809
FXUS61 KOKX 182347
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
747 PM EDT Tue Jun 18 2024
.SYNOPSIS...
High pressure over the western Atlantic remains in control
through late this week. A cold front moves in from northwest
on Friday and stalls over the area to begin the weekend. The
front then moves back north as a warm front on Sunday. A more
potent cold front approaches for Monday and moves through Monday
night. High pressure returns on Tuesday.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
-- Changed Discussion --
Upper level anticyclone/ridging continues to build aloft
tonight with high pressure over the Western Atlantic. Any
convection to the west and northwest has difficulty surviving
with increasing subsidence. The building heights and mid level
cap will prevent this activity from organizing and moving into
western and northwestern portions of the area. Therefore it will
be dry and warm tonight. Dew points have been running a degree
or two higher from earlier, but expecting them to mix out a bit
into the lower 60s throughout this evening and tonight as
subsidence and some drier air advects north around the surface
high. Lows will be in the middle to upper 60s for most spots
with some low 70s in the NYC metro.-- End Changed Discussion --
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
-- Changed Discussion --
Heat Advisories remain in effect across NE NJ, the Lower
Hudson Valley, and interior CT through Thursday evening.
*Key Messages*
*Heat wave is expected to continue through at least Thursday,
but model guidance has continues to trend down a bit in recent
cycles with temperatures and dew points.
*Temperatures across NE NJ, Lower Hudson Valley, and interior
CT reach the lower and middle 90s with heat indices 95 to 98.
Most places should remain below 100 for max heat index both
Wednesday and Thursday.
*Temperatures in the NYC metro should reach 88-93, highest on
Thursday. Peak heat index values in NYC metro now look to be
91-94 on Thursday with some isolated areas touching 95. Due to
limited coverage of reaching 95, have held off on expanding
the heat advisory into the NYC metro.
*Onshore flow will keep much of Long Island and coastal CT a bit
cooler both Wednesday and Thursday. Highs should top out in the
middle to upper 80s with heat indices around 90. Portions of
NW Long Island may be a bit warmer, but should fall short of 95
heat index.
The core of the upper anticyclone/ridge will set up right over
the region on Wednesday. A general consensus of the latest
guidance indicates 500 mb heights will peak around 596dm-598dm
Wednesday into Wednesday night, which is close to the observed
max for KOKX per the SPC Sounding Climatology. However, the
highest temperatures and dew points look to remain north of the
area due to the orientation of the flow around the upper
anticyclone. The center of the anticyclone will start to shift
to the south and west on Thursday, but more so Thursday night
into the end of the week.
The NBM has continued to shrink the spread in the temperature
distribution for both Wednesday and Thursday with the
deterministic nearly the 50th percentile for both days. This
has led to increased confidence that the current heat advisory
looks good with locations across NE NJ, Lower Hudson Valley, and
interior CT reaching the lower to middle 90s and heat indices
in the mid to upper 90s. Onshore flow likely holds temperatures
down just enough over much of the NYC metro and coast to prevent
heat indices from reaching 95 on Wednesday. In fact, highs for
the NYC metro have trended down and could struggle to exceed 90
on Wednesday.
Similar concerns are present on Thursday. While actual air
temperatures may rise another few degrees from Wednesday, they
still have lowered in the NBM with much smaller spread. Dew
points should be a bit higher, but not seeing widespread upper
60s and lower 70s to help push max heat indices into advisory
levels for the metro. Higher temperatures for NE NJ and inland
areas in combo with middle to upper 60s dew points will help
heat indices reach the middle to upper 90s supporting the
ongoing Advisory. It looks like the higher dewpoint/humidity air
will begin pooling to our north along an approaching front from
the north on Thursday, but any convection should remain outside
of the area.-- End Changed Discussion --
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
**Key Points**
* Heat wave will likely be broken up to some degree Friday and
Saturday, but still quite warm and humid. The chances for showers
and thunderstorms has increased for the second half of Friday into
a portion of Saturday.
* Sunday looks to likely be the hottest day with more widespread
heat and humidity.
* The humidity gets broken late Monday into Tuesday, with a round of
showers and thunderstorms.
The latest trend of note in the numerical guidance is a trending
further south of a cold front into our area during Friday and into
the early portion of the weekend. NWP global guidance and some of
the short range guidance like the RGEM point to a cold front sagging
further south now, with QPF and reflectivity output pointing towards
showers and storms for Friday afternoon and evening. With PWATs
rather high, 1.75 to 2 inches any storms to begin the period could
produce locally heavy rainfall as a cold front sags south and likely
stalls to some degree into Friday evening / night. See hydro section
for further details. With the front nearby and the area still not
out of the humid air mass on Saturday look for more showers and
storms to fire up and likely be scattered across the area. Not a
wash out, but in and out of sun and clouds with scattered convection
still being a good bet.
