Area Forecast Discussion
Issued by NWS Upton, NY-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KOKX 232151
Area Forecast Discussion
National Weather Service New York NY
551 PM EDT TUE AUG 23 2016
High pressure over the region will slide offshore through
Thursday. A cold front will slowly approach from late Thursday
into Friday, and move across Friday evening. High pressure will
follow for the weekend. Another frontal system will approach on
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
High pressure will remain overhead through Wednesday morning. This
will result in clear skies overnight, although continued southerly
flow will allow dewpoints to slowly increase, resulting in less
than ideal conditions for radiational cooling and overnight lows
that are 5-10 degrees warmer than last night.
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
-- Changed Discussion --High pressure begins to slowly shift offshore during the day on
Wednesday. This will allow for increased southerly flow along with
slightly higher temperatures and dewpoints. High clouds will then
begin to increase overnight Wednesday night as the ridge flattens
ahead of an approaching cold front.
There is a moderate risk for meteorological enhancement of rip
current formation at Atlantic Beaches on Wednesday.
-- End Changed Discussion --
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Operational and ensemble models are in good agreement for the long
term, especially with the passage of the cold front on Friday.
In the mid and upper levels, a weak upper level trough moves through
on Thursday. This trough looks stronger to the north of the area. At
the surface, high pressure will be situated off the East Coast. This
will pump in a warm and humid air mass, out ahead of an approaching
cold front. Surface low pressure over southeastern Canada will trek
east-northeast with its associated cold front approaching the area
Thursday night. A pre-frontal surface trough should impact the area
late Thursday night, mainly for areas north and west of New York
City. Any precipitation should hold off until this trough moves over
the area. So will push back slight chance POPs late Thursday time
Upper level flow looks to be rather zonal Thursday night into
Friday, so would expect the cold front to be rather progressive,
moving through late in the day Friday/early Friday night. However,
not much in the way of moisture for this front to tap into, so much
of the area could remain dry as the cold front moves through. some
surface based CAPE will allow an isolated thunderstorm to develop.
High pressure builds in behind the front for the weekend. Upper
level ridging for late Saturday into Sunday, with another surface
cold front approaching Sunday night. There is some uncertainty with
the passage of this cold front. 12Z GFS is more progressive than the
00Z ECMWF and pushes the front through late Monday night with high
pressure building in for Tuesday. The ECMWF stalls the front just to
our south, with disturbances tracking along the boundary.
As far as temperatures are concerned, seasonably warm for Thursday
with temperatures in the lower to middle 80s, warmer for Friday
under warm advection, with lower 90s possible in the New York City
metro area. Not as warm for Saturday, but still above normal for
this time of year. Thereafter, slightly cooler, but still above
normal temperatures for the rest of the long term.
Humidity levels will increase Thursday into Thursday night, with dew
points in the lower 70s by Friday. Heat index values could approach
the middle to upper 90s for the metro area on Friday, but this will
only be for one day as the cold front ushers in a cooler and
slightly less humid air mass for the remainder of the long term.
Heat index of 100 in the metro area looks unlikely at this time.
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
-- Changed Discussion --High pressure slowly slides offshore into Wednesday.
VFR through the TAF period.
Seabreeze through CT terminals and KJFK/KISP. No looks like
unlikely to move into KLGA/KHPN and will not move into KEWR/KTEB.
Have removed seabreeze from TAF at all 4 locations. Winds become
light and variable throughout this evening, with seabreezes
impacting all terminals but KSWF late Wednesday morning/early
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: Gusts to 15-20kt likely trough 00z, with
isolated gusts possibly lingering to 01-02z.
KLGA TAF Comments: Very low chance of seabreeze passage through
KEWR TAF Comments: Isolated gusts to 15-20kt possible through 00z.
Wind direction could vary from 250 true/260 magnetic to 290T/300M
until become light and variable.
KTEB TAF Comments: No unscheduled amendments are expected.
KHPN TAF Comments: No unscheduled amendments are expected.
KISP TAF Comments: Isolated gusts to 15-20kt possible through 00z.
.Outlook for 18Z Wednesday through Sunday...
.Wednesday-Wednesday night...VFR. Afternoon seabreezes expected.
.Thursday-Thursday night...Mainly VFR. Slight chance of
afternoon/nighttime showers and thunderstorms, with brief MVFR
conditions possible. Best chances North and West of NYC.
.Friday...Mainly VFR. Slight chance of afternoon showers and
thunderstorms, with brief MVFR conditions possible.
-- End Changed Discussion --
Winds and seas should remain below SCA criteria into early next
week. There is still a small to medium chance that ocean seas and
wind gusts could reach SCA criteria some time Thu night into Fri
ahead of a cold frontal passage. There is also a suggestion of
tropical swell encroaching on the waters by Sunday, with waves
building to 5+ ft late in the long term period.
No significant widespread precipitation is expected through