000
FXUS61 KOKX 071626
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1226 PM EDT Thu Sep 7 2023
.SYNOPSIS...
Weak high pressure will be over the region today. A slow moving
frontal system will impact the area tonight through the weekend.
The associated cold front eventually moves east of the region
late Monday, followed by another frontal system for the middle
of the week.
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Forecast still remains on track. Adjusted only for current
observations. Time of initiation for showers and thunderstorms
for areas west and north of the city remains mid/late-afternoon
to early evening based on the latest guidance from 12Z CAMs.
Some record high minimum temperatures could occur for today
provided temperatures later this evening do not cool more
quickly than anticipated. Biggest reason for a quicker cooldown
would be rain. See the climate section below for the records.
The region will be on the western side of a mid level ridge today.
After a mostly sunny start, more in the way of clouds this afternoon
mainly W and NW of NYC as convective debris clouds may drift into
the area by day`s end. CAPES will be sufficient to support
convective development over the region - again mainly W and NW of
the city, however low to mid-level capping probably limits this to
scattered activity. Not much mechanical lift to tap into CAPE until
this evening when a shortwave aloft is progged to pass by not too
far to our NW. CAPES will be lower by this time, but still plenty
enough to continue the threat of showers and thunderstorms well into
the night.
Regarding the severe weather potential, shear isn`t
particularly ideal, but a little stronger this evening with the
shortwave nearby. It`s enough however to support strong to
severe wind gusts. Large hail cannot be completely ruled out
with sufficient cape in the -10 to -30C region through this
evening, however directional shear appears to be lacking and
wet-bulb zero heights will be on the high side. SPC continues to
highlight areas W and NW of the city with a slight risk for
severe weather today with a marginal risk for the rest of the
area except eastern LI and SE CT.
It will be another hot and humid day. Although temps at the top
of the mixed layer rise slightly from yesterday, an earlier
onshore flow probably keeps temps from reaching as high as they
did yesterday for most coastal areas. Farther inland, it may
even be hotter than yesterday in some areas, especially if
convection can hold off until late in the day and/or convection
to the west doesn`t send a significant amount of debris clouds
our way. Surface dewpoints will have a tough time mixing out
this afternoon - whether it be because of seabreezes at the
coast or SW flow with high dewpoints (14-17C) at 850mb inland.
Heat advisories pertaining to today remain unchanged from the
previous forecast with the exception of adding Western Passaic
County based on yesterday`s observations and today`s forecast.
The heat advisory has been extended to include Friday for some
areas. See the short term section for more details. While max
heat indices probably end up even higher than yesterday in most
areas, they are expected to remain within the advisory
threshold.
Warm and muggy conditions continue tonight with a chance of
record high minimum temperatures being set.-- End Changed Discussion --
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Surface high pressure builds to our east while under a ridge
aloft. To our NW, confluence aloft will promote high pressure
building over the Great Lakes. We`ll be in between with surface
troughing over us. Moisture convergence along and near this
trough will promote primarily diurnal showers with a chance of
thunderstorms. Once again, thunderstorms can be strong to severe
with the main threat being gusty winds as 0-6km bulk shear will
be 25-30 kt. SPC has most of the city and areas N and W of the
city with a slight risk for severe weather, and a marginal risk
for the rest of the area.
More clouds and cooler temperatures aloft will promote high
temperatures cooler than the past few days, however dewpoints
will be in the mid 70s. This should manage to produce heat
indices of at least 95 degrees for NE NJ, NYC, as well as
Rockland and Westchester Counties. As such, heat advisories have
been extended in time to cover through Friday afternoon.
The pattern doesn`t change much on Saturday with a trough and
enhanced moisture convergence over the region. Showers will be
more likely in the afternoon and night along with the threat of
a thunderstorm. Overall higher chances will be from around the
city to points N and W where moisture convergence will be
greater in the vicinity of the surface trough. The flash
flooding threat through Saturday remains low. See the hydrology
section for more details.
Mostly cloudy conditions should hold high temperatures in the
80s across the area, but dewpoints will still be in the low to
mid 70s. If this holds, then heat advisories wouldn`t need to be
extended into Saturday.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
The main story during the long term period will be the
unsettled weather Sunday into Monday, then again during the
middle of the week.
The long term period starts off with a nearly stalled cold
front over the far western portion of the CWA. This front won`t
move much during the day, with a wave of low pressure traveling
along its boundary. The front finally starts to move eastward
during the day Monday as an upper level shortwave approaches
from the west. The front should finally move east of the region
sometime late Monday evening or overnight.
