Area Forecast Discussion
Issued by NWS Upton, NY-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KOKX 290002
Area Forecast Discussion
National Weather Service New York NY
802 PM EDT SUN AUG 28 2016
High pressure along the New England and Mid Atlantic coasts will
move east tonight, while a cold front approaches from the Great
Lakes. The front will work slowly across Monday, then high
pressure will build in Monday night into Tuesday. The high will
give way to a cold front late Wednesday into Wednesday night,
followed by high pressure for the end of the week and into next
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
High amplitude ridge centered across the Mid Atlantic and nearby
atlantic will flatten as an upper trough moves across southern
Canada overnight and into New England on Monday. This will allow
a cold front to approach. Model guidance looks too aggressive
with high and mid level cloud cover overnight, and have trimmed
back through this evening, with mostly clear skies expected until
after midnight when deeper low level moisture starts to arrive.
Even then, forcing looks weak with the main troughing only just
entering northern New England by 12Z Mon, so only bring in mostly
cloudy skies and slight chance for a shower late tonight NW of NYC
and across southern CT.
Low temps per MOS guidance blend will be in the lower 70s in NYC,
and in the 60s elsewhere.
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Cold front will move slowly across Monday morning, with morning
clouds and only slight chance of an early shower, then likely get
hung up right along the coast until late afternoon. Post-frontal
downslope WNW flow will clear skies out during the late morning
and afternoon and allow temps to be quite warm throughout, with
lower 90s in many places all the way down to the coast, a little
higher than the warmest of the GFS/NAM MOS guidance. The air mass
will remain relatively dry, so heat index values will be close to
actual air temps.
High pressure will build in from the NW Monday night, with mostly
clear skies. Lows Mon night will range from the lower 70s in NYC,
to the 60s most elsewhere, to 55-60 in the interior valleys and
the Long Island Pine Barrens.
There is a moderate risk for rip current development across the
ocean beaches of Nassau, Queens and Brooklyn, and a high risk for
rip current development across Suffolk ocean beaches as long
period SE swells from distant tropical cyclone Gaston build to 3
to 4 ft. Breaking surf in the 3-5 ft range could occur as well.
.LONG TERM /TUESDAY THROUGH SUNDAY/...
As ridge resides well to the west, upper trough approaches the
northeast Wednesday and Thursday, with its axis passing east by
Friday. Ridging then builds behind it.
Surface high pressure early in the period will give way to
approaching cold front Wednesday night. This front moves east
Thursday as high pressure builds behind providing plenty of
sunshine and dry weather through the weekend.
A dry period is expected, with best chance for rain occurring along
and ahead of the front late Wednesday-Wednesday night and into
Due to ample support aloft, and consistent model output of precip,
feel scattered activity looks like a good bet mainly Wednesday
Seasonable or slightly above seasonable temperatures Tuesday will
warm ahead of the front Wednesday, averaging at least 5 degrees
above normal. Then temperatures settle back closer to or just below
seasonal norms behind the front late this week. Some moderating in
temps likely next weekend.
The threat for rough surf and high risk for rip current development
should continue through the mid to late week due to SE swells
from distant Hurricane Gaston.
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --VFR with high pressure in control. A weak cold front approaches
tonight and slowly crosses on Monday.
Light S/SE winds overnight, shifting to the SW late tonight, then
W by Monday afternoon. There is a low chance that wind direction
could be closer to 310 magnetic during the afternoon. Better
chances of directions right of 300 magnetic Monday evening. Gusts
of 15-20 kt in the afternoon, with an isolated gust in the lower
20s kt range possible, mainly for the city and some coastal terminals.
.Outlook for 18Z Monday through Friday...
.Monday Afternoon...Mainly VFR. Winds may average just to the
right of 310 magnetic, with gusts to 15-20 kt possible. Low prob
of an isolated shower.
.Wednesday Night-Thursday Morning...Showers/tstms possible with
-- End Changed Discussion --
Ocean seas will continue to slowly build in response to long
period swells generated by distant Hurricane Gaston. There is a
low chance that the combination of wind waves generated by 15-kt
WSW flow and these incoming swells could bring ocean seas up to 5
ft on Monday, but since NWPS guidance has tended to run high with
seas, capped max seas at 4 ft through Monday night, which is in
agreement with Hurricane WaveWatch guidance.
From Tuesday through Thursday, and possibly into Friday, ocean seas
will remain elevated due to long period swells generated by Gaston.
The non-ocean waters should remain rather tranquil, although it
could get a little rough as some of the ocean swells make it into
the extreme eastern portion of Long Island Sound and western Block
Winds should remain below SCA criteria, although they will increase
on Wednesday ahead of an approaching weak cold front. Gusts on a
northerly wind flow are also anticipated as the waters sit
between the departing front, and high pressure building late
Thursday and Thursday night.
No significant widespread precipitation is expected.
NY...High Rip Current Risk from 6 AM EDT Monday through Monday
evening for NYZ080-081.