000
FXUS61 KOKX 121815
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
215 PM EDT Tue Sep 12 2023
.SYNOPSIS...
A frontal system will approach late today and move across on
Wednesday. High pressure will build in behind the departing cold
front, remain over the Great Lakes through Friday, then weaken
over the weekend. At the same time, Hurricane Lee is forecast to
pass offshore to our east. A frontal will system approach for
early next week.
Monitor https:/www.weather.gov/okx/tropical or
https:/www.nhc.noaa.gov for the latest NHC forecasts on Hurricane
Lee and others.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
Lowered clouds for eastern parts of the region but not as much
for Southeast CT. Forecast slightly adjusted with temperatures
and dewpoints to better match with observed trends. Sea breeze
convergence leading to more clouds in Southeast CT with some
rain showers probable as well going into late this afternoon as
indicated by some CAMs. Forecast mainly on track.
In the mid levels, the area will be on the northwest side of a
ridge with negative vorticity advection. Some warmer
temperatures aloft are also forecast from forecast BUFKIT
soundings. At the surface, the local region will be in between
low pressure areas today. A frontal system approaches from the
west late today. The environmental conditions will result in a
mainly dry day with much less shower coverage compared to the
previous day.
Generally westerly flow at the surface becomes more southerly
this afternoon. Also, in Southeast CT, multiple CAMs are
indicating shower development with their reflectivity forecasts.
With warmer temperatures aloft, this should provide enough
capping to preclude thunder, so left out thunderstorms in the
forecast but do have low chances of showers for mainly Southeast
CT where there is more low level convergence.
Overall, forecast highs are anticipated to be in the upper 70s
to lower 80s.-- End Changed Discussion --
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
An upr low approaching Lake Superior will drive a strong h5 trof
towards the area tngt and Wed. As heights fall, pcpn will
increase from the west early Wed mrng, spreading ewd thru the
day. Moisture transport will bring pwats close to 2 inches on
Wed, setting the stage for locally hvy rainfall and the
potential for some flooding. Best convergence is expected to be
across the wrn 2/3 of the cwa attm, so this area has been
highlighted in the hwo for flooding. A watch may need to be
issued. Elsewhere, although some isold flooding cannot be ruled
out, the primary threat looks to be the potential for strong
winds and even an isold weak tor in the strongest cells. Warm
ssts, a mdt sly onshore flow along with some llvl shear are
often a recipe for pockets of svr. This threat has been
mentioned in the hwo for all areas, although the ern 2/3 of the
area appear to be favored in this scenario attm.
Made some local adjustments to the NBM and used for temps thru
the period.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
The svr/flood threat persists into Wed ngt, mainly the ern half
of the cwa ahead of the cold front. The rain tapers off behind
the front, but the NAM suggests some post-frontal redevelopment
with the rr quad of the jet during the first part of Thu. The
NBM has not caught on to this probability yet, and the 00Z GFS
and ECMWF both keep Thu dry, so did not go with the wetter NAM
attm. This is subject to change through.
Dewpoints in the 40s and 50s advect in on nwly flow Thu and Thu
ngt producing a notable airmass change thru Fri.
For the weekend, NBM pops clip the far ern portion of the CWA on
the periphery of Lee. Otherwise, fair weather can be expected.
WAA starts Mon and Tue, so some chances for a few shwrs. The NBM
with local adjustments was used.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
-- Changed Discussion --
A cold front approaches tonight and moves across the terminals
on Wednesday.
Generally looking at VFR conditions for the remainder of the
afternoon and evening. Tonight, we start off VFR and should
remain VFR for much of the night, until conditions fall to MVFR
or lower in chances of rain around 08-10z. Hi-res forecast
guidance showing line of showers and thunderstorms moving
through the terminals during the morning push (11-14z) and have
included a tempo to cover this threat. Lesser confidence of
thunder after 14z, but still can not rule out some leftover
convection, will continue with a PROB30 from 14-18z to address
this threat. Timing of convection will be slightly later for the
terminals east of NYC.
Winds gradually shift to the south during the afternoon as sea
breezes develop, then the synoptic flow turns more southerly and
remains light overnight. Winds are expected to become more
westerly then northwesterly behind the front on Wednesday,
mainly after 18z.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of wind direction changes may be off by an hour or two.
Amendments may be needed to fine tune timing of thunder on
Wednesday.
OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...
Wednesday: Any leftover Showers and/or thunderstorms taper off,
with a return to VFR for any terminals below VFR conditions.
Thursday - Friday: VFR. Northerly wind gusts around 15 to 20 kt
Thursday night through Friday night.
Saturday: Mainly VFR. NW wind gusts around 20 to 25 kt.
Sunday: VFR. West winds with gusts 15-20kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Seas will continue to build thru the week due to Lee. A sca has
been issued for the ocean Wed as seas hit 5 ft. Seas will remain
abv 5 ft thru at least Fri, and potentially thru the weekend
depending on the exact track and timing of Lee. Unless there is
a dramatic shift from the current official fcst for Lee, winds
are expected to peak at around 30 kt on the ern waters Fri into
Sat. Conditions improve on Sun.
&&
.HYDROLOGY...
Around an inch of rain is expected for most areas Wed and Wed
ngt. Locally heavier amounts are likely. Areas of minor
flooding can be expected. There is also a chance for flash
flooding, particularly across the wrn 2/3 of the area. Rainfall
rates of over an inch per hour will enhance the threat. A flood
watch may be needed.
There is a chance for another round of heavier rain early Thu,
which if it occurred would produce an additional minor flood
threat. This is a low probability scenario attm, and has not
been included in the fcst attm.
&&
.TIDES/COASTAL FLOODING...
There is a moderate rip current risk today, then a high risk
thru the rest of the week as swell continues to build. A high
risk statement has been issued thru Fri, and may need to be
extended thru at least Sat depending on the ultimate track,
intensity and timing of Lee.
A high surf advy may be needed Fri.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Risk for Rip Currents from Wednesday morning through Friday
evening for NYZ075-080-081-178-179.
NJ...None.
MARINE...Small Craft Advisory from 6 AM Wednesday to 6 AM EDT Thursday
for ANZ350-353-355.
&&
$$
SYNOPSIS...JMC
NEAR TERM...JM
SHORT TERM...JMC
LONG TERM...JMC
AVIATION...BC
MARINE...JMC
HYDROLOGY...JMC
TIDES/COASTAL FLOODING...