146
FXUS61 KOKX 081127
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
727 AM EDT Mon Jul 8 2024
.SYNOPSIS...
A weak frontal boundary or surface trough will remain in close
proximity to the area through Wednesday. A low pressure system
approaches for Thursday with an associated cold front. This system
and its cold front are expected to slow down and weaken as they
continue to approach through Thursday night. The frontal boundary
becomes nearly stationary within or near the region going into
Saturday before dissipating Sunday.
&&
.NEAR TERM /THROUGH TONIGHT/...
High pressure nosing in from the NW across NY state and into
the forecast area this morning has allowed for a light northerly
flow. In return, the fog has not been as widespread across
eastern LI and coastal CT and has been varying quite a bit. Any
of this fog should quickly mix out after daybreak, with the
possible exception of locations along the immediate coast. Low
clouds/fog should generally park offshore during the daytime
hours before making a return visit later tonight. A weak frontal
boundary and/or surface trough that has pushed south of the
area this morning will return to the north or simply jump back
into the thermal trough that sets up. A weak onshore flow
develops by this afternoon. A few of the CAMs are hinting at a
pop shower and or thunderstorm today north and west of NYC.
Warming mid levels and still relatively dry air in the low
levels will keep the area generally capped.
More importantly though, it will remain very warm and humid
through the middle of the week. Upper air pattern reflects a
longwave trough centered over the midsection of the country and
a strengthening subtropical ridge over the western Atlantic.
Daytime highs will get into the lower 90s across portions of the
NYC/NJ metro and the interior, with the mid and upper 80s most
other locations. The immediate south shore of LI will be cooler.
This results in widespread 95 to 100 heat indices today across
much of the area except for coastal SE CT and eastern and
southern portions of LI. This will also continue into Tuesday
with values even a bit higher across NYC, NE NJ, and the Lower
Hudson Valley. Thus, a Heat Advisory remains in effect through
Tuesday.
Lows by daybreak Tuesday will be in the low to mid 70s with dew
points nearly the same.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
Continued very warm and humid Tuesday with heat indices of 95
to 100 and even a bit higher across portions of NE NJ and the
Lower Hudson Valley. In additions, there is a good chance that
head advisories will need to be extended into Wednesday for
portions of the area. However, convective debris and a
strengthening onshore flow presents some uncertainties at this
time.
Airmass gradually destabilizes during this time with deepening
low-level moisture. Warm heights still persist during this time
but chances of breaking the cap increase. Any convection
Tuesday afternoon/evening will be mainly north and west of NYC.
For Tuesday night, the coverage expands a bit with some warm
advection, but chances remain low. Any convection will be
capable of producing downpours with PWAT values increasing to
above 2 inches as we get into Wednesday. This combined with a
weak steering flow raises the potential for training of cells
from SW to NE. In addition, with a weak shear, moderate to high
CAPE environment north and west of NYC, pulse severe storms will
become possible. Once gain, most of the activity will be limited
to areas of the Lower Hudson Valley and interior NE NJ. However,
this is likely to expand east in the long term period.
Coastal low clouds and fog will also remain an issue,
especially across coastal SE CT and eastern LI with very high
dew point air traversing the cooler nearshore waters.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
-- Changed Discussion --
Wednesday night into Thursday we`ll be warm sectored as a warm front
passes to northward. The remnant low of Beryl will get absorbed into
a trough over the Great Lakes Thursday into Friday, and continue to
weaken into Saturday into Canada. The low will bring a cold front
towards us on Friday, then stall and linger before dissipating on
Sunday. However, a surface trough may remain into Monday.
As the remnant low of Beryl passes into the Great Lakes Thursday
into Friday, enhanced tropical moisture may be advected into
the area by a LLJ that develops as a result of the pressure
difference with the remnant low to our west and a strong
subtropical ridge to our east. This moisture will linger over
the area Thursday into Friday, before the cold front arrives
later on Friday lowering the PWATs to less anomalous values. A
vast majority of the 00Z GFS, ECMWF, and CMC ensembles agree on
very high maximum PWATs of 2.3-2.5" over the area on Thursday
and Friday. While too far out to pinpoint any flooding concerns
with much detail, since models still vary on timing and
coverage, it is possible we could see occasional downpours in
some showers and thunderstorms that come from this. However, the
brunt of the heavy rainfall looks like it may occur much
farther inland to our west and north. 00Z model sounds are
showing weak LCL-EL (Cloudy Layer) winds and tall, skinny CAPE
profiles with above average PWATS. They also show weak Corfidi
Upshear, indicating backbuilding/training of showers and storms,
despite strong Corfidi Downshear values, which indicates the
forward propagation of storms.
