Area Forecast Discussion
Issued by NWS Upton, NY
FXUS61 KOKX 301748
Area Forecast Discussion
National Weather Service New York NY
148 PM EDT Fri Sep 30 2016
The region will remain in between high pressure to the northeast
and low pressure to the southwest through the weekend. The low
then slowly exits to the east through Tuesday as high pressure
builds into the north. This high then continues to build down
into the region through the middle of next week.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Looking at latest radar trends and 12z GFS appears to be having a
fairly decent handle on current precipitation. Based on these have
lowered pops, especially over western zone, and also gone over to
areal coverage wording for chance pops or lower and intermittent
for categorical pops. Based on this, have also lowered pops
slightly this afternoon a well. Refer to the hydrology section of
the AFD for details.
Generally a cool, damp afternoon with gusty NE winds, up to 35-40
mph near the coast. Highs should mainly be in the upper 50s-lower
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
Based on latest radar trends and 12z guidance, did lower pops and
qpf this evening over mainly western zones. Remainder of forecast
for tonight and Saturday was left unchanged.
Chances for rain continue into the short term with the cut off
low remaining to the west and the frontal boundary to our south.
Again, models differ on exact placement of the heaviest rain.
Refer to the hydrology section of the AFD for details.
Winds diminish tonight as the pressure gradient relaxes somewhat
over the region. Temperatures will be a bit warmer on Saturday,
but still a bit below normal for this time of year, generally
lower to middle 60s.
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
No significant changes made to the long term period as a stagnant
and unsettled weather pattern continues for the weekend and into
early next week as a stacked cutoff low remains over the Ohio
Valley as a ridge over the Western Atlantic remains in place. Models
continue to show the upper ridge gradually weakening and shifting
south enough early next week to allow the upper low to finally start
moving northeast early next week.
At the surface, stacked low pressure sits over the Ohio
Valley, with a stationary front running northeast from the Mid
Atlantic and southeast of Long Island through the weekend. A
series of weak waves running along this front will produce periods
of rain this weekend. Then as the stacked low finally begins to
lift northeast early next week, expect the the main moisture/lift
axis to also weaken and lift NE. Lingering scattered showers could
continue through early next week via cold pool instability
interacting with the maritime air mass.
Thereafter, potential for deep layered ridging developing for mid
week as the region lies under ridging of an omega blocked pattern.
The dry ridged pattern may continue into late week, but will have
to monitor the evolution of Hurricane Matthew. Please refer to
the National Hurricane Center forecasts for further information.
Temperatures will be at or slightly below normal on Sunday,
then return to near seasonable for early next week.
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
The terminals will remain between high pressure to the northeast
and low pressure to the southwest through the weekend.
Mainly MVFR conditions this afternoon and evening. Pockets of IFR
visibilities are possible in -SHRA through this evening. Ceilings
likely fall to IFR late this evening and overnight with a
lower chance of -SHRA. Flight categories then improve to MVFR
after 12z Saturday as -SHRA redeveloping.
NE winds through the TAF period. Gusts 25-30 KT at city/coastal
terminals and 20-25 KT at inland terminals. Strongest gusts
expected through this evening before diminishing overnight.
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: IFR visibilities possible at times in -SHRA.
Gusts to 30 kt possible. Low chance for IFR ceilings after 22z.
KLGA TAF Comments: Brief IFR ceilings through 19z. IFR
visibilities possible at times in -SHRA. Gusts to 30 kt possible.
KEWR TAF Comments: IFR visibilities possible at times in -SHRA.
KTEB TAF Comments: Amendments for flight categories possible. Gusts
may be more occasional than indicated.
KHPN TAF Comments: Amendments for flight categories possible. Gusts
may be more occasional than indicated.
KISP TAF Comments: IFR visibilities possible at times in -SHRA.
Gusts to 30 kt possible.
.Outlook for 18Z Saturday through Wednesday...
.Saturday afternoon...IFR/MVFR in rain.
.Saturday Night-Sunday Night...MVFR or lower possible with showers.
.Monday-Tuesday...Mainly VFR with isolated to scattered showers
.Wednesday...VFR. NE gusts 20-25 kt near the coast.
Minor changes were made with this update to reflect the latest
trends in observations and guidance. The forecast appears on
Gusts to gale force are expected into this evening on all but NY
Harbor, where Small Craft Conditions are expected through tonight. SCA
winds are also expected on the remainder of the waters through at
least 10z Saturday as well. The strong winds will drive high seas,
with seas ranging from 8-13 ft on the coastal ocean waters and
from 5-7 ft on the Sound.
SCA criteria should continue into mid Saturday morning for the
ocean waters, while everywhere else, winds will come down below 25
kt around sun rise. Waves over the Sound will also come down below
5 ft by around sun rise on Saturday. Waves will diminish on the
ocean waters as well, but they will remain at or above 5 ft
through the day Saturday.
Conditions fall below SCA levels Sat night into early Sunday as
easterly flow weakens and seas subside. These sub-SCA conditions
will remain likely for early next week under a weak pressure
Seas on the ocean waters start to increase mid week with small craft
There is a high degree of uncertainty on the amount of rainfall
through Saturday. Around 1-1 1/2 inches of QPF possible through
Saturday night, with locally higher amounts possible. The
prolonged nature of the rain event should preclude any hydrologic
No significant rainfall for early to middle portion of next week.
Although wind fields weaken by the high tide this evening,
widespread minor flooding continues to be a concern for the south
shore of Long Island and thus a Coastal Flood Advisory remains in
effect for this time frame for Southern Nassau County.
Additionally, a persistent easterly sweep of 6 to 10 ft surf
today will likely result in minor to moderate beach erosion
issues at the the ocean beachfront.
NY...Coastal Flood Advisory from 6 PM to 10 PM EDT this evening for
MARINE...Small Craft Advisory until 8 AM EDT Saturday for ANZ338.
Gale Warning until 8 PM EDT this evening for ANZ330-335-340-