895
FXUS61 KOKX 221010
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
610 AM EDT Sat Jun 22 2024

.SYNOPSIS...
A stationary boundary over New England will remain north of the area
through the weekend. A cold front approaches late in the day Sunday
and moves through late Sunday night into Monday morning. High
pressure builds in for Tuesday, and moves offshore Wednesday as
a cold front approaches from the west. The cold front moves
slowly across the region Wednesday night into Thursday morning.
High pressure will return for Thursday night into Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Forecast is generally on track. Patchy fog has developed across
portions of NE NJ, the Lower Hudson Valley, and southern CT.
Some of the fog is dense and a Special Weather Statement has
been issued until 9 am for the patchy dense fog.

The heat and humidity continues to be the main weather story for
this weekend as a frontal boundary remains north of the area and
high pressure remains centered over the northwestern Atlantic.

Continued south to southwesterly flow over the area will continue
the warm advection into the area. Temperatures will be similar to
Friday, as 850 temperatures are also similar to Friday. Highs across
much of NYC should reach the middle 90s, and upper 90s for northeast
NJ. EWR may see 100 once again today. Elsewhere upper 80s to lower
90s are expected across the Lower Hudson Valley and inland southern
CT, while coastal CT and Long Island see highs in the middle to
upper 80s. Combined with dew points in the 70s today, and maximum
heat index values will reach 95 to 104 for much of the area. The
area in and around EWR may see 105 or just above for a maximum heat
index, but think this will be more isolated than widespread for that
part of NJ and opted not to upgrade Heat Advisories to Excessive
Heat Warnings.

Another round of showers and thunderstorms are expected today as a
surface trough develops across western portions of the Lower Hudson
Valley and western New Jersey. CAMs are in pretty good agreement in
location and timing for today, starting across the aforementioned
areas late this morning and moving east through the day.
Additionally, showers and thunderstorms may develop along Long
Island and CT sea breezes. Some of the storms today may become
strong to severe as instability rises to above 1500 J/kg across the
interior this afternoon and 0-6 km bulk shear over 40 kt in some
spots. However, just as the more favorable shear moves into the
region, instability will be on the decrease and mid level lapse
rates do not seem too impressive. SPC has placed the northeast New
Jersey, the Lower Hudson Valley and much of southern CT in a
marginal risk for severe storms, with the primary threats being
damaging winds and large hail, so an isolate severe storm or two is
not out of the question.

Flash flooding is also a possibility with any storms with PWAT
values 1.75" to close to 2".

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
Warm overnight lows expected tonight, with the possibility that some
parts of the metro area may not dip below 80, but for the most part,
looking at lows in the upper 70s here. Lower 70s are expected for
much of the rest of the area. Any showers and thunderstorms will
diminish around and just after sunset with the loss of the
instability.

Slightly warmer temperatures are possible Sunday as models continue
to show 850 temperature rise into the 20-21C range. This will
translate to highs in the middle 90s for NYC, and upper 90s to
possibly just over 100 for northeast NJ. Elsewhere upper 80s to
lower 90s are expected. Given an increasing southerly flow, more in
the way of mixing is expected, which will help to lower dew points
during the afternoon, and despite the fact that temperatures will be
slightly warmer than Saturday, we are still expecting maximum heat
index values to range from 95-104 for the most part. Again, in and
around EWR may see 105+, but it is expected to be isolated.
Therefore, Heat Advisories continue.

The cold front approaches on Sunday, but a prefrontal trough will
move through before the front. This will allow another round of
showers and thunderstorms to move through late Sunday morning and
Sunday afternoon, followed by more rounds of showers and
thunderstorms Sunday night with the cold front. Dynamics may be a
bit stronger as compared for Saturday, but once again instability
looks to decrease as the higher shear values move into the area.

Similar PWAT values continue the possibility of flash flooding as
well.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Key Points:

* Heat wave comes to an end Sunday night-Monday with a cold frontal
  passage.

* One more hot day expected ahead of another frontal system on
  Wednesday.

* A slow moving frontal system could bring locally heavy rainfall
  from late Wednesday into Thursday.

NBM was generally followed, with some adjustments mainly to to
temperatures and dewpoints per 12Z GFS and 00Z ECMWF guidance.

The heat wave should come to an end as an upper trough/closed low
and associated cold front approach the area Sunday night into
Monday. A few tstms with gusty winds possible Sunday evening via pre-
frontal deep layer unidirectional shear (mid layer SW-W flow 35-50
kt) and leftover steep lapse rates from daytime heat. Brief heavy
rain could also be possible with any storms.

Front clears the area daytime Mon, with any 90-plus temps shunted
just south into central NJ, and heat index values close to
actual temps.

Tue should be a bit warmer with high pressure and downslope W-NW
flow in control. High temps will range from 85-90 in most places,
with similar heat index values as afternoon dewpoints should be no
higher than the upper 50s/lower 60s. Wed will be a little warmer and
more humid still, with high temps 90-95 from NYC north/west and the
heat index approaching or just surpassing 95 for one day as
afternoon dewpoints increase to the lower/mid 60s.

