778
FXUS61 KOKX 141017
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
617 AM EDT Sun Jul 14 2024

.SYNOPSIS...
High pressure will be in control today with a thermal trough setting
up over the region Monday and Tuesday. A cold front approaches from
the west on Wednesday, moving through Wednesday night into Thursday.
High pressure then builds in for the end of the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
A special weather statement has been issued for SE Suffolk
County and Southern New London County for locally dense fog. Fog
should burn off 8 or 9 am. Rest of the forecast is on track.

A stationary front remains over the region today, but without much
of consequence as high pressure will be the main feature today. It
should be a dry day for most, if not all of the forecast area. The
only exception would be a low chance of a shower or thunderstorm
this afternoon west of the Hudson River as MLCAPE increases to 500-
1000 J/kg and a weak shortwave approaches from the west, perhaps
providing just enough lift and instability to overcome a mid-level
cap. CAPE and CIN will be more favorable just off to our west, so
anything that develops there could drift into the forecast area.

No changes with the heat advisory today. Models continue to show 850
mb temps mostly 17-19C during the afternoon, highest west of the NYC
metro. Afternoon sea breezes are likely to develop, so dew points
near coastal locations may not be able to have dew points mix out a
bit. There is a good consensus among the guidance for highs to reach
the upper 80s and lower 90s, warmest across NE NJ, NYC, and interior
Lower Hudson Valley and interior southwest CT. Heat indices will
peak at or just above 95 over the urban corridor in NE NJ, NYC
metro, and Nassau. It is possible that some locations near the south
coast fall just short of a 95 heat index. Elsewhere, max heat
indices should reach the upper 80s and low 90s. No changes with the
Heat Advisory for today.

Warm and muggy conditions for tonight. Will leave fog and stratus
out of the forecast as winds just above the boundary layer look too
strong for the most part. Should any occur, it would more likely be
over eastern LI and SE CT.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
Similar setup both days with a thermal trough over the area, and
shortwaves bringing shower/thunderstorm potential in the afternoon
and evening hours. Somewhat better chances of thunderstorms on
Monday versus Tuesday with the main threat being strong gusts both
days.

Based on an average of deterministic and ensemble guidance,
expecting 850mb temperatures of 20-21C on Monday and 21-22C on
Tuesday. Any potential convective debris clouds would probably occur
late enough in the day to have too much impact on potential high
temperatures. Highs Monday around 90 along the coast, ranging into
the middle and upper 90s for a good portion of inland areas. Tuesday
a degree or two higher in most cases across the area, with spotty
100 degree readings in NE NJ.

As for dewpoints, both days feature SW-WSW surface winds outside of
locations with an onshore flow. Dewpoints at the top of the boundary
layer are not exactly low enough to have high confidence that
surface dewpoints would lower 5 or so degrees during peak heating,
but then again they`re not prohibitively high either. Pretty good
agreement however that there`s better mix-out potential on Tuesday as
models are showing lower afternoon dewpoints at the top of the mixed
layer as compared to Monday.

No changes to the Heat Advisories for Monday and Tuesday. Heat index
values generally around 100 in the advisory area on Monday. For
Tuesday, heat indices increase by a couple of degrees, with spotty
105 readings in NE NJ, NYC and perhaps in the Lower Hudson Valley.
Not enough coverage and confidence to upgrade to an Excessive Heat
Watch anywhere at this time.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Key points:

* Heat wave likely continues Wednesday with hot and humid
  conditions. Max heat indices in the mid to upper 90s for much of
  the region.

* Showers and thunderstorms develop ahead of a frontal passage late
  Wednesday, bringing the risk of strong to severe thunderstorms and
  heavy rainfall that could lead to flooding into Wednesday night.

* Cooler, drier conditions expected behind the front Thursday
  and into the weekend.