By Saturday night into Sunday morning thickness ridging is indicated
by the consensus of the guidance. This should lead to the warm front
lifting north and putting our areas purely in the warm sector. 5kft
temps are progged by global NWP to get to around 19-20 C. If this
transpires on more of a lower level SW flow Sunday looks to be the
warmest day of the heat spell in terms of widespread 95 heat
indices. Interior portions of the area and possibly the metro could
very well see heat indices between 100 and 105 given the warm front
getting well to the north. Questions remain around the timing of a
lead shortwave / pre-frontal trough ahead of the main mid / upper
level shortwave feature for late Sunday. Thought it prudent to at
least carry chance PoPs, especially further NW for later Sunday as
things destabilize through the day. The primary threats for any
storms later Sunday would likely be strong winds and heavy rain. The
main shortwave / trough then pivots through into Monday as a
stronger cold front pushes through with the ongoing chance of
convection. By Monday night into Tuesday things should improve from
west to east, with less humid conditions with clearing skies. It
will still be quite warm on Tuesday with increased mixing and
downsloping on a westerly component to the wind, but the humidity
should be lower.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
High pressure remains in place based in the Western Atlantic
through midweek.
VFR conditions will remain in place through the TAF period with
winds remaining from the south to southwest.
Winds will be near 8-12 kt early this evening with some gusts
for NYC terminals and KISP to near 20 kt. Winds overall will be
near 4-8 kts late this evening, overnight, and into early
Wednesday with no gusts. Winds further increase Wednesday
afternoon to near 10-12 kt with gusts up to 20 kt mainly for NYC
terminals and some other terminals outside of NYC.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of gusts could be 1-2 hours off from TAF.
OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...
Wednesday night and Thursday: VFR. S-SW wind gusts 15-20 kt
early Wednesday evening before diminishing. S-SW wind gusts
15-20 kt for Thursday afternoon into early Thursday evening as
well.
Friday thru Sunday: Potential for MVFR or lower conditions in
showers and thunderstorms, mainly in the afternoon/evening
hours. For Sunday afternoon into early Sunday evening, S-SW wind
gusts 15-20 kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
-- Changed Discussion --
Strong S flow due to earlier sea breeze circulations push wind
gusts occasionally to around 20-25 kt nearshore across the NY
Harbor and the western most ocean waters into this evening and
then again both Wednesday and Thursday afternoons. Otherwise,
conditions will remain below SCA levels through the end of the
week.
Sub small craft conditions will continue through Friday night with a
S to SW wind. As a cold front moves nearby and perhaps over the
waters the winds will likely be more out of the SE for Saturday with
ocean seas getting closer to 4 ft. Marginal small craft seas for the
ocean waters are then expected Saturday night into Sunday. Marginal
small craft gusts are then possible for the ocean waters during
Sunday afternoon.-- End Changed Discussion --
&&
.HYDROLOGY...
A cold front will bring scattered showers and t-storms for Friday
and possibly Friday night. Some storms could linger, although likely
won`t be as widespread on Saturday. Any stronger storms will likely
produce locally heavy rainfall with a low risk of localized flash
flooding. This will depend on the speed of the storms which is too
early to assess at this time. Another round of storms is possible
late Sunday and again into Monday with uncertainty around potential
hydrologic impacts.
&&
.TIDES/COASTAL FLOODING...
There is a moderate rip current risk for the western ocean beaches,
and a low rip current risk for the Suffolk ocean beaches on
Wednesday. There will be a moderate rip current risk for all ocean
beaches on Thursday.
&&
.CLIMATE...
Here are current record high temperatures for Wednesday through
Friday.
Wednesday, June 19
NYC: 98(1994)
LGA: 97(1994)
JFK: 98(1994)
EWR: 102(1994)
ISP: 96(1994)
BDR: 96(1994)
Thursday, June 20
NYC: 98(1923)
LGA: 98(2012)
JFK: 94(2012)
EWR: 98(2012)
ISP: 93(1995)
BDR: 93(1953)
Friday, June 21
NYC: 97(1988)
LGA: 98(2012)
JFK: 97(2012)
EWR: 100(1953)
ISP: 95(2012)
BDR: 96(2012)
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory until 8 PM EDT Thursday for CTZ005-006.
Heat Advisory from noon Wednesday to 8 PM EDT Thursday for
CTZ007-008.
NY...Heat Advisory until 8 PM EDT Thursday for NYZ067>070.
NJ...Heat Advisory until 8 PM EDT Thursday for NJZ002-004-006-
103>108.
MARINE...None.
&&
$$
SYNOPSIS...JE/DS
NEAR TERM...JE/DS
SHORT TERM...DS
LONG TERM...JE
AVIATION...JM
MARINE...JE/DS
HYDROLOGY...JE/DS
TIDES/COASTAL FLOODING...
CLIMATE...