A slow moving frontal system should bring an end to this shorter
spell of heat, with chances for tstms from late day Wed into Thu.
More on this in the Hydrology section.

Locally heavy rainfall possible with PW approaching 2 inches and
some potential for training cells along the slow moving frontal
boundary. Attm Fri looks dry with temps near or just above
the seasonal avg.

&&

.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
Key Points:

* Heat wave ends Monday with a cold frontal passage.

* A couple of hot days are expected Tuesday and Wednesday ahead of a
  cold front that moves through Wednesday night into Thursday.

* A slow moving frontal system could bring locally heavy rainfall
  from late day Wednesday into Wednesday night.

No significant changes with this forecast update, with a slightly
slower trend in the cold front Wednesday night into Thursday,
allowing for another hot and humid day Wednesday.

The heat wave ends Monday with a cold frontal passage, and a chance
of showers and thunderstorms continuing until Monday evening, as the
front moves east of the region.

Temperatures rebound Tuesday as high pressure moves off the mid
Atlantic coast and a return flow develops later in the day.
Inland temperatures may once again reach 90 degrees, with heat
indices close to the air temperatures, as dew points will be in the
upper 50s to lower 60s.

With the return flow continuing Wednesday, and a little slower
timing with the approach of another cold front, temperatures will be
several degrees higher than Tuesday, with inland highs in the lower
to mid 90s. Heat indices inland will be in the mid 90s as dew points
climb into the mid 60s.

A slow moving cold front will bring an end to this shorter spell of
heat, with chances for thunderstorms from late day Wednesday into
Thursday morning.

Dry weather returns Friday as another high builds into the region.

&&

.MARINE...
SCA issued for winds and seas on the ocean water Sunday as S-SW flow
strengthens with the approach of the cold front helping to increase
the pressure gradient with the high off shore.
Gusts up to 30 kt possible Sunday afternoon for the ocean, as well
as the south shore bays and the eastern sound zone, where SCAs were
also issued. All other near shore waters are expected to occasional
gust to 25 kt at this time, but this may change with further model
runs.

SW flow 20-25 kt on the ocean with a few higher gusts to 30 kt
Sunday night will maintain significant wave heights of 6-8 ft during
that time frame, and the SCA on the ocean waters goes through Sunday
night because of the elevated wave heights.

A strong SW flow in the morning will be slowly diminishing, and
becoming westerly, as high pressure builds toward the waters. Small
craft conditions, mainly seas, will be on-going on the ocean waters
Monday morning, with seas falling below advisory levels Monday night
as winds become northwest.

Winds and seas across all the waters remain below advisory levels
Tuesday and Tuesday night. SCA conditions will once again become
possible on the ocean waters Wednesday with the approach of another
cold front, as southerly winds increase.

&&

.HYDROLOGY...
Low and localized flash flood threat on today with any slow moving
isolated to scattered tstm activity across interior.

Low flash flood threat late Sunday into Sunday Night with possible
scattered convection development along/ahead of pre-frontal
trough/cold frontal passage.

There is a chance for locally heavy rain from late day Wednesday
afternoon into Wednesday night with a front moving through the
region.

&&

.TIDES/COASTAL FLOODING...
A moderate rip current risk should continue at the ocean
beaches on today via combo of 3-ft SW wind waves and 2-ft long
period SE swell. A high risk is likely for Sunday as S-SW flow
increases to 20 to 25 kt and 5 ft S wind waves increase to 6-8
ft in the afternoon.

Will only mention the high risk in the SRF and HWO and hold off
on rip current statement issuance, to avoid any confusion with
the moderate risk for today.

&&

.CLIMATE...
Here are current record high temperatures thru Sunday...

Saturday, June 22:

NYC: 98(1988)
LGA: 99(1988)
JFK: 94(2012)
EWR: 101(1988)
ISP: 94(2012)
BDR: 93(1949)

Sunday, June 23

NYC: 96(1888)
LGA: 95(1965)
JFK: 94(2010)
EWR: 97(1965)
ISP: 91(1999)
BDR: 91(2010)

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory until 8 PM EDT Sunday for CTZ005>009.
NY...Heat Advisory until 8 PM EDT Sunday for NYZ067>075-176-178.
     Heat Advisory from noon today to 8 PM EDT Sunday for NYZ078-
     177.
NJ...Heat Advisory until 8 PM EDT Sunday for NJZ002-004-006-103>108.
MARINE...Small Craft Advisory from 11 AM to 6 PM EDT Sunday for ANZ332-
     345.
     Small Craft Advisory from 8 AM Sunday to 6 AM EDT Monday for
     ANZ350-353-355.

&&

$$

SYNOPSIS...JP/MET
NEAR TERM...JP
SHORT TERM...JP
LONG TERM...MET
AVIATION...MET
MARINE...JP/MET
HYDROLOGY...JP/MET
TIDES/COASTAL FLOODING...
CLIMATE...