-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 212347
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
747 PM EDT Thu Jun 21 2018

.SYNOPSIS...
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Cold front over New England will dissipate over the region this
evening with high pressure to build north of the area. The high
lifts to the north and east on Friday as a frontal system
approaches from the southwest. A warm front passes late Saturday
into Saturday night and will be followed by cold fronts on
Sunday and then on Monday. High pressure returns for Tuesday and
Wednesday.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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A cold front passing through New England this evening will
dissipate as it moves across the area. A few showers, mainly
across southeast Connecticut through early this evening. This is
a real low chance and will be widely scattered should any
develop.

Weak cold advection and the upper trough passing through the
northeast will allow high pressure to build to the north of the
area tonight. This will allow a light S/SE flow to back to the
NE.

Stratus/patchy fog deck along E LI/SE CT will continue to drift
westward across much of E LI/SE CT through midnight in easterly
flow ahead of weak cold front. Expectation is this should begin
to get suppressed offshore late tonight into Fri morning as flow
becomes ne and drier air advects south as cold front
dissipates.

Overnight lows will be nearly seasonable ranging from the upper
50s across the interior, to the mid and upper 60s across the
NYC metro.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Upper trough lifts out across the Northeast on Friday, while
heights build ahead of an upper low lifting northeast into the
Ohio Valley. This will send a warm front northward along the
Mid Atlantic coast as high pressure centered over Northern New
England moves out into the western Atlantic.

Overrunning mid and upper level clouds will increase through
the day with a strengthening easterly flow between the departing
high and associated warm front to the south. Gusts up to 20 mph
will be possible, especially near the coast.

Additionally, a frontal wave along the warm front passes off to
the south and east of the area Friday night. This in turn may
strengthen the low-level ridging across the area enough to
maintain dry air. There have been multiple scenarios playing
out in the guidance the last several days with the potential for
rainfall Friday night, but latest indications are that the rain
will arrive late and should be mainly light. Also, the upper
low is weakening and opening up as it runs into the ridge over
the western Atlantic. Should the frontal wave be a little father
west than forecast, this would pose the potential for steadier
rain across eastern Long Island. There is low confidence in this
scenario.

More or less this will be an easterly flow event with some
light rain and cooler temperatures. Highs on Friday will be in
the 70s, with lows in the upper 50s to lower 60s.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Upper low will continue to open up and flatten through the day on
Saturday as it moves across the Great Lakes region. The flattening
shortwave will continue to traverse across New England on Sunday.
The main upper flow over the Northeast this weekend into next week

Closed upper low opens as it traverses across the Great Lakes region
and into New England this weekend. Another shortwave in a broader
cyclonic flow regime aloft will pass on Monday. Upper ridging
returns for Tuesday into Wednesday with the next possible shortwave
for next Thursday.

There has not been too much change in the overall thinking for
sensible weather. There are still differences in the model guidance
with the depth of surface ridging and the exact direction of the
surface winds. The NAM on Saturday has northeast flow at the surface
and the GFS is more easterly.  The NAM depicts a weak surface wave
moving off the south and east on Saturday and the GFS has less of a
reflection of a surface wave. This will make a big difference in low
level moisture and the potential advection of drier dew points from
the northeast into the region. Confidence in higher PoPs has lowered
and therefore have lowered them until the evening hours. Saturday
may just remain overcast with some light rain at times, with better
forcing and moisture arriving in the evening as the warm front and
shortwave axis nears the region. The shortwave axis lifts up into
northern New England after 06z, which will end any showers.
Instability is weak Saturday night, so will just mention slight
chance of thunder.

Westerly flow aloft will dry the middle and upper levels out enough
for a return to partly cloudy condition on Sunday. A trailing cold
front approaches late in the day along with some trailing shortwave
energy. A chance for showers and thunderstorms is supported by these
systems in the afternoon and evening. A much sharper upper level
trough approaches late Sunday night into Monday with a secondary
cold front ahead of it. The GFS is much stronger with the embedded
energy within the trough which agrees with the CMC. The ECMWF is
much broader and faster with the trough. Low PoPs will persist into
Monday for a continued chance of showers.

High pressure returns for Tuesday into Wednesday with the next cold
front approaching on Thursday. Temperatures should then average near
normal for next week.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
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A weak cold front moves south of the terminals early this
evening, and then dissipates tonight. High pressure begins to
slowly build in from the north tonight and moves off the
northeast coast Friday.

Meanwhile another frontal boundary will remain well to the
south, through the mid Atlantic region and off the coast. A wave
of low pressure will approach from the west late in the
forecast period.

VFR conditions remain through Friday evening. However, with a
northeast to easterly flow, there is some potential for stratus
to move into the region, with the possibility of MVFR ceilings
at KISP. Stratus has already moved into KGON and conditions
there are expected to remain LIFR overnight, then improve early
Friday morning.

Sea breezes weaken early this evening with winds shifting back
to NE to E under 10 KT. Winds may be light and variable for a
brief time before becoming NE to E. Winds will then increase
from the east to southeast, 10-15, Friday morning, and then
remain into the . r afternoon. Occasional gusts to near 20 KT
are possible during Friday 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: No unscheduled amendments expected through Friday.

KLGA TAF Comments: No unscheduled amendments expected through Friday.

KEWR TAF Comments: No unscheduled amendments expected through Friday.

KTEB TAF Comments: No unscheduled amendments expected through Friday.

KHPN TAF Comments: No unscheduled amendments expected through Friday.

KISP TAF Comments: Amendments are possible overnight and early
Friday morning with the potential for MVFR ceilings.

.OUTLOOK FOR 00Z SATURDAY THROUGH TUESDAY...
.Friday night...VFR early, then becoming MVFR with a chance of
light rain.
.Saturday...Sub-VFR. Showers likely, possibly a thunderstorm
during the evening and nighttime hours.
.Sunday...Chance of sub-VFR conditions in showers and
thunderstorms.
.Monday...Chance of showers early, becoming VFR.
.Tuesday...VFR.
-- End Changed Discussion --

&&

.MARINE...
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Dense fog advisory has been issued for ocean and eastern
nearshore waters tonight as stratus/fog deck advects into the
waters. This stratus deck should eventually get suppressed
south mainly over the ocean late tonight into Friday morning.

A strengthening easterly flow late tonight into Friday will
result in building seas and the potential for marginal SCA
conditions on the ocean waters Friday into Friday night.
Preference at this times was to hold off on any issuance.

Winds will likely stay below 25 kt Saturday through early next
week. Winds on the ocean may approach 20 kt at times this
weekend, but will otherwise stay below 25 kt through early next
week.

Ocean seas may build to 5 ft this weekend as a warm front moves
north and SW flow increases. Ocean seas may also approach 5 ft on
Monday with seas otherwise remaining below SCA levels on Tuesday.
-- End Changed Discussion --

&&

.HYDROLOGY...
Some light rain is possible Friday night into Saturday.

There could be a few locally heavy downpours on Saturday night
and Sunday, but no hydrologic impacts are anticipated this
weekend.

&&

.EQUIPMENT...
NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) remains off
the air for an extended period of time.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...None.
NY...None.
NJ...None.
MARINE...Dense Fog Advisory until 8 AM EDT Friday for ANZ330-340-345-
     350-353-355.
-- End Changed Discussion --

&&

$$
SYNOPSIS...DS/DW
NEAR TERM...NV/DW
SHORT TERM...DW
LONG TERM...DS
AVIATION...19
MARINE...DS/NV/DW
HYDROLOGY...DS/DW
EQUIPMENT...