692
FXUS61 KOKX 161432
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1032 AM EDT Tue Jul 16 2024

.SYNOPSIS...
A surface trough remains in place today. A cold front approaches
from the west Wednesday, moving through late Wednesday night into
Thursday morning. High pressure then follows for late week, and
should remain nearby into the upcoming weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Warm and muggy to start, with another hot and humid day ahead.
Spotty patchy fog and mist early this morning along some of the
coast dissipates by mid morning.

Guidance consensus progs H85 temps 21 or 22C today, yielding
surface temperatures into the 90s once again for most areas with
sufficient mixing of the BL. Some of the warmest locales in
urban NE NJ may touch triple digits. Increasing SW flow should
allow dew pts to fall from the low to mid 70s this morning back
into the upper 60s this afternoon. With these values, heat indices
approach or exceed 100F across much of the region once again
this afternoon. Heat Advisory remains in place today for all but
SE Suffolk and coastal New London.

Then into this afternoon, yet another mid level shortwave in the
flow approaches, and CAMs depict clusters of convection developing
along with it into the evening given a modestly unstable air mass.
Forecast soundings peg DCAPE values near 1000 J/kg over the
LoHud Valley, and with effective shear toward 30 kt, should be
sufficient to support organized cells and line segment development
capable of producing strong wind gusts. Any potential convective
debris clouds would probably occur late enough in the day to
limit the impact on potential high temperatures or heat indices.
Timing looks late afternoon for far western parts of the region,
working into NYC and metro by early evening, and points east
into the evening as activity likely weakens with loss of heating.
SPC has expanded their slight risk to include much of the region,
with the exception of eastern Long Island and SE CT, where a
marginal is in place. And with a moist environment to work with,
torrential downpours are possible with any thunderstorm and
lead to flooding, primarily of urban and poor drainage areas.

Conditions dry tonight and another very warm and humid night
expected, with lows again near 80 in NYC and in the mid/upper
70s most elsewhere.

&&

.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
One more afternoon of dangerous heat and humidity across much
of the region Wednesday before a respite. Digging trough will
push a cold front toward the region, instigating convection once
again in the afternoon and evening. Ahead of it, temperatures
climb into the upper 80s to mid 90s, and heat indices likely top
out between 95 and 100. Extended the Heat Advisory thru
Wednesday for all areas but SE Suffolk and coastal New London
with increased confidence in coverage of these values.

Showers and thunderstorms become likely by late afternoon for
western areas, spreading east and persisting thru the evening,
before the fropa is expected to move through overnight into early
Thursday morning. SPC has outlined a slight risk for the LoHud
Valley, NE NJ, NYC, and western LI, with a marginal farther
east. Damaging winds will be the primary hazard, though torrential
downpours with this activity could lead to flooding. The 00Z HREF
highlighted a low (10%), but non zero, chance of some areas
recording 3 inches in 3 hr, which can be a good signal for a
heavy rainfall potential. More likely though, is a lower end
nuisance type flooding. The showers and storms likely linger
overnight, gradually ending from west to east working into
Thursday.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
The main story for the long term will be relief from the high
heat and humidity that currently persists over the region.

Key Points:

* A cold front will continue working offshore on Thursday. A few
  showers, possibly a thunderstorm may linger nearby in the
  morning with dry conditions becoming likely in the afternoon
  and evening.

* Daytime temperatures will return to near seasonable levels
  Thursday and Friday with dew points falling into the lower and
  middle 60s, potentially upper 50s in spots.

* A slight moderating temperature trend is possible for the
  upcoming weekend, but highs will still be in the middle to
  upper 80s with dew points in the 60s.

* Mainly dry conditions should persist into the upcoming
  weekend.

Upper level trough will continue over the region on Thursday
with the cold front pushing offshore. The deep moisture axis
and main area of forcing follows, but there could be some
lingering showers in the morning, especially closer to the
coast. A thunderstorm is possible, but instability will be
diminishing as the front pushes further offshore. Model trends
continue supporting the end of any showers Thursday afternoon
and have trended PoPs lower than the latest deterministic NBM.

The upper trough axis will likely swing across the area Thursday
night into Friday morning. Broad troughing will then persist
aloft into the start of the weekend, with a more amplified
trough passage late in the weekend. The main uncertainty will be
how much moisture will be able to return to the region. Forcing
continues to look weak, but there is a signal for a weak
surface trough or front nearby which could be a mechanism for
convection. The deepest moisture and more organized forcing
stays largely north. Will continue to keep the forecast dry
through the weekend/next Monday, which is in line with the
latest model consensus.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
A surface trough will remain nearby into tonight.

VFR through at least early afternoon with SW winds 5-10kt
backing more southerly for the afternoon and increasing 10 to
around 15kt with gusts 20-25kt. Winds and gusts, especially
along the coast will be a few knots higher during the afternoon.
Changed the PROB30s to TEMPOs for TSRA, and adjusted the timing
an hour later. There is a chance that any late afternoon storms
will have stronger westerly gusts, and added to the inland
terminals.


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

Timing of convection may be off by a couple of hours. Iso
shra/tstm possible for an hour or two on either side of TEMPO
timing.

Chance that winds back about 20 degrees more than currently
forecast this afternoon ahead of the potential convection.


OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...

Wednesday: VFR to start. MVFR or lower in showers and
thunderstorms afternoon into the evening, with a chance of
showers and thunderstorms late at night.

Thursday: Mainly VFR. Chance of showers and thunderstorms mainly
in the morning.

Friday and Saturday: VFR.

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

&&

.MARINE...
A period of marginal SCA conditions is possible on local ocean
waters late this afternoon with occasional 25 kt gusts from the
south and seas building to 4 or 5 ft.

Advisory conditions become more likely on the ocean waters late
Wednesday afternoon as seas build to between 5 and 7 ft ahead
of an approaching cold front. These elevated seas may linger
into Thursday afternoon before subsiding.

Thereafter, sub SCA conditions expected on all waters through
the weekend.

&&

.HYDROLOGY...
With a humid air mass in place, any thunderstorms that develop
through Wed night will have the potential to produce downpours
capable of causing at least minor urban and poor drainage flooding.

No hydrologic impacts are anticipated Thursday through the upcoming
weekend.

&&

.TIDES/COASTAL FLOODING...
There is a moderate rip current risk on the ocean beaches into this
evening due to 3-4 ft S swell of 6-8s and S winds 10-15 kt. Seas
increase on Wednesday to near 5 ft, and with a 15 kt flow, supports
a high rip current risk along local Atlantic beaches.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory until 9 PM EDT Wednesday for CTZ005>011.
     Air Quality Alert until 11 PM EDT this evening for CTZ005>007-
     009>011.
NY...Heat Advisory until 9 PM EDT Wednesday for NYZ067>075-078>080-
     176>179.
     Air Quality Alert until 11 PM EDT this evening for NYZ067>075-
     176-178.
NJ...Heat Advisory until 9 PM EDT Wednesday for NJZ002.
     Air Quality Alert until 11 PM EDT this evening for NJZ002-004-
     006-103>108.
     Heat Advisory until 10 PM EDT Wednesday for NJZ004-006-103>108.
MARINE...None.

&&

$$

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