Area Forecast Discussion
Issued by NWS Upton, NY-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KOKX 182251
Area Forecast Discussion
National Weather Service New York NY
551 PM EST Sat Feb 18 2017
Low pressure tracks along southern Canada, and into northern
New England tonight, and then into the Canadian Maritimes
Sunday into Sunday night. A cold front with the low passes
through the region late tonight into Sunday morning. High
pressure builds in behind the low Sunday night. A warm front
will approach Tuesday night followed by a weak cold front
becoming nearly stationary in our vicinity Wednesday through
Friday. A separate cold front approaches from the west Friday
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
-- Changed Discussion --Only minor adjustments needed as temperatures are still higher
than originally forecast. Well above normal temperatures
expected to continue through the night. Previous discussion
below remains valid.
An upper low and associated surface low track through
southern Canada tonight with an upper shortwave and vort max
rotating north of the region. A cold front with the low will
move into the northern portions of the CWA after 06Z. Weak cold
advection sets up 03Z to 06Z. With much of the energy remaining
to the north, and with limited moisture and lift across the
area, the cold front is expected to move through dry; there may
be a few sprinkles in the Lower Hudson Valley hills.
Increasing cloudiness and winds not expected to decouple will
keep temperatures from falling off rapidly, especially in the
normally colder locations.
-- End Changed Discussion --
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
The cold front moves through early Sunday morning. This will be
more of a dew point front as temperatures across much of the
area will be near or higher than Saturday`s highs. Cold
advection will be weak however mixing will be deeper, up to 900
MB compared to 950 MB Saturday.
The upper low will remain across eastern Canada Sunday night
with another shortwave and vort max rotating through the upper
low. Again much of the energy and lift will remain well north of
the CWA. The surface low will be well to the east and another
cold front will approach by late Sunday night.
.LONG TERM /MONDAY THROUGH SATURDAY/...
A brief cooler period is expected Monday and Tuesday amidst
cold air advection as an area of high pressure quickly moves
through. Temperatures will be within a few degrees of
climatological normals during this time frame. Mid and high
level cloud cover will begin to increase Tuesday ahead of an
approaching area of low pressure. Warm advection and cloud
cover will keep temperatures mild Tuesday night. Light
precipitation will begin after midnight, with a chance of light
freezing rain across northern Connecticut Wednesday morning
before temperatures rise above freezing after sunrise. Light
rain accumulations are expected elsewhere. Despite the surface
trough moving through, flow will remain southwest ahead of a
separate slowly approaching trough. Temperatures are expected
to be well above normal through the remainder of the week, with
increasing chances of rain by late week as the trough moves
closer to the region.
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
VFR conditions through the TAF period. Low pressure moves well
north of the terminals, sending cold front through Sunday
S-SW winds 10-13 kt through this afternoon. A gust 18-20 kt
remains possible for the next few hours, but will not be
frequent. A low level jet around 2 kft develops this evening
with LLWS expected east of the city terminals.
Tonight, winds veer to the SW under 10 kt at city terminals and
light and variable elsewhere. Winds continue to veer Sunday to
the WNW, possibly averaging near 310 magnetic late morning into
.OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY...
.Monday...VFR. NNW gusts near 20kt.
.Monday night-Tuesday evening...VFR.
.Tuesday night-Wednesday...MVFR possible in rain.
-- Changed Discussion --Made minor adjustments this evening to increase seas by 1 ft on
ocean waters per recent buoy observations. Winds and seas will
remain below small craft advisory levels tonight and Sunday as a
low pressure system moves through southern Canada and into
northern New England. A cold front with the low will pass
through the waters late tonight into early Sunday morning.
Southwest winds ahead of the cold front will build seas on the
ocean waters and across portions of the waters east of Moriches
Inlet seas may briefly reach 5 feet before the cold frontal
passage. Then in the northwest flow behind the front, gusts on
the ocean waters by late Sunday night may be near 25 KT. No
precipitation is expected with the frontal passage.
Following the cold frontal passage and as canadian high
pressure builds southeast across the area, a Small Craft
Advisory/SCA is possible across the Atlantic Ocean coastal
waters south of Long Island Sunday night and Monday as NW winds
range from 15-20 kt with occasional gusts near 25 kt and seas
build to around 4 feet. The next potential chance of marine
impacts will be late in the week on Friday/Saturday as winds
strengthen ahead of an approaching low pressure system.
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No hydrologic impacts are anticipated through the next 7 days.