Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 262022
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
422 PM EDT Fri May 26 2017

.SYNOPSIS...
Low pressure departs the New England Coast tonight as weak high
pressure settles over the region. A weak wave of low pressure
passes to the south Saturday into Saturday night. A series a weak
waves of low pressure or troughs will move through the northeast
Sunday through Thursday. A cold front is expected to move
through the region Friday.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Weak instability and heating within deep cyclonic flow has developed
a few isolated showers this afternoon. Coverage looks to remain
isolated. With loss of heating this evening and now real defined
source for lift, any showers will dissipate.

Heights aloft will continue to rise tonight as low pressure
continues to depart the New England coast. Clouds will dissipate
somewhat, but there is enough low level moisture for at least partly
cloudy skies overnight.

Lows will range from the lower 50s inland to the middle and upper
50s near the coast.

There is a high risk of rip currents into this evening.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Main concern for Saturday is with a convectively induced shortwave
that is currently located over the Upper Mississippi river valley.
Models have not been handling this energy very well as depicted with
Dprog/Dt at H5. However, it appears they are beginning to handle
this feature better with just some timing differences overall. The
shortwave is forecast to quickly traverse through the Ohio Valley
tonight and then towards the region on Saturday. Prefer to follow a
blend of the NAM, 3-km NAM and ECMWF, which brings the shortwave
offshore late afternoon and early evening. The GFS, GEFS, and CMC
are a bit slower and do not bring it offshore until overnight
Saturday. Have elected to go with slight chance PoPs, mainly
for the western half of the area, as better lift and moisture
appears to pass to the south of the region.

Otherwise, mostly cloudy skies are expected with high temperatures
around 70 in NYC and middle and upper 60s elsewhere.

Clouds gradually decrease Saturday night as ridging builds aloft.
Lows will be near normal.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
With a delay in the timing of the northern stream longwave
trough and the shortwave rotating through the base of the trough
have delayed the probabilities of showers until late in the day
Sunday; and mainly across the far west and southwest zones.
Aloft, an upper ridge axis will still be west of the region at
12Z Sunday with heights rising until the afternoon. At the
surface a weak high will be moving off the coast. Then as the
shortwave moves into the region probabilities increase Sunday
night into Monday. At the surface the will be weak forcing as a
weak cold front moves into the region. A thermal ridge also
moves into the area Monday afternoon. Monday may be one of the
warmer days of next week. With weak surface based instability,
and increasing aloft along with increasing CAPE will have
thunderstorms Monday afternoon into the evening. There is still
some uncertainty with the timing of the upper trough and
shortwave for Sunday and Monday.

The closed upper low and longwave trough will be slow to move
east through the week as a series of shortwaves rotate through
the trough, while at the surface weak lows, or troughs move
through the area. There remains a lot of uncertainty with the
timing and placement of the systems through the upcoming week.
And, there will be a prolonged period of unsettled weather. Will
carry slight chance to low chance probabilities through the
week, although there may be periods of dry weather.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
Low pres will track SE of Nova Scotia tonight...and then out to
sea Saturday.

VFR. Isolated showers into early evening with possible brief
MVFR and gusts to 30 kt.

Gusty W/WNW winds to 25 kt into early evening push...diminishing
into tonight. Light NW winds for Sat morning push. S/SE
seabreeze development Sat 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: Winds will waver between 290 and 320
magnetic late this afternoon into eve. Gusts to 25 kt likely
into start of evening push. Isolated shower possible into this
evening with gust to 30kt.

KLGA TAF Comments: Winds will waver between 290 and 320
magnetic late this afternoon into eve. Gusts to 25 kt likely
into start of evening push. Isolated shower possible into this
evening with gust to 30kt.

KEWR TAF Comments: Winds will waver between 290 and 320
magnetic late this afternoon into eve. Gusts to 25 kt likely
into start of evening push. Isolated shower possible into this
evening with gust to 30kt.

KTEB TAF Comments: Winds will waver between 290 and 320
magnetic late this afternoon into eve. Gusts 20 to 25 kt
possible into start of evening push. Isolated shower possible
into this evening with gust to 30kt.

KHPN TAF Comments: W/WNW gusts 20 to 25 kt possible into start
of evening push. Isolated shower possible into this evening with
gust to 30kt.

KISP TAF Comments: W/WNW gusts 20 to 25 kt possible into start
of evening push. Isolated shower possible into this evening with
gust to 30kt.

.OUTLOOK FOR 18Z SATURDAY THROUGH TUESDAY...
.Saturday...MVFR cigs possible. S/SE afternoon sea breeze
expected for coastal terminals...likely into KEWR/KTEB.
.Saturday Night-Sunday...MVFR/IFR. E/SE winds.
.Sunday Night-Monday...MVFR/IFR likely in rain. E winds.
.Tuesday...Improving to VFR. S/SE winds.


&&

.MARINE...
Southerly swell continues on the ocean waters through tonight.
Seas will subside overnight as the swell diminishes. 5 ft seas could
linger east of Moriches inlet through Saturday morning, so have
extended the SCA to account for this. Otherwise, Sub-SCA conditions
are forecast on the waters through Saturday night.

A weak surface pressure gradient force will be across the
forecast waters Sunday through Wednesday as a series of weak
lows or troughs move through the waters with low pressure
remaining north of the Great Lakes into Tuesday night. The lows
then moves slowly east through Friday. Winds and seas will
remain below small craft advisory levels Sunday through
Wednesday.

&&

.HYDROLOGY...
No hydrologic impacts into early next week.

&&

.TIDES/COASTAL FLOODING...
The threat for minor coastal flooding will continue for the
nighttime high tides though Memorial Day Weekend.

Widespread minor coastal flooding is expected for the southern
bays of Western LI and Jamaica Bay tonight...with brief and
localized minor flooding for western Long Island Sound, lower
NY/NJ Harbor, and eastern Great South Bay. Despite high
astronomical tides the offshore flow will be a limiting factor
to surge tonight.

For Saturday Night...although astronomical tides
lower...surge will likely be on the increase. Widespread minor
coastal flooding is expected once again for the southern bays of
NYC/Western LI...and also for coastal Fairfield and Westchester
counties. Brief and localized minor flooding is likely for the
rest of western Long Island Sound, lower NY/NJ Harbor, and
eastern Great South Bay.

Surge likely increases for Sun into Mon...which will continue a
similar threat for coastal flooding despite lower astronomical
tides.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Coastal Flood Advisory from midnight Saturday night to 3 AM
     EDT Sunday for CTZ009.
NY...Coastal Flood Advisory from midnight Saturday night to 3 AM
     EDT Sunday for NYZ071.
     High Rip Current Risk until 9 PM EDT this evening for NYZ075-
     080-081-178-179.
     Coastal Flood Advisory from 8 PM this evening to 1 AM EDT
     Saturday for NYZ178-179.
     Coastal Flood Advisory from 9 PM Saturday to 2 AM EDT Sunday
     for NYZ075-178-179.
NJ...None.
MARINE...Small Craft Advisory for hazardous seas until 6 AM EDT
     Saturday for ANZ353-355.
     Small Craft Advisory for hazardous seas until 11 AM EDT
     Saturday for ANZ350.

&&

$$
SYNOPSIS...DS/MET
NEAR TERM...DS
SHORT TERM...DS
LONG TERM...MET
AVIATION...NV
MARINE...DS/MET
HYDROLOGY...DS/MET
TIDES/COASTAL FLOODING...NV



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