000
FXUS61 KOKX 270734
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
334 AM EDT Mon May 27 2019

.SYNOPSIS...
Weak high pressure will build in for today. A warm front
approaching late tonight into Tuesday will briefly stall across
the area as weak low pressure moves along the front. A cold
front moves through Tuesday night. Weak high pressure is then
expected for Wednesday with a surface trough on Thursday, then a
cold front moving through Thursday night into Friday morning.
Weak high pressure then dominates through Saturday morning with
a couple of systems potentially affecting Saturday afternoon
through Sunday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Brief deep layer ridging will build into the region, with
subsidence allowing for mostly sunny skies. Although
temperatures will continue to be above normal, the post-frontal
air mass will be about 5 to 10 degrees cooler than Sunday`s
highs, generally reaching the 70s to lower 80s. Expect sea
breezes to develop along coastal areas later in the day as
northwest flow slackens.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
Warm advection steadily begins to increase into tonight with the
approach of a short wave trough and attendant surface low.
Increasing cloud cover will maintain above normal lows in the
50s across outlying areas, to lower 60s in the more metropolitan
areas.

Thereafter, a first round of showers is expected as a weak
vorticity maximum moves through. A brief lull into the early
evening may occur. There is then significant uncertainty as to
where the warm front will progress during the evening, though
recent deterministic runs have trended slightly farther north,
placing northeastern NJ and potentially portions of NYC and the
lower Hudson Valley into the warm sector. Hi-resolution
scenarios have been hinting at more significant convection
developing on the cold front, which may be enhanced if a decent
amount of clearing can occur in the wake of the initial shower
activity. Flow will be backed in the vicinity of the warm
frontal boundary, and with northwest flow aloft remaining
strong, will lead to SRH values not often seen here, and deep
layer bulk shear values around 50-60 kt. Additionally, mid level
lapse rates should be around 6.0-6.5 C/km. The progression of
the warm front will need to be closely monitored, as there is
certainly potential for supercells in the vicinity of and to the
south of the warm front. Otherwise, a brief period of heavy
rainfall is possible as the cold front moves through, with
everything then quickly clearing after about midnight. Lingering
cloud cover will once again lead to overnight lows that will be
above climatological normals.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Weak high pressure replaces a weak low exiting east on Wednesday.
Models seem to agree that it`s fairly dry above 850mb and with NVA
dominating through most of the day. Shortwave energy and a surface
trough approach late in the day and may be enough to trigger a
shower or thunderstorm mainly over the western half of the Tri-State
area. Chances increase and spread east Wednesday night with these
features moving in along with deepening moisture. The temperature
forecast is a little tricky, but it appears there`s building
convergence towards the warmer side of guidance during this period.

For Thursday the trough exits east in the morning, but thermal
troughing appears to gain strength inland ahead of the next cold
front. Showers/TSTMs possible, but mainly in the afternoon and more
so at night. Still too early to be certain, but potential shear and
CAPE values could aid in strong storms should TSTMs occur.

Timing for the cold front appears to be either late Thursday night
or Friday morning. Will leave in low PoPs Friday morning to cover
this uncertainty, but will then go with a dry weather in the
afternoon. A zonal flow and a weak surface high then probably
maintains dry weather Friday night into Saturday morning. A wave of
low pressure may then form along a stalled boundary to our south and
bring chances of showers and storms Saturday afternoon and night.
The next cold front then brings more chances of showers and storms
on Sunday.

High temperatures from Thursday on are expected to be above
normal.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
High pressure builds today behind a cold front.

VFR forecast through the the TAF period.

Winds have shifted to the NW behind the cold front, with speeds
remaining under 10 kt. Some outlying terminals could go light
and variable early this morning. Winds veer to the N and NE
this morning and then remain northerly into the afternoon around
10 kt. S-SE seabreezes are expected for south coastal terminals
in the afternoon. Winds diminish this 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: Timing of seabreeze may be off an hour or two as
northerly winds shift to the south later in the day.

The afternoon KJFK haze potential forecast is GREEN...which implies
slant range visibility 7SM or greater outside of cloud.

KLGA TAF Comments: At this time, do not expect a southerly seabreeze
to make it to the airport, except possibly in the evening.

The afternoon KLGA haze potential forecast is GREEN...which implies
slant range visibility 7SM or greater outside of cloud.

KEWR TAF Comments: At this time, do not expect a southeasterly
seabreeze to make it to the airport, except possibly in the evening.

The afternoon KEWR haze potential forecast is GREEN...which implies
slant range visibility 7SM or greater outside of cloud.

KTEB TAF Comments: No unscheduled amendments are expected.

KHPN TAF Comments: No unscheduled amendments are expected.

KISP TAF Comments: Timing of seabreeze may be off an hour or two as
northerly winds shift to the south later in the day.

.OUTLOOK FOR 06Z TUESDAY THROUGH FRIDAY...
.Late tonight...VFR.
.Tuesday...MVFR or lower in likely showers. E/SE gusts to 20 kt
possible near the coast.
.Tuesday night...Becoming VFR.
.Wednesday-Thursday night...Chance of MVFR or lower at times in
showers/thunderstorms.
.Friday...VFR.

&&

.MARINE...
With a generally weak pressure gradient, winds and seas will
generally remain tranquil into Friday.

On the ocean, seas may approach 5 ft during Wednesday with a
swell, but likely prevail at 3 or 4 ft. As for winds, they are
expected to increase Thursday into Thursday night ahead of a
cold front, but gusts across all waters should remain below 25
kt.

There may be potential for thunderstorms to pose locally
hazardous conditions at times during the week.

&&

.HYDROLOGY...
Rainfall from late tonight into Tue night should average from
1/2 to 3/4 inch. Up to another half inch may be possible late
day Thu into Fri morning.

&&

.EQUIPMENT...
NYC NOAA Weather Radio Station KWO35 (162.55 MHz) remains off
the air.

&&

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

&&

$$
SYNOPSIS...JC/MD
NEAR TERM...MD
SHORT TERM...MD
LONG TERM...JC
AVIATION...PW
MARINE...JC/MD
HYDROLOGY...JC/MD
EQUIPMENT...

NWS OKX Office Area Forecast Discussion