208
FXUS61 KOKX 141731
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
131 PM EDT Mon Jul 14 2025

.SYNOPSIS...
A weak cold front approaching from the west today will move
through tonight, and pass to the south Tuesday morning. The
front should dissipate during mid week, allowing the Bermuda
high to exert more influence for mid to late week. A cold front
will likely move through this weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Points:

* Flood Watch remains in effect from 2 PM to midnight for NE NJ,
  the lower Hudson Valley, NYC, and SW CT.

* Scattered instances of flash flooding are possible from NE NJ
  into the lower Hudson Valley.

* More isolated instances of flash flooding are possible east of
  there into NYC and SW CT.

A shortwave trough axis over the eastern Great Lakes/Ohio
Valley, and accompanying sfc trough over central NY/PA, will
both slide east toward the region today, and move across
tonight into early Tue morning.

With a moist and marginally unstable air mass (PW 1.86" and
moist adiabatic lapse rates through the column on KOKX 12Z
sounding) there is potential for isolated downpours with any
morning showers that develop. Otherwise, morning low clouds
should should give way to breaks of sun this afternoon,
particularly away from the immediate south coasts.

Daytime heating will lead to marginal to locally moderate
instability (MLCAPE 500-1500 J/kg). In a tropical environment
with approaching shortwave, this will be supportive of
scattered tstm development along outflow from decaying AM
convection moving from the Poconos and Sullivan County toward
the Lower Hudson Valley and northern NJ, and also along sea
breeze boundaries across Long Island/NYC metro/S CT this
afternoon, then scattered to numerous tstm development
along/ahead of the approaching pre-frontal trough late this
afternoon into this evening.

Threat will be for torrential downpours from tstm activity with
2+"/hr rainfall rates likely in a tall and narrow CAPE profile
environment, PW increasing to near 2.25" (+2 standard deviations
from the mean), deep warm cloud layer up to 15 kft, and weak SW
steering flow (15kt) aligned with trough/seabreeze/outflow
boundary.

Highest coverage/confidence in this activity is across
NE NJ and LoHud in vicinity of sea-breeze/outflow convergence
boundary and then followed by approaching trough, with scattered
instances of flash flooding possible (25-35% probability
within 25 miles of a point).

Farther east across NYC and SW CT, confidence in coverage of
convection is slightly lower (10-20% flash flood probability
within 25 miles of a point prob) as sea breeze/outflow activity
likely end up to the north/west, with more organized trough
activity late in the day potentially weakening in intensity with
waning instability, although this could be counteracted by
potential increase in LLJ and shear/helicity with hints of weak
surface wave development. In any case, a lower confidence on
flash flood threat exists for this area.

Weak low level shear/helicity profiles and weak LLJ also appear
to be a limitation for sustained updraft and backbuilding storms
and a moderate flash flood threat for NE NJ/LoHud, with later
trough approach and waning instability this evening a possible
limiting factor for NYC and SW CT.

After collab with WPC and surrounding offices issued Flood
Watch from 2 PM to midnight for NE NJ, LoHud, NYC and interior
SW CT, for widespread 1-3 inches of rainfall likely, and locally
as high as 5 inches, for NE NJ and LoHud where most
persistent/widespread convection is likely based on predicted
synoptic/mesoscale environment and CAM output. HREF shows up to
50% probability of 3 inches in 3 hours across NE NJ, which is a
rare signal. Meanwhile, a widespread 1/2 to 1 1/2 inches
rainfall is likely with localized rainfall totals of up to 3
inches possible for NYC and SW CT. Most of this could fall in
as little as a 3-hr period.

Isolated strong to severe wet downbursts are possible, mainly
NW of NYC.

Shortwave trough axis slowly slides east tonight into early
Tuesday morning, with weak surface trough axis sliding
southeastward through Long Island/CT. Convective coverage and
intensity will wane overnight, but potential for locally heavy
downpours and embedded tstm activity may continue invof the
trough and possible weak wave development.

Seasonably warm and very muggy conditions will prevail through
tonight.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Key Points:

* Moderate potential for heat indices of 95-100F on Wednesday.

Shortwave trough axis slowly slides east Tuesday morning, with weak
trough axis likely dropping south. Potential for locally heavy
downpours and embedded tstm activity in vicinity of the trough
across LI/SE CT Tue AM, then gradual mid-level drying
conditions expected Tue afternoon in wake. Low chance of
afternoon shra/tsra activity for NYC and pts N&W Tue aft during
peak heating.

Seasonable temps and very humid conditions continue Tue into
Tue Night. Patchy stratus/fog development possible Tue Night/Wed
Am in the moist and weak flow environment, particularly along
the coast.

