Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 281555
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1155 AM EDT TUE JUN 28 2016

.SYNOPSIS...
A cold front will approach from the west this afternoon and
evening, then slowly move across the Tri-State through Wednesday.
Weak high pressure returns for Thursday through Friday. Another
cold front then approaches and passes through late Friday night
into Saturday. High pressure builds in behind the front Sunday and
Monday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A short wave trough will be moving SE toward the area along with
its surface cold front reflection this afternoon.

Showers lingering a tad longer over far E Long Island than
originally forecast, so have upped pops there. Also, noting
extensive cloud cover over the area, have slowed down timing of
onset of thunder across the area, as any instability will be slow
to be achieved.

Latest high resolution models suggest that any significant CAPE
(1000 J/kg or more) will be confined to areas mainly W of the
Hudson River this afternoon. Also looking at latest regional radar
and HRRR suggest that most areas could remain dry through around
21z, so have reduced pops through this afternoon as well. In
addition, have now confined any mention of small hail, gusty winds
and heavy rain to far Western Orange county at 21z, consistent
with this.


In any case, there is a Slight Risk or severe TSTMs mainly for
Orange County and a Marginal Risk further east across NYC and SW
CT...mainly aft 20z with damaging winds being the primary threat.
The marginal risk area likely is over done, given current
expectation for significant CAPE to be focused mainly W of the
Hudson River.

An Outlook was issued for these potential hazards and impacts.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
The short wave trough is forecast to gradually move east with the
trough axis nearly overhead by 6 pm Wednesday.

Any potential severe TSTMs Tuesday evening should end by midnight
with showers ending by 10z Wednesday.

SCT instability TSTMs are possible aft 16z Wednesday with the
approach of the short wave trough axis.

Temperatures are forecast near normal through the period.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
As has been the case for the last several weeks, still no hot
weather on tap for the region with minor fluctuations around the
mean. The mean upper trough will continue to reside across eastern
Canada, the Great Lakes, and Northeast, while an amplified upper
ridge over the western U.S. gradually flattens into early next
week. At the same time, an upper low near Hudson Bay translates
east.

At the surface, weak high pressure over the Midwest builds into the
area Thursday and then offshore Thursday night ahead of an
approaching cold front and pre-frontal trough. The latter of which
is associated with the upper low/trough working across eastern
Canada. There is a chance of showers and thunderstorms Friday into
Friday night with the best chance being across the interior where
the greatest instability will exist. Deep-layer shear increases with
the approaching upper trough. Dry air could be a limiting factor for
any organization. Cold front works east of the area Saturday morning
with high pressure to follow through early next week.

&&

.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
A cold front approaches later today and passes through the region
late tonight through Wednesday morning.

S/SE winds around 10KT.

Cigs at city and western terminals 700-1200 ft through early
afternoon, possibly lifting later this afternoon before a chance
of showers and tstms late in the day/early evening.

     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 cigs could prevail all afternoon. Late
day/early evening shra/tstm timing could be off by an hour or
two...forecast is more likely to be too early with rainfall.

KLGA TAF Comments: IFR cigs could prevail all afternoon. Late
day/early evening shra/tstm timing could be off by an hour or
two...forecast is more likely to be too early with rainfall.

KEWR TAF Comments: IFR cigs could prevail all afternoon. Late
day/early evening shra/tstm timing could be off by an hour or
two...forecast is more likely to be too early with rainfall.

The afternoon KEWR haze potential forecast is YELLOW...which implies
slant range visibility 4-6SM outside of cloud.

KTEB TAF Comments: IFR cigs could prevail all afternoon. Late
day/early evening shra/tstm timing could be off by an hour or
two...forecast is more likely to be too early with rainfall.

KHPN TAF Comments: IFR cigs could prevail all afternoon.

KISP TAF Comments: Cigs 1000-1500 could prevail most of the
afternoon.

.OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...

.Wednesday morning...MVFR and IFR/lower (coastal terminals)
conditions possible via morning fog/low clouds and rain.

.Wednesday afternoon through Friday morning...VFR.

.Friday night...MVFR or IFR conditions possible in showers/tstms.

.Saturday...Mainly VFR.

&&

.MARINE...
Made minor changes this update to reflect the latest trends in
observations and guidance. The main change was to slow down the
timing and extent of thunder of the waters this afternoon/early
this evening.

Winds and seas are forecast to generally remain below Small Craft
Advisory/SCA levels of 25 kt and 5 feet across the Atlantic Ocean
coastal waters through the period.

Cold frontal passages with wind shifts are forecast late
Wednesday and Friday night.

&&

.HYDROLOGY...
This Afternoon through Tonight: 1/4 to 2/3 of an inch of rain is
forecast, with locally higher amounts possible in stronger
convection. Based on high surface dew points and precipitable
water contents, can not rule out isolated flash flooding of low
lying and poor drainage areas in areas experiencing locally heavy
rainfall.

Friday Afternoon and Evening: Scattered showers and thunderstorms
may produce localized heavy rainfall, mainly north and west of
NYC.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.

&&

$$
SYNOPSIS...GC/DW
NEAR TERM...GC/Maloit
SHORT TERM...GC
LONG TERM...DW
AVIATION...JC/MPS
MARINE...GC/Maloit/DW
HYDROLOGY...GC/DW


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