000
FXUS61 KOKX 052228
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
628 PM EDT Tue Sep 5 2023
.SYNOPSIS...
High pressure remains in control through Wednesday. The high begins
to weaken on Thursday. A slow moving frontal system will impact
the area Thursday night through the weekend. The associated
cold front passes through late Sunday night into Monday.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
-- Changed Discussion --
Forecast remains on track this evening. Sea breeze has been slow
to develop, but has started inching north across eastern Long
Island and coastal CT. Temperatures will gradually cool after
sunset after a hot afternoon. Mostly clear skies are expected
tonight as high pressure remains a strong influence in the
region. Warm and muggy conditions will prevail with widespread
lows in the low/mid-70s.-- End Changed Discussion --
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
An upper level ridge will remain over the area through mid-
week, resulting in temperatures around 10 degrees above average.
Heat advisories will be in place for NE NJ and the NYC metro
Wednesday and Thursday for heat indices between 95 and 98 degrees.
Nassau and western SUffolk will be added to the heat advisory
Wednesday only. Interior sections of CT will be under a heat
advisory both Wednesday and Thursday. It looks like the upper-
level ridge leading to the anomalous heat will reach its peak
strength Wednesday with temperatures expected to be a degree or
two warmer across the board Wednesday compared to Tuesday.
The upper level ridge starts to weaken and slide east Thursday.
Despite this, strong heat will remain in place Thursday afternoon.
Record high temperatures are possible on Wednesday and Thursday for
some climate sites. Record maximum lows are also possible for some
climate sites Wednesday and Thursday night. You can reference the
climate section of this AFD for a listing of prior records.
Isolated showers and/or thunderstorms are possible for western
interior portions of our area Thursday night from a weak frontal
system, but confidence is low on if they will occur.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
The large upper level ridge that has been bringing the recent heat
to the region will continue shifting to the Western Atlantic
Thursday night into Friday. An upper trough/shortwave will also
slowly approach into the weekend. The trough appears to help amplify
the ridging again offshore, which slows down the overall progression
of the system. As a result, the guidance has been trending towards
slowing down the associated cold front over the last few days. There
is also a complex interaction of several different vorticity maxima
within the trough, with one area potentially cutting off across the
southeast this weekend.
Heights should begin to fall Thursday night and a pre-frontal trough
will likely be in the vicinity. The degree of lingering ridging
aloft should play a roll in whether capping aloft will break down
and support some scattered convection across the interior Thursday
evening. The GFS profiles show the cap breaking down, but the NAM
still holds onto a cap between 700 and 800 mb. Larger scale forcing
is absent, but the pre-frontal trough could serve as a focus. Any
convection that develops Thursday evening should diminish overnight.
The frontal system will be closer to the western part of our CWA on
Friday. The close proximity of the ridge offshore may still play a
roll in how much convection develops into the afternoon and evening.
Have capped PoPs off at chance and mainly north and west of the NYC
metro. There are similar differences noted with forecast soundings
with the NAM holding onto capping aloft vs the GFS with no cap. The
majority of the lift from the aforementioned upper trough will also
remain well to the west. The bigger story on Friday may end up being
another day of heat and humidity. Temperatures should be a few
degrees cooler than earlier in the week, but humidity levels will
remain high. The latest model consensus has highs in the upper 80s
for most locations. The slightly cooler temperatures are a result of
a stronger onshore flow. If the onshore flow is a bit weaker,
especially early in the day, highs could end up a few degrees
higher. This is shown with NBM 90th percentile highs across NE NJ
reaching the lower 90s. Max heat indices are forecast to be in the
upper 80s to low 90s, but some parts of NE NJ could still touch 95.
The frontal system should remain nearly stationary over or just west
of the area this weekend. This would normally bring concern for
potential of locally heavy rainfall and training convection.
Given the models struggling with interactions of different vorticity
maxima and the amplification of the trough, have gone more
conservative with PoPs and resulting sensible weather at this time.
