Area Forecast Discussion
Issued by NWS Upton, NY-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KOKX 251537
Area Forecast Discussion
National Weather Service New York NY
1137 AM EDT THU AUG 25 2016
High pressure will remain to the south today. A weakening front
will approach tonight, then move across on Friday, followed by
high pressure this weekend. A cold front will approach early next
week, and may then linger nearby through Wednesday.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Forecast is on track. High pressure will remain anchored offshore
while an upper level disturbance approaches from the west. Expect
high and mid level clouds to increase mainly NW of NYC into early
this afternoon, then enough deeper moisture and lift associated
with the disturbance to arrive NW of NYC for scattered showers.
Instability will be marginal, so mentioned only slight chance of
thunder north and west.
Expect temperatures to be slightly warmer than those of
yesterday, with mid/upper 80s in most place, perhaps touching 90
in NYC and urban NE NJ.
Sea breezes along the coast will be stronger than those of
yesterday as well, reaching 15-20 mph along most of the south
shore of Long Island, and 20-25 mph along the south shores of NYC
and Nassau County. This will promote a high rip current risk at
the ocean beaches this afternoon and early this evening.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Will have 15-30 PoP tonight for isolated-scattered showers and
perhaps some isolated tstms as this first upper level disturbance
moves across during the first half of tonight, then as a slow
moving frontal boundary approaches NW sections late tonight. With
cloud cover and increasing dewpoints expect low temps to be closer
to the high end of guidance, with lower and mid 70s.
The front will drop into the area through the day on Friday, with
once again isolated-scattered showers and possibly a thunderstorm.
Chances for thunder look best across SE CT, and with enough deep
layer shear expect any storms that develop there could produce
High temps ahead of the front will reach 90-95 across a good deal
of the area, which in combination with dewpoints rising to the
lower 70s should yield heat index values at least in the mid 90s.
NYC, urban NE NJ, and the Hudson/CT river valleys could see heat
index values close to 100, and a heat advisory could be needed
for Fri afternoon.
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
NWP guidance is in good agreement across North America at H5 into
Sunday...then differences begin to develop with the progression and
amplitude of a northern stream trough tracking through the upper
Midwest and western Great Lakes in response to downstream ridging.
Meanwhile, a strong mid level anticyclone over the Mid Atlantic
Fri night will remain nearly stationary through the weekend before
weakening and drifting back into the Tennessee Valley early to mid
At the surface, a weak cool front should push south of Long
Island Fri night with a northerly flow and high pressure in its
wake. H85 temps drop to 14-16C by Sat aftn (as opposed to 17-18C
on Fri). Mixing to around this level should yield max temps in the
mid to upper 80s across the area. Flow should also be light enough
during the aftn for seabreeze development at the coast.
The high tracks east of New England on Sunday. Another sunny day
with onshore flow will limit mixing, especially at the coast with
slightly lower max temps. Highs should range from lower to mid
80s...with the exception of urbanized NY/NJ where mid to upper 80s
will be common.
Weak low pressure will track from the Great Lakes Sun morning to
northern New England by Mon morning. The associated warm front lifts
north late Sun/Sun night with a waa pattern ensuing. The heat and
humidity returns on Mon as a cold front slowly approaches from the
northwest. Not much pcpn expected as the majority of the upper
level dynamics passes well to the north and the front runs into
strong subsidence. The front then stalls nearby with perhaps a few
showers Tue and Wed in response to ripples of vort energy and a
few passing jet streaks aloft.
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --High pressure off the Northeast coast slowly moves east through
tonight, giving way to a weak frontal system approaching from the
Ohio Valley. A pre-frontal trough will approach from the west
VFR through the TAF period. There is a low chance of showers
and thunderstorms northwest of New York City during the afternoon
and early evening hours.
S-SW winds gradually increase through this afternoon. Gusts up to
25 KT possible near the coast by late afternoon.
NY Metro Enhanced Aviation Weather Support...
Detailed information, including hourly TAF wind component forecasts,
can be found at: http:/www.weather.gov/zny/n90
KJFK TAF Comments: Possible gusts up to 25 kt this afternoon.
KLGA TAF Comments: No unscheduled amendments are expected.
KEWR TAF Comments: No unscheduled amendments are expected.
The afternoon KEWR haze potential forecast is GREEN...which implies
slant range visibility 7SM or greater outside of cloud.
KTEB TAF Comments: No unscheduled amendments are expected.
KHPN TAF Comments: No unscheduled amendments are expected.
KISP TAF Comments: No unscheduled amendments are expected.
.Outlook for 12Z Friday through Monday...
.Friday...Mainly VFR. MVFR possible in scattered showers/isolated
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Winds on the waters have been running higher than model forecasts.
Expect this trend to continue through tonight, with SW-S flow on
the ocean increasing to 15-20 kt and some gusts 25-30 kt by late
afternoon into tonight, pushing seas up to 5 ft. These winds
should be highest in the NY bight late this afternoon and early
this evening as a coastal jet develops. Have issued SCA for the
ocean waters, for west of Fire Island Inlet beginning late this
afternoon, and then farther east early this evening. Both run
Sub-advy conds generally prevail otherwise. However, potential
remains for long period SE tropical swell on the ocean late this
weekend and early next week. Seas could build to 5-6 ft Sunday
No significant widespread precipitation is expected into next week.
-- Changed Discussion --CT...None.
NY...High Rip Current Risk until 9 PM EDT this evening for NYZ075-
High Rip Current Risk from 4 PM this afternoon to 9 PM EDT
this evening for NYZ080-081.
MARINE...Small Craft Advisory from 4 PM this afternoon to 6 AM EDT
Friday for ANZ355.
Small Craft Advisory from 6 PM this evening to 6 AM EDT Friday
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