560
FXUS61 KOKX 181938
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
338 PM EDT Sat May 18 2024
.SYNOPSIS...
-- Changed Discussion --
A couple of upper troughs will be in the vicinity through
tonight, otherwise surface high pressure will be in place
through Monday. The high gradually slides farther out into the
Atlantic through midweek. A frontal system approaches from the
west Wednesday night. The associated cold front approaches
Thursday and moves across Thursday night. Brief weak high
pressure returns towards the end of the week.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
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High pressure will slowly build into the region from the northeast
tonight. At the same time, a couple of shortwaves will be nearby,
triggering some showers for parts of the forecast area, primarily
into the evening hours. After midnight, looks like any chance of
additional showers will be east of the city with a mid-level
shortwave still nearby. Low temperatures a few degrees above normal
with plenty of cloud cover around.-- End Changed Discussion --
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
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Surface high pressure along the new England coast remains in control
during this time. A lingering shower still possible for eastern
zones in the morning, and although another shortwave may arrive here
during the afternoon, moisture will be more shallow. Will therefore
go with a dry forecast for the afternoon. Partly to mostly cloudy
conditions in the morning, then probably at little less in the way
of clouds during the afternoon. Highs near normal in the upper 60s
to lower 70s. Heights rise aloft Sunday night into Monday. It could
start out mostly cloudy in the morning for coastal areas, but
anticipating mostly sunny conditions across the entire area during
the afternoon. Based on mixing up to around 925mb, deterministic NBM
looked reasonable for high temperatures. Highs ranging from near 80
for parts of the Lower Hudson Valley, to the mid 60s for eastern LI
and the SE coast of CT, which will have cooling onshore winds during
the afternoon.-- End Changed Discussion --
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
-- Changed Discussion --
Large scale numerical weather prediction models convey the upper
level jet as weak across the local region early into midweek. Then,
jet stream level winds increase as a quasi-zonal jet streak moves
into the area Thursday into Friday before shifting northeast of the
region next Saturday.
At the surface, high pressure moves farther offshore early into
midweek. 850mb temperatures are warming during this time period.
Synoptic pattern will be favoring low level warm air advection with
more SW to W flow. Dry conditions are forecast Monday night through
Wednesday.
Low pressure weakens and moves north of the Great Lakes
Wednesday night into Thursday. Its associated cold front approaches
the local region from the west. The cold front moves across the
local region Thursday night. Shower and convective activity is
forecast to decrease in coverage as the front moves farther east.
There is forecast of the potential showers and thunderstorms, slight
chance Wednesday night into early Thursday, higher chance Thursday
into Thursday night. Higher instability is forecast across the
interior and less to the east across the more marine low level
environment Thursday into Thursday evening. Therefore, locations
near NYC and to the north and west will have the higher chances of
seeing any rain showers and thunderstorms. 850mb temperatures do not
change as much between Wednesday and Thursday.
The local region will then be in between two low pressure systems
for Friday and Saturday of next week. The ECMWF recently trended
farther south and weaker with a wave of low pressure for next
Saturday. There is uncertainty in this timeframe and some
fluctuations of the low positions and thereby some rain potential
for the local area are possible with subsequent forecasts. Forecast
currently has slight chance of rain showers for much of the region
but some areas forecast to have relatively higher chance late Friday
night and Saturday but only between 25 and 30 percent.
Surface high temperatures are forecast to range from the upper 60s
to lower 80s for a majority of the region Tuesday, Wednesday and
Thursday. Relatively cooler high temperatures are forecast along the
immediate shore and the Twin Forks of Long Island, more within the
60s. High temperatures are forecast to trend downward slightly for
Friday (more in the 70 to 80 range) and next Saturday (mostly in
the upper 60s to mid 70s).-- End Changed Discussion --
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
Weak high pressure remains along the northeast coast and into
the mid Atlantic through Sunday afternoon. A weakening trough
of low approaches from the west, and dissipates late tonight.
Conditions remained varied across the region, with MVFR east of
the New York City terminals, and VFR at the New York City
terminals and north and west. There is a chance of MVFR at the
western terminals with scattered light rain into early this
evening. During the early evening MVFR is expected to develop
throughout the area, with KGON becoming IFR. Brief IFR will be
possible at KISP toward Sunday morning. Areas of rain and
drizzle will be possible this evening and into early Sunday
morning.
Conditions may begin to improve toward 18Z Sunday. Moderate
confidence in the forecast, with timing uncertainties with
ceilings lowering.
Winds generally remain 10kt or less from the northeast
..NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Scattered MVFR ceilings are possible late afternoon with light
rain, then becoming MVFR. Moderate confidence with the timing of
lowering ceilings this evening.
OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY...
Sunday afternoon...MVFR early, then becoming VFR, except KGON
remaining MVFR. Becoming MVFR at night.
Monday...MVFR early morning, then VFR.
Tuesday-Wednesday...VFR.
Thursday...VFR, a chance of MVFR with showers and thunderstorms.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
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Sub-advisory conditions currently anticipated across all local
waters through the middle of next week. However, with an
approaching cold front Wednesday into early Thursday and its
passage Thursday night, wind gusts will be reaching around 20
kt. Ocean seas forecast will be in the 3 to 4 ft range.
Conditions could trend more rough in subsequent marine forecasts
with higher ocean seas and higher wind gusts. Therefore would
not rule the possibility of SCA conditions in this time period
of Wednesday through Thursday night.-- End Changed Discussion --
&&
.HYDROLOGY...
There are no hydrologic issues through the middle of next week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JC/JM
NEAR TERM...JC
SHORT TERM...JC
LONG TERM...JM
AVIATION...MET
MARINE...JC/JM
HYDROLOGY...JC/JM