A 30-40 kt LLJ has been resolved by model 00Z global guidance over
our area Thursday into early Friday which, aside from helping advect
in more moisture, will also lead to breezy conditions. Currently
forecasting wind gusts 25-30 mph Thursday into early Friday.
Overall, its looking very muggy late this week into this weekend
thanks to warm temperatures and high dewpoints.
Aside from Thursday and Friday, rain chances will continue into
weekend thanks to a lingering frontal boundary on Saturday. While it
should dissipate on Sunday, a lingering surface trough could lead to
continue isolated chances of rain on Sunday, before a hint of a
drier pattern on Monday.-- End Changed Discussion --
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
A weak frontal boundary or surface trough will remain in close
proximity to the area today and tomorrow.
VFR for all terminals today. Possibly back to IFR/LIFR
conditions in the same areas that experienced issues early this
morning, Monday night/Tuesday morning.
Isolated showers/thunderstorms are possible N & W of NYC late
this afternoon/evening, but probability of occurrence is too
low to mention in TAFs.
A light NE flow will continue to develop this morning before
shifting to the S-SE 5-10 kt late morning into the afternoon
with a light sea breeze. Most go variable or settle with light S
winds Monday night/Tuesday morning.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of S-SE sea breeze winds Monday may be off by 1-2 hours.
Confidence is low on westward extent of IFR tonight/tomorrow
morning.
OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY...
Tuesday morning: VFR.
Tuesday afternoon through Friday: MVFR or IFR possible at times with
periods of showers/thunderstorms.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
A Dense Fog Advisory is in effect for the LI Sound east of the
CT River and for all ocean waters. The advisory expiration
varies from late morning to early afternoon and could very well
be extended for some portions. Episodes of fog and low clouds
will likely remain an issue through the week due to high dew
point air moving over the cooler waters.
With a relatively weak pressure gradient in place, conditions
on the waters are otherwise expected to be below small craft
advisory thresholds through Tuesday. A strengthening southerly
flow on Wednesday could bring marginal SCA conditions,
especially for the waters west of Fire Island Inlet.
For Thursday through Friday night, another low pressure system and
associated cold front approach but are expected to weaken. An
initial increase in the pressure gradient Thursday into early
Thursday night will weaken Friday through Friday night.
Possible SCA ocean seas Thursday with higher chances for SCA ocean
seas Thursday night through Friday night. Non-ocean waters stay
below SCA thresholds for seas and wave heights. For wind gusts,
possible SCA level wind gusts Thursday into Thursday night for ocean
waters and South Shore Bays.
So, SCA potential for ocean Thursday through Friday night. SCA
potential for South Shore Bays Thursday into Thursday night.
Otherwise, other waters are forecast to remain below SCA thresholds.
Below SCA waves and winds are expected this weekend.
&&
.HYDROLOGY...
There are no hydrologic concerns through Tuesday morning. Thereafter,
moisture increases along a stalled boundary and/or surface
trough nearby Tuesday afternoon, and even more so later in the
week with the approach of another frontal boundary. This will
bring a chance of minor/poor drainage flooding as well as
potential localized flash flooding Tuesday afternoon/evening to
the north and west of NYC.
Extended period with 2+ inch PWATS Wednesday night through Friday
and perhaps even through Friday night. Highest forecast PWATS
Thursday into Thursday night with potentially up to 2.5 inches. Any
thunderstorms Wednesday night through Friday will be capable of
producing heavy rain. There will be chances for minor flooding and
low probability, marginal risk, for localized flash flooding.
&&
.TIDES/COASTAL FLOODING...
There is a low rip current risk today with light winds and seas
2 to 3 ft. There is a moderate rip current risk on Tuesday as
southerly winds increase and seas may build a bit compared to
Monday.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory from noon today to 8 PM EDT Tuesday for
CTZ005>010.
NY...Heat Advisory from noon today to 8 PM EDT Tuesday for
NYZ067>075-078-176>178.
NJ...Heat Advisory from noon today to 8 PM EDT Tuesday for NJZ002-
004-006-103>108.
MARINE...Dense Fog Advisory until noon EDT today for ANZ332-350-353.
Dense Fog Advisory until 10 AM EDT this morning for ANZ355.
&&
$$
SYNOPSIS...BR/DW
NEAR TERM...DW
SHORT TERM...DW
LONG TERM...BR
AVIATION...BR
MARINE...BR/DW
HYDROLOGY...BR/DW
TIDES/COASTAL FLOODING...