The heat and humidity persists Wednesday before a frontal boundary
moves through Wed night, ushering in a cooler, drier regime late in
the week. Temperatures Wednesday afternoon, while likely a few
degrees lower than Tuesday, still top out in the low to mid 90s away
from the immediate coast. Deep mixing and more of a S/SW low-level
flow should help to transport some slightly lower dew point air to
the surface, so applied CONSALL rather than NBM with this update,
keeping dew points in the upper 60s to lower 70s during time of max
heating. This should still yield max heat indices to once again
approach or exceed 100F in many areas. An extension of the Heat
Advisory appears probable at the moment.

Meanwhile, a digging H5 trough will push a cold front toward the
region late Wednesday and increase convective chances as it does so.
Showers and thunderstorms become likely ahead of the boundary
Wednesday evening and night. As often the case this time of year,
conditions appears conducive for at least the possibility of strong
to severe thunderstorms, as well as torrential downpours given the
deep moisture in place.

The front moves through into early Thursday, and high pressure
begins to build in behind it, with the resulting N/NW flow advecting
in a drier air mass that should knock temperatures down to more
typical values for mid July, generally mid 80s both Thursday and
Friday. Conditions appear to remain dry late this week and
potentially thru the weekend with high pressure remaining in
control.

&&

.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
A frontal boundary dissipates as it drifts east. High pressure
returns later today.

Mostly VFR forecast. However, with the light and variable flow low
stratus and fog is developing along coastal CT and Long Island, and
may expand into early morning, with IFR conditions possible at KGON,
KJFK, KISP, and KHPN. Low chance of brief LIFR, especially at KGON,
and possibly KISP too. Conditions should quickly improve by 13Z,
then VFR thru the remainder of the forecast.

Light and variable into the early morning before a brief period of
northerly winds becomes likely toward 12Z, then becoming S or SW
into early afternoon with speeds at or under 10 kt.

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

Potential IFR ceilings at KJFK this morning. Low chance at KLGA.

Timing of wind shifts may be off by a couple of hours.

OUTLOOK FOR 06Z MONDAY THROUGH THURSDAY...

Late Tonight: VFR.

Monday through Wednesday: VFR. A chance of afternoon into early
evening showers and thunderstorms with MVFR possible at times. SW
wind gusts 15-20 kt afternoon into early evening on Tuesday and
Wednesday.

Thursday: A chance of showers and thunderstorms with MVFR possible.

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

&&

.MARINE...
A marine weather statement has been issued until 9 am this
morning for locally dense fog. Otherwise, winds and seas remain
below SCA criteria through Tuesday night with a relatively weak
pressure gradient in place and lack of a significant swell.

A period of SCA conditions is possible, mainly on the ocean,
Wednesday afternoon and Wednesday night with increased southerly
flow ahead of a frontal passage. Ocean seas may linger at or above 5
ft Thursday before subsiding.

&&

.HYDROLOGY...
No hydrologic concerns are anticipated for today.

Given an abundantly moist air mass in place, any thunderstorms that
develop early to mid next week will have the potential to produce
locally heavy downpours that result in nuisance flooding,
particularly in urban and poor drainage areas.

&&

.TIDES/COASTAL FLOODING...
A high rip current risk continues through this evening for the
beaches of southeastern Suffolk County. A southerly swell of 4 ft 7s
will be slow to subside into Monday. RCMOS and NWPS are generally in
good agreement with the high risk for the far eastern beaches. A
moderate risk can be expected elsewhere.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory from noon Monday to 10 PM EDT Tuesday for
     CTZ005>011.
NY...Heat Advisory from noon Monday to 10 PM EDT Tuesday for
     NYZ067>071-078>080.
     Heat Advisory from noon today to 10 PM EDT Tuesday for
     NYZ072>075-176>179.
     High Risk for Rip Currents through this evening for NYZ081.
NJ...Heat Advisory from noon Monday to 10 PM EDT Tuesday for NJZ002.
     Heat Advisory from noon today to 10 PM EDT Tuesday for NJZ004-
     006-103>108.
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...