National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 101956
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
356 PM EDT Mon May 10 2021

.SYNOPSIS...
-- Changed Discussion --
High pressure continues to build in at the through Tuesday night,
with a surface trough moving through Tuesday. High pressure builds into the area Wednesday into Thursday. Weak
troughs of low pressure move through Friday into the weekend, but
high pressure will largely dominate the pattern over the
northeast.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
-- Changed Discussion --
High pressure at the surface will continue to build into the
forecast area tonight. Meanwhile, the area will be at the base of a
500 hPa trough that will be over the Great Lake and Northeast U.S. A
cut off low over the northern Great Lakes will weaken as it heads
southeast toward southeastern Canada.

With some clouds and a bit of wind (5 to 10 mph across the tri-
state), expecting some radiational cooling, but it will not be
maximized, so temperatures will run near or just below normal for
this time of year.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
-- Changed Discussion --
The 500 hPa low will help to induce low pressure over the Canadian
Maritimes on Tuesday, while southern New England and northern mid-
Atlantic remains at the base of the 500 hPa trough. A surface trough
looks to pivot around the low and into our area in the afternoon.
This could set off some showers during this time frame. The cold
pool aloft and surface heating will aid in destabilization with
steeper lapse developing in the lower to middle levels of the
atmosphere. However, a lack of any real strong forcing mechanism
will likely limit shower activity to slight chance. Additionally,
lack of any CAPE (surface or elevated) precludes the mention of
thunder, but the development of a thunderstorm somewhere in
the forecast area cannot be totally ruled out.

Any shower activity will end at or around sunset Tuesday evening.
Dry conditions are expected thereafter. Clouds will also diminish
through the night. Though continued light, winds will remain a bit
elevated overnight (5 to 10 mph and perhaps a few mph higher along
the coast). Once again, radiational cooling will not be maximized,
but better chances for cooler temperatures related to this would be
inland where winds will be a bit lighter. Some frost is possible in
these areas. However it looks to isolated to even mention in the
forecast as again, there will be at least some wind in these
locations.
-- End Changed Discussion --

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
There has not been too much change in the overall thinking in the
long term. A large upper level low and trough will be moving off the
New England coast on Wednesday. Its associated surface troughing may
linger over the area until evening when it shifts offshore and high
pressure begins to build in from the west. The surface high will
continue building in through the remainder of the week as ridging
takes shape aloft. However, the ridging is is likely to weaken on
Friday as the ensemble means indicate a split flow pattern setting
up aloft. The northern stream will remain displaced across southern
Canada. A series of southern stream shortwaves look begin to
approach on Friday and then possibly continue moving over or just
south into the weekend. High pressure will largely dominate the
surface pattern over the northeast, but the shortwaves aloft will
lead to weak surface troughs moving across each day. Ridging may
return early next week.

Overall, the latest NBM looks good for the long term. Will maintain
slight chance to low end chance PoPs for showers Friday into the
weekend, mainly in the afternoon and evening. Instability looks
minimal, but there is indicated of an increase in MLCAPE on Sunday.
Have maintained the previous mention of slight chance of thunder,
mainly away from the immediate coast.

Temperatures start out below normal Wednesday and then return to
near normal on Thursday and Friday. Temperatures should then average
near to above normal this weekend. The coolest readings should lie
near the immediate coast, especially late in the week and next
weekend due to sea breezes. Cloud cover associated with the series
of shortwaves late in the week may also impact temperatures.
-- End Changed Discussion --

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
-- Changed Discussion --
Weak high pressure builds in from the west through tonight.

Mainly VFR through the TAF period. There may however be a few
locations that observe conditions briefly fall back to MVFR for an
hour or so at locations north and east of NYC.

Winds N-NE around 10kt. A few gusts to around 18kt are possible at
the New York metro terminals until late afternoon. Winds may become
westerly late in the day into this evening, and then back to NW
under 10kt tonight. Seabreezes have developed along the Connecticut
coast.

    ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...

Amendments possible for wind directions. The NYC terminals may
become more westerly than forecast late this afternoon.

.OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY...
.Tuesday and Wednesday...VFR. W-NW wind G20-25kt.
.Thursday and Friday...VFR.
.Saturday...Mainly VFR. Chance of afternoon showers west of NYC.

Detailed information, including hourly TAF wind component forecasts,
can be found at: http:/www.weather.gov/zny/n90
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
With buoy 44065 reading less than 5 ft, the SCA for the western
ocean zone was canceled. 5 ft seas will continue over the central
and eastern ocean zone will continue overnight. The central
ocean zone may fall below 5 ft just after midnight, while the
eastern one will continue through the night.

Winds increase on Tuesday as low pressure over the Canadian
Maritimes strengthens. This will increase the pressure gradient
over the waters. Gusts of 20 kt are expected. There may be
occasional gusts to 25 kt across most waters. There is a chance
that a SCA may be needed, but confidence was not high enough to
issue one now.

Wave heights may build to 5 ft on the eastern ocean zone, and
the SCA may need to be continued into Tuesday if this trend
continues.

Winds and waves diminish Tuesday night.

Lingering SCA gusts are possible on the ocean waters Wednesday
morning. Overall, winds and seas will be subsiding on Wednesday with
much of the day below SCA levels. Thereafter, winds and seas should
remain below SCA levels on all waters through Saturday with a
general weak pressure gradient in place.
-- End Changed Discussion --

&&

.HYDROLOGY...
-- Changed Discussion --
No hydrologic impacts are expected through the weekend.
-- End Changed Discussion --

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 10 AM EDT Tuesday for ANZ350-353.
-- End Changed Discussion --

&&

$$
SYNOPSIS...JP/DS
NEAR TERM...JP
SHORT TERM...JP
LONG TERM...DS
AVIATION...BC
MARINE...JP/DS
HYDROLOGY...JP/DS