Shortwave ridging surface/aloft should allow for more in the way
of sunshine on Wednesday, with warm advective SW flow
establishing around Bermuda high. Potential for start of a mid
to late week heat wave, with widespread daytime temps in the
upper 80s to lower 90s, and Tds in the lower to mid 70s.
Widespread heat indices of 95-100F possible. Late day/evening
convection possible with approach of southern shortwave/pre-
frontal trough.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Key Points:

* While still some uncertainty, there is the potential for a
  heat wave to continue Thursday and Friday for many areas with
  max heat index values between 95 and 105.

* Relatively active pattern with chances for several days of afternoon
  showers and thunderstorms.

A frontal boundary will likely stall just offshore and linger,
possibly lifting north of the area Thursday. A frontal system may
then impact the area later in the week. Aloft, the pattern stays the
same through the period. Although we are under some high heights, we
are somewhat on the eastern end of a broad upper level trough
centered over central Canada and few shortwaves likely pass through.

With strong Bermuda high in place, a S/SW flow will allow plenty of
moisture to be sent our way. This combined with above normal high
temperatures brings some potential for a heat wave, with heat index
of 95-105 Thursday and Friday. However, there still is uncertainty
especially given the potential for convection and slight
inconsistencies in a late week frontal system among the guidance.

Too early to talk specifics when it comes to severe or flooding
concerns with the aforementioned convection. These details will be
ironed over the next few days. There is plenty of moisture around
with pwats 1.75-2.00+ for Thursday and Friday so any convection that
does develop will likely be able to produce heavy downpours. As for
severe, while we are pretty unstable, shear looks weak through much
of the period.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
A weak cold front settles over the terminals this afternoon and
evening, gradually sinking to the south tonight.

Mainly VFR this afternoon with MVFR ceilings possible across
eastern Long Island and southeast Connecticut. Showers and
thunderstorms will continue expanding in coverage this
afternoon, especially from NYC terminals on north and west.
Showers/thunderstorms this evening slowly push east and weaken,
with a few showers lingering overnight. Torrential downpours with
MVFR/IFR conditions possible in any shower/thunderstorm.

Low confidence flight category forecast tonight into early
Tuesday, but MVFR conditions possible at all terminals. IFR
also possible, especially across eastern Long Island and
southeast Connecticut. Conditions should become VFR Tuesday
morning.

S-SE winds around 10 kt this afternoon. Winds will diminish
tonight then become SW-S under 10 kt Tuesday morning.

 ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments for timing of showers and thunderstorms possible.

Low confidence flight category forecast tonight/early Tuesday
morning.

.OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY...

Tuesday Afternoon-Night: VFR during the afternoon/evening with a
chance of a shower/thunderstorms. MVFR or lower possible,
especially east of NYC metro at night.

Wednesday-Friday: MVFR or lower in any afternoon/evening
showers/thunderstorms.

Saturday: Mainly VFR.

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

&&

.MARINE...
With a weak pressure gradient, winds and seas likely remain
below SCA criteria through the weekend. However, afternoon
showers/tstms through the period could produce locally higher
winds/seas at times.

&&

.HYDROLOGY...
Flood Watch remains in effect from 2 PM to midnight for NE NJ,
the lower Hudson Valley, NYC, and SW CT.

A widespread 1-3 inches of rainfall is likely, and locally as
high as 5 inches across NE NJ and LoHud where most
persistent/widespread convection is likely based on predicted
synoptic/mesoscale environment and CAM output.

A widespread 1/2 to 1 1/2 inches of rainfall is likely with
localized rainfall totals of up to 3 inches possible for NYC and
SW CT.

Most of the above could fall in as little as a 3-hr period.

Highest coverage/confidence in this activity across NE NJ and
LoHud in vicinity of sea-breeze/outflow convergence boundary
followed by approaching trough with scattered to numerous
instances of flash flooding possible (15-25% probability within
25 miles of a point).

Rainfall rates of 2+"/hr possible with stronger and/or
repetitive convection, which would cause localized instances
of severe flooding.

&&

.TIDES/COASTAL FLOODING...
The rip current risk is low through Tuesday, with a 10 kt or
less onshore flow and weakening S-SE swell.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Flood Watch until midnight EDT tonight for CTZ005-006-009.
NY...Flood Watch until midnight EDT tonight for NYZ067>075-176-178.
NJ...Flood Watch until midnight EDT tonight for NJZ002-004-006-
     103>108.
MARINE...None.

&&

$$

SYNOPSIS...BG/JP/NV
NEAR TERM...BG/NV
SHORT TERM...NV
LONG TERM...JP
AVIATION...DS
MARINE...JP/NV
HYDROLOGY...BG/JP/NV
TIDES/COASTAL FLOODING...