000
FXUS61 KOKX 111057
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
657 AM EDT Thu May 11 2023
.SYNOPSIS...
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High pressure builds south and west of the area through today,
becoming based offshore tonight into Friday. A cold front
approaches from the north Friday night with a weak wave of low
pressure approaching the local region from the west as well.
Both of these will be moving south of the area early
Saturday. High pressure builds in on Sunday, followed by a cold
frontal passage late Tuesday into Wednesday.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Adjusted hourly temperatures and dewpoints as well as cloud
coverage to better match observed trends. The forecast overall
remains on track.
In the mid levels, a shortwave riding southeast along the edge of a
ridge will be approaching coastal New England this afternoon.
Without much of a source of moisture with much westerly flow, kept
the forecast dry as most of the positive vorticity advection stays
east of the forecast region late this afternoon. Just have an
increase in clouds to indicate the approach of the shortwave.
At the surface, trough development expected within the region today
with high pressure centered south and west of the area. This will
allow for more westerly winds across NE NJ, Lower Hudson Valley, NYC
and Southern Connecticut but more southerly flow for Long Island and
coastal Connecticut.
Used the NBM for high temperatures for the coastal areas and the NBM
50 percentile elsewhere. The sea breeze will keep coastal areas
relatively cooler. Highs forecast range from the low to mid 70s
along much of the immediate coast to lower 80s within NE NJ.-- End Changed Discussion --
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
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The mid level shortwave passes southeast of coastal New England this
evening with much of the associated positive vorticity advection
passing offshore as well. Again, this enhanced energy and lift will
be east of the region, so kept a dry forecast this evening.
Any lingering clouds decrease mid to late evening, as there will be
some slight ridging in the mid levels. At the surface, some slight
rises in surface pressure as high pressure builds in slightly from
the west. Winds at the surface will lighten allowing for radiational
cooling.
Took the NBM and consensus of MOS for low temperatures forecast
tonight, ranging from the upper 40s to lower 60s.
For Friday, another mid level shortwave passes to the north and
east of the region with some slight ridging building in thereafter.
This will be brief though as a weak wave of low pressure approaches
from the west Friday night into Saturday, bringing some associated
rain showers. The wave of low pressure will be along a cold front
which will be approaching Friday night with both of these passing
south of Long Island early Saturday. Not much rain is expected,
less than a half inch, with heaviest of rain passing well south
of the area. With some small surface instability indicated by
forecast models Saturday, also put in a slight chance of
thunderstorms.
Stronger high pressure begins to build in from the north going into
Saturday night. Drier weather will return with dewpoints falling
into the upper 30s to lower 40s by early Sunday. Lows Saturday
night trend cooler than the previous night, ranging from the upper
40s to upper 50s.
Similar synoptic setup for Friday with daytime trough development
will have similar winds to the previous day but with a tighter
gradient, the magnitude and therefore the wind speed will be higher.
850mb temperatures trend a few degrees higher than the previous day.
Likewise, high temperatures forecast will be several degrees higher
than the previous day with the greater warm air advection. Friday`s
forecast high temperatures will be the highest of the week with some
locations getting close to their respective daily record highs for
May 12th. See climate section for more details.
Also trending up will be the dewpoints and by late Friday night for
the coast, low level relative humidity will be getting close to
saturation. Especially with any lulls in the rain shower activity
plus surface winds remaining relatively light, this will allow for
at least some patchy fog to develop. This has been put into the
forecast for eastern coastal locations as well as some portions of
the Lower Hudson Valley.
With abundant clouds and rain showers in the early part of the
day, expecting cooler temperatures Saturday, mainly in the upper
60s to upper 70s range.-- End Changed Discussion --
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
High pres building in on Sun with dry wx. Temps abv climo due to
good mixing. Based on winds aloft, the sea breeze should hold off
until late except for the immediate south shores.
The GFS has trended swd with the next sys on Mon, albeit not as far
south as the ECMWF soln. NBM pops keep the cwa dry outside of some
20 pops on the ocean, and this was followed. Favorable wly component
winds should allow most areas to get into the 70s.
A cold front drops out of Canada and reaches the area in the late
Tue into Wed time period. The GFS is slightly slower than the ECMWF,
and the NBM pops help to cover these differences. The sys will be
moisture starved with only nrn stream moisture to work with. Temps
abv climo on Tue with good prefrontal warming. A little cooler on
Wed, but good mixing should counterbalance h85 temps in the low
single digits approaching 0C by Wed ngt. Highs therefore in the 60s
to around 70 per the NBM look reasonable.
Dry Thu with high pres building in and a dry airmass in place. Went
with the NBM for temps for now, although they might be trending too
close to climo and slightly too warm as a result.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
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A broad area of high pres will remain over the area thru Fri.
VFR thru the TAF period.
Light and vrb winds become WNW up to 10 kt today. A period of
gusts possible from the 18z to 22z timeframe for a few of the
city and coastal terminals. Maintained tempos at LGA and EWR for
this. A sea breeze should develop, but is likely only for KJFK,
KISP, KBDR and KGON with W winds becoming more SW. Increased
wind speeds at JFK for this hybrid enhanced onshore wind. Winds
become light and vrb again aft 3Z Fri, then increase to around
10 kt aft 14Z Fri.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of sea breeze may be off by 1-3 hrs at JFK today.
...OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
Friday...VFR.
Saturday...Possible MVFR in a chance of showers.
Sunday...VFR.
Monday...VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
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Expecting mainly sub SCA conditions to continue through
Saturday night with not much tightness in the pressure gradient.
Any 25 kt gusts on the ocean waters this afternoon into early
evening as well as Friday afternoon into early evening are only
expected to be occasional.
Winds and seas are generally expected to remain blw sca lvls on all
waters Sun-Wed. Exception is Mon ngt into Tue, where seas may build
to around 5 ft on the ocean due to sw flow ahead of a cold
front.-- End Changed Discussion --
&&
.HYDROLOGY...
No hydrologic impacts are expected through Wednesday of next
week.
&&
.CLIMATE...
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Location.........May 12th Record High/Year
Newark NJ..........92/1959
Bridgeport CT......88/1991
Central Park NY....93/1881
LaGuardia NY.......88/1991/1948
Kennedy NY.........89/1991
Islip NY...........87/1991-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...12/JM
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...12
AVIATION...12
MARINE...12/JM
HYDROLOGY...12/JM
CLIMATE...JM