Area Forecast Discussion
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FXUS61 KOKX 291515 CCA
Area Forecast Discussion...CORRECTED
National Weather Service New York NY
1115 AM EDT WED JUN 29 2016
A cold front will move slowly slides east across the Tri-State
into tonight, followed by weak high pressure building in through
Thursday, then weakening over the region into Friday. A cold
front moves over the Tri-State from Friday night into Saturday
morning. High pressure builds in behind the front and prevails
through early next week.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A 700-500 hPa trough will push into the area this afternoon, as
its core lifts to the northeast into eastern Quebec. 12z KOKX and
KALY soundings show a basically dry atmosphere above around 650
hPa, with a cap around the same level. These two limiting factors
should keep most, if not all the area dry this afternoon. However,
cannot completely rule out a stray shower/thunderstorm due to
dynamical forcing from the aforementioned trough. Have confined
the mention of such in the grids/forecast mainly to SE CT, as this
is the area experiencing the best dynamics, and having the most
unstable airmass (CAPES 600-750 J/kg). Note: the HRRR is over
doing the extent of convection currently, and so is not being
trusted in its current run for convective coverage/placement.
Highs this afternoon will be near normal in the immediate NYC
Metro and run up to around 5 degrees above normal elsewhere,
consistent with a blend of MAV/MET/ECS/LAV guidance and NAM and
HRRR 2-meter temperatures.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
Dry conditions should persist through Thursday with high pressure
continuing to build in. Temperatures will continue to be
seasonable, with humidity levels continuing to drop into Thursday.
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Upper low south of Hudson Bay will rotate through the mean trough
and pass through eastern Canada and the Northeast by the close of
the weekend. The latter of which will send a cold front across
the area late Friday night into Saturday morning, preceded by a
round of showers and thunderstorms Friday afternoon and evening
along and ahead of a pre-frontal trough. There is the potential
for some organization with moderate deep-layer shear and CAPES
over 1000 J/KG across much of the area. In addition, models are
pointing toward showers developing overnight Thursday as moisture
returns around the western periphery of offshore high pressure,
interacting with mid level short wave energy. The forecast is
slowly trending in this direction. High pressure follows for the
weekend into early next week. The 00Z GFS bring a southern branch
system close enough to the area Tuesday for showers, however, the
ECMWF is suppressed to the south. Subsequent model trends will
need to be watched, but for the time will keep the forecast dry.
Temperatures continue to remain near seasonable levels throughout
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
A cold front will move slowly east across the local area today
followed by high pressure tonight and Thursday.
Mostly VFR today, but tempo cigs 2000-3000ft this morning.
NW-W winds at 10 kt or less outside of sea breezes.
Cannot rule out an isolated TSTM mainly E of NYC near the cold
front and possibly along developing sea breeze fronts.
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: Amendments possible for timing the development
of sea breezes. Timing within 2 hours.
KLGA TAF Comments: Amendments possible for timing the movement of
the sea breeze toward KLGA.
KEWR TAF Comments: Amendments possible for timing the movement of
the sea breeze toward KEWR.
The afternoon KEWR haze potential forecast is GREEN...which implies
slant range visibility 7SM or greater outside of cloud.
KTEB TAF Comments: Amendments not expected.
KHPN TAF Comments: Amendments not expected.
KISP TAF Comments: Amendments possible for timing the movement of
sea breezes within 2 hours. Isolated TSTM possible aft 16z.
.OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...
.Thursday through Friday morning...VFR.
.Friday afternoon and night...MVFR or IFR conditions possible in
.Saturday and Sunday...VFR.
Made minor changes this update to reflect the latest trends in
observations and guidance.
A relaxed pressure gradient over the waters will keep winds to 10
kt or less through Thursday. A lack of any significant swell will
keep seas to 3 ft or less and waves to 1 ft or less over the
waters around Long Island through this period as well.
Winds and seas are forecast to remain below small craft advisory
levels from Thursday night through the holiday weekend.
No significant rainfall is expected through Friday morning.
Scattered showers and thunderstorms are possible Friday afternoon
into early Saturday. Antecedent conditions are very dry, so
widespread hydrology issues are not expected.