There will likely be more cloud cover this weekend, which could
impact the amount of instability. PoPs are currently higher on
Saturday with likely (60%) north and west of NYC metro and chance
elsewhere and chance areawide on Sunday. The 12z modeling has shown
the upper trough flattening on Sunday, with little change in the
height field over the region. The remaining part of the shortwave
trough is progged to push through by Monday morning which should
help move the front to the east. However, this is a week out and it
would not be out of the question if the front weakened or washed out
given the ridging over the Western Atlantic.
Temperatures still look to be cooler this weekend given the
increased cloud cover and chances for precipitation. Have followed
the NBM closely Saturday through early next week. This yields highs
in the 80s on Saturday, in the upper 70s to around 80 in Sunday and
Monday. Humidity levels remain elevated this weekend, but there may
be some relief early next week. This will all be dependent on if the
cold front can fully move to our east.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
-- Changed Discussion --
High pressure will remain in control through midweek with thermal
troughs setting up across the area each afternoon.
VFR. A light N to NW flow of less than 10 kt. Seabreeze boundary
will move north through KJFK and KISP thru 23z. It may make it
to KLGA, KEWR, and KTEB in a weakened state around/after 00z.
Winds tonight will once again become light and variable or
light northerly. Sea breezes are possible again Wednesday.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Light S/SE sea breeze may make it into KLGA/KEWR/KTEB after
00z.
OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...
Wednesday: VFR.
Thursday: Mainly VFR. Chance of late afternoon/evening showers and
thunderstorms for the NYC and Lower Hudson Valley terminals.
A slight chance elsewhere.
Friday through Sunday: MVFR possible at times in round of showers
and thunderstorms. S wind gusts 15-20 kt Friday.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Sub-SCA conditions are expected through Thursday.
A slow-moving frontal system approaches Thursday night into the
weekend. Winds and seas are expected to remain below SCA levels
during this time period.
&&
.HYDROLOGY...
-- Changed Discussion --
No hydrologic impacts are expected through Thursday.
Locally heavy rainfall is possible Friday into the weekend, but
there is still too much uncertainty with the timing and extent
of the activity.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
A moderate risk of rip currents continues into this evening at ocean
beaches. Have gone with a moderate risk of rip currents at all ocean
beaches on Wednesday as long period ESE swells of 3 ft to 10-11s
look to continue. The swells may diminish Thursday, but given a
stronger southerly flow in the afternoon and lingering 9 second
periods, have forecast a moderate for now at all ocean beaches.
&&
.CLIMATE...
Some daily record highs and lows could be tied or broken over the
next couple of days. The record highs for these dates are below.
Daily Record High Temperatures...
Sep 6 Sep 7
Central Park..97 (1881)..101(1881)
LaGuardia.....96 (2018)..90 (2015)
JFK...........92 (1985)..93 (1983)
Islip.........90 (1985)..92 (1998)
Newark........98 (2018)..95 (2015)
Bridgeport....92 (2018)..91 (1983)
Daily Record High Minimum Temperatures...
Sep 6 Sep 7 Sep 8
Central Park..78 (1985)..79 (1881)..76(2015)
LaGuardia.....79 (1985)..74 (2012)..76(2015)
JFK...........77 (1985)..76 (1985)..73(1983)
Islip.........79 (1985)..74 (2012)..76(2015)
Newark........77 (1985)..74 (1999)..73(1999)
Bridgeport....75 (1985)..72 (2016)..74(2015)
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory from 11 AM Wednesday to 8 PM EDT Thursday for
CTZ005>008.
NY...Heat Advisory from 11 AM Wednesday to 8 PM EDT Thursday for
NYZ068-070.
Heat Advisory until 8 PM EDT Thursday for NYZ067-069-071>075-
176-178.
Heat Advisory from 11 AM to 8 PM EDT Wednesday for NYZ078-080-
177-179.
NJ...Heat Advisory until 8 PM EDT Thursday for NJZ004-006-103>108.
MARINE...None.
&&
$$
SYNOPSIS...BR/DS
NEAR TERM...BR
SHORT TERM...BR
LONG TERM...DS
AVIATION...JP
MARINE...BR/DS
HYDROLOGY...BR/DS
TIDES/COASTAL FLOODING...
CLIMATE...