Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 280101
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
901 PM EDT FRI MAY 27 2016

.SYNOPSIS...
Bermuda high pressure will remain across the region through the
weekend. A cold front will pass through the area Monday into
Tuesday. High pressure returns for the middle of the week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Will keep in a chance of thunderstorms inland this evening as
surface based instability remains with CAPE around 1000 J/Kg.
Storms are weakening with loss of best heating of the day. Across
long Island and into southern Connecticut, with a marine layer in
place, there was little to none instability and CAPE. Watching
convection weaken as storms moves through southern Connecticut.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
An evening shower/thunderstorm is possible northwest of the city,
then with the loss of instability and only weak lift, dry
overnight.

For Saturday, still no significant source of lift outside of weak
mid level shortwaves, but SBCAPE will be building once again away
from sea breezes. Again, will go with only slight chance to chance
pops, focused more toward the afternoon and away from areas cooled
by sea breezes.

Highs on Saturday should be warmer than on Friday with warmer temps
at the top of the mixed layer, and probably less cloud cover
overall. Again, needed to adjust a guidance blend upward to account
for the low bias as of late, especially over Long Island.

There is a moderate risk of rip currents at the Atlantic ocean
beaches on Saturday.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Models are in good agreement with the H5 pattern across North
America to start...however timing and amplitude differences start
to become apparent by the middle of the week and even more so by
weeks end.

Sub-tropical ridge over the western atlantic begins to
break down and shift e during the latter part of the weekend but
should still have enough of an influence on the area to keep any
convection associated with an approaching back door cold front
mainly to the north...although it may be close enough for some
storms across the interior...so have maintained the low chc pops
there.

Moisture from a tropical disturbance off the Carolina coast is
forecast to feed up the east coast along a pre-frontal trough
Sunday night and Monday as a cold front approaches from the west.
There is the potential for heavy rainfall with this system as a
plume of tropical moisture surges northward ahead of the
aforementioned system near the SE coast. These values are close
to the maximum observed precipitable water for May 30 per SPC
Sounding Climatology. An approaching shortwave in the northern
branch and sfc cold front will shift this activity to the east
Monday night.

Deep layered ridging then returns through the rest of the week
with the return to summer-like temperatures.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
The area will remain on the western side of the Bermuda High into
Saturday with a thermal trough across then interior each
afternoon.

Convection has largely dissipated across the area. Additional
activity moving into NE PA is likely to dissipate before reaching
the Lower Hudson Valley later this evening.

The main feature of focus this evening is the low-level coastal
jet still impacting KJFK with gusts up to 25 kt. This feature
typically weakens gradually in the evening while spreading east.
KISP may see a brief period of gusts to around 20 kt.

With a more humid air mass in place than last night, radiational
cooling via diminishing S-SW winds under mostly clear skies
should promote development of mist with MVFR vsby late tonight
into the early daylight hours outside of the NYC metro terminals,
and possibly KJFK. A brief period of IFR vsby not out of the
question at KGON/KHPN/KISP.

On Saturday, S-SW winds will strengthen to 10-15 kt by afternoon.
A southerly coastal low level jet should once again develop and
impact KJFK and KLGA late. There is also chance of a late day
tstm near KSWF.

...NY Metro Enhanced Aviation Weather Support...

Detailed information...including hourly TAF wind component fcsts
can be found at: http:/www.weather.gov/zny/n90

KJFK TAF Comments: Brief period of MVFR vsby not totally out of
the question late tonight into the early daylight hours.

KLGA TAF Comments: No unscheduled AMD expected.

KEWR TAF Comments: Brief period of MVFR vsby not totally out of
the question late tonight into the early daylight hours.

KTEB TAF Comments: No unscheduled AMD expected.

KHPN TAF Comments: No unscheduled AMD expected.

KISP TAF Comments: Occasional gusts up to 20 kt possible early
this evening.

.OUTLOOK FOR 00Z Sunday through Wednesday...
.Saturday night-Sunday...Mainly VFR with afternoon sea breezes.
Chance of MVFR or lower in any isolated to scattered afternoon and
evening showers/thunderstorms mainly near KSWF.
.Sunday night-Monday...Showers likely and chance of tstms, with
MVFR of lower conditions expected.
.Monday night-Tuesday...Becoming VFR. Coastal sea breezes in
the afternoon.

&&

.MARINE...
With the Ambrose jet in place, with gusts at KJFK near 30 kt,
winds and seas were approaching small craft levels at buoy 44065.
Conditions should be brief and subsiding as the evening
progresses. Elsewhere across the forecast waters winds and seas
remain below small craft levels.

The western periphery of Bermuda high pressure remains across the
waters through Saturday. Winds and seas are expected to remain
below small craft levels during this period.

A weak pressure gradient across the waters will then keep winds
and seas below sca levels through Tuesday.

&&

.HYDROLOGY...
Isolated to scattered thunderstorms are possible mostly for the
inland areas this evening, and Saturday afternoon. However, no
significant widespread precipitation is expected through the
weekend.

Rainfall amounts around one half to three quarters of an inch are
possible on Monday with locally higher amounts. Localized urban or
poor drainage flooding is possible from the heaviest rain.

&&

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

&&

$$


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