Still thinking that Sunday and Monday wont be a complete
washout and it will not be raining the whole period. The timing
of any individual piece of energy and associated lift is
uncertain, but have gone with the more usual diurnal timing for
higher probabilities. Portions of Long Island and southern
Connecticut may not see any convection until late Sunday or even
early Monday.
Localized heavy rainfall is possible in any of the
shower/thunderstorm activity with any flash flood potential
remaining localized.
Some drier air will finally move back into the region on
Tuesday, however there is a second frontal system on its heels
with an amplifying upper trough digging south and east across
the Great Lakes. Chances for convection will be on the increase
ahead of this system late Tuesday into Wednesday, perhaps
lingering into Thursday.
Highs on Sunday through Tuesday will be in the Upper 70s and
lower 80s, with cooler conditions on Wednesday and Thursday as
highs only reach the 70s.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
High pressure remains offshore, meanwhile an upper level trough
and cold front slowly approach from the west.
VFR conditions until late tonight, after 08Z, when MVFR fog is
possible, and there is a chance of MVFR stratus as well,
however, confidence is low.
Timing of any showers/thunderstorms is now a few hours later,
with the best chances at KSWF, 23Z to 03Z. Removed the VCSH
from the NYC terminals with low chances of any precipitation
occurring.
Light and variable winds become S/SW 5-7kt this morning, then
S/SE sea breezes 8-12kt for all coastal terminals in the
afternoon and evening. Winds become light once again tonight
night.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Winds could be slightly higher than forecast this afternoon and
evening at JFK/LGA with coastal jet development. If any
showers/thunderstorms occur, now looks to be this evening, after
00Z, however, chances are less than 20%.
OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
Friday: Chance of aft/eve showers and thunderstorms,
particularly NYC and points N&W. MVFR/IFR coastal stratus
possible Friday Night.
Saturday through Sunday: Aft/Eve showers and thunderstorms
likely, particularly NYC and points N&W on Sat and Sun.
Increasing potential for nocturnal/early morning MVFR/IFR
coastal stratus.
Monday: Possible early morning MVFR/IFR coastal stratus. Chance
of showers and thunderstorms.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
A weak pressure gradient will lead to sub SCA conditions for the
rest of the week. Winds and seas will remain below SCA levels
for the weekend despite the approach of a slow moving cold
front.
Ocean seas are forecast to build to 5 ft early next week and may
continue for much of the week. For the non-ocean waters, sub SCA
conditions will continue.
&&
.HYDROLOGY...
Locally heavy rain is possible today with isolated/scattered
thunderstorms. Should any flooding occur, it would likely be
limited to minor/nuisance/poor drainage flooding. Can`t
completely rule out flash flooding west of the Hudson River, but
this would likely be isolated.
For Friday and more so Saturday, flooding chances increase, but
again would be of the minor type. Flash flooding would again be more
likely to occur along and west of the Hudson River corridor as rain
chances increase and slower-moving cells/training cells become more
likely. This threat then spreads east to cover more the Tri-State
Area on Sunday.
&&
.TIDES/COASTAL FLOODING...
A moderate risk of rip currents exists today with lingering ESE
swells and a stronger S flow developing in the afternoon. The strong
south flow continues on Friday which likely builds seas to 3 ft.
Swells may still linger, so have gone with a moderate risk of rip
currents on Friday.
&&
.CLIMATE...
Some daily record highs and record high minimums could be tied or
broken early this morning, today and tonight. The records are below.
Daily Record High Temperatures...
Sep 7
Central Park..101(1881)
LaGuardia.....90 (2015)
JFK...........93 (1983)
Islip.........92 (1998)
Newark........95 (2015)
Bridgeport....91 (1983)
Daily Record High Minimum Temperatures...
Sep 7 Sep 8
Central Park..79 (1881)..76(2015)
LaGuardia.....74 (2012)..76(2015)
JFK...........76 (1985)..73(1983)
Islip.........74 (2012)..76(2015)
Newark........74 (1999)..73(1999)
Bridgeport....72 (2016)..74(2015)
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory until 8 PM EDT this evening for CTZ005>010.
NY...Heat Advisory until 8 PM EDT this evening for NYZ067-068-078-
080-177-179.
Heat Advisory until 6 PM EDT Friday for NYZ069>075-176-178.
NJ...Heat Advisory until 6 PM EDT Friday for NJZ002-004-006-103>108.
MARINE...None.
&&
$$
SYNOPSIS...BC/JC
NEAR TERM...JC/BR
SHORT TERM...JC
LONG TERM...BC
AVIATION...MET
MARINE...JC
HYDROLOGY...BC/JC
TIDES/COASTAL FLOODING...
CLIMATE...