunderstorm risk. Average rainfall amounts range from
around a half to three quarters of an inch east of the Hudson
River and NYC metro to around one inch west of NYC. Locally
higher amounts are possible.
Showers and embedded thunderstorms will continue pushing
offshore late Monday night into early Tuesday morning. The
cold front may linger over eastern Long Island and southeast
Connecticut as the upper trough remains well to the west.
However, the deep moisture feed will likely be located offshore.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Not much change in the long term and stuck fairly close to
the previous forecast/NBM.
A cold front exits the area Tuesday morning with what should
be mainly a dry day. Another shortwave/cold front is expected
to move across the area on Wednesday. There are some timing
issues with this second cold front, which could become
significant in how quickly the airmass can destabilize ahead of
an approaching cold front on Wednesday. For now, will cap POPs
at chance and will mention scattered convection.
For the end of the week, high pressure builds in on Thursday,
but this will depend on how quickly the energy exits to the east
and there are differences. The 00Z ECMWF continues to cut off
an upper low across the area by Friday. This could result in
clouds and showers each afternoon.
Temperatures do cool down a bit at the end of the week, closer
to normal, but with an amplifying upper trough an/or closed low,
this may start trending down. The warmest day of the week will
be Tuesday, with highs in the upper 70s and lower 80s for much
of the area. lower to middle 70s can be expected closer to the
coast.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
-- Changed Discussion --
High pressure remains in control today. A weakening cold front
approaches late tonight and stalls nearby on Sunday.
VFR through at least early evening. LIFR stratus anticipated at
KJFK/KISP/KBDR/KGON overnight before dissipating by mid-Sunday
morning. Slight chance of showers after midnight for the city
and terminals and KSWF/KHPN.
SE-S winds around 10 kt. Winds veering slightly this evening
while diminishing, eventually bcmg more S-SW or light and
variable by the end of the night.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Chance that low cigs and vsbys do not occur tonight at KJFK. A
low chance that low cigs and vsbys spread to KLGA after
midnight.
OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY...
Sunday PM: VFR. Chc TSTM for KSWF/KHPN.
Monday: IFR. Chc morning showers, then PM showers likely and chc
of TSTM. SE gusts 20-25kt possible for coastal terminals.
Tuesday: IFR/MVFR early, improving to VFR by noon.
Wednesday: Chance of aftn TSTM and MVFR.
Thursday: Mainly VFR. Slight chc shra/TSTM.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
A weak pressure gradient and lack of significant swell will lead
to conditions below SCA levels through Sunday night. A strengthening
S-SE flow on Monday could into result in marginal SCA
conditions on the ocean waters, mainly late in the day into the
first half of the night.
Winds and seas will generally remain below SCA criteria for the
middle and end of the week, however with thunderstorms possible over
portions of the waters especially Tuesday and Wednesday, there will
be a chance of brief SCA conditions in the storms.
&&
.HYDROLOGY...
A frontal system Monday into Monday night may bring several
rounds of moderate to heavy rainfall. There remains uncertainty
with the axis of heavy rainfall, but chances remain highest for
heavier rainfall across NE NJ and the Lower Hudson Valley. This
is where WPC continues to highlight a slight risk for excessive
rainfall and a bit better chance for scattered flash flooding.
The risk is marginal elsewhere with just isolated flash flood
potential.
&&
.TIDES/COASTAL FLOODING...
A southerly flow at 5-10 kt and a southerly swell of 1 ft 8-9s
should keep the rip current risk low through Sunday. This
continues to be supported by latest RCMOS at area beaches.
The rip current/longshore current risk will likely increase to
moderate through the afternoon Monday as E/SE winds strengthen
and SE wind waves build to 3 to 4 ft.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...BC/DS
NEAR TERM...DS/NV
SHORT TERM...DS
LONG TERM...BC
AVIATION...JC
MARINE...BC/DS
HYDROLOGY...BC/DS
TIDES/COASTAL FLOODING...