Area Forecast Discussion
Issued by NWS Upton, NY-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KOKX 281800
Area Forecast Discussion
National Weather Service New York NY
200 PM EDT SAT MAY 28 2016
A westward extension of the Bermuda High will over the area
through the weekend. A cold front approaches from the west on
Monday, then crosses the Tri-state Monday night. High pressure
builds down from Hudson Bay for the middle of the week. A cold
front approaches from the west on Friday.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --Some minor adjustments were made to dewpoints and temperatures to
better match observed trends. Temperatures were increased slightly
towards NYC and locations to the northwest. Isolated to scattered
convection north and west of NYC for this afternoon with
differential heating along higher terrain acting as a trigger for
convection with thermal trough setting up. Another day with a
large temperature gradient between coastal and inland locations
with the southerly flow.
An unseasonably warm day is in store as deep ridging builds aloft
and Bermuda high pressure remains over the area. Temperatures will
be in the lower 90s across NE NJ and the interior Lower Hudson
Valley. Southerly winds will increase this afternoon which will
likely prevent temperatures in the city and interior southern CT
from warming much above the middle 80s to near 90. Near the
coast, highs will reach the upper 70s and lower 80s.
Convection chances appear lower than on Friday as there is not much
of a trigger with deeper ridging over the area. Instability will be
largest away from the stronger sea breezes north and west of the
city so this is where any widely scattered convection may develop
late this afternoon. Best chance appears to lie across the NW
interior which ends up closest to surface boundary to the north of
There is a moderate risk for the meteorological enhancement of rip
current formation at Atlantic Beaches today.
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.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
Any convection that develops should dissipate with loss of daytime
heating this evening. Backdoor cold front to the north will not
make much progress south and will likely stall well to the north
and east. Do not see much of a trigger or support for any
shower/storms overnight so the forecast is dry after midnight.
Low temperatures will be close to ten degrees above normal in the
Ridging begins to break down aloft on Sunday as heights fall
through the day with an approaching shortwave from the west.
Forcing is weak during the day so will once again show best
chances for any convection north and west of the city where better
instability will reside. Moisture will be on the increase however
as southerly flow off the western Atlantic strengthens. Highs
should end up a few degrees cooler than Saturday with the stronger
southerly flow and a few more clouds in the afternoon.
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
The main focus of the long term is Sunday night into Monday as the
ridge continues to break down and shift east. A shortwave
approaches from the west Sunday night in combination with an
increasing southerly flow which will advect tropical moisture from
remnants of tropical system off the Carolinas. Precipitable
waters are progged to be near 2 inches and these values are close
to the maximum observed precipitable water for May 30 per SPC
Sounding Climatology. The region will also lie in the favorable
right entrance region of a 80-100 kt upper level jet and low level
winds will also increase.
Pattern recognition with all of these ingredients shows the
potential for a predecessor rain event during this time frame with
locally heavy rainfall. The biggest uncertainty lies in where
heaviest bands of rain will set up. Even with this uncertainty,
have increased pops to categorical late Sunday night into Monday
as all of the aforementioned ingredients come together. Have also
included mention of thunder, although instability will likely be
on the low side. See hydro section for more details.
The shortwave axis moves across the area late Monday into Monday
night which will push the deep moisture plume to the east ending
the rain. Cold front will likely be slower to move through the
area and may not completely clear the area until Tuesday.
Deep ridging builds over the northeast Wednesday and Thursday.
Surface high pressure should move across New England on Wednesday
and then set up over the Canadian Maritimes on Thursday. A cold
front approaches from the west in conjunction with a shortwave
trough. The trend in temperatures should be closer to seasonal
norms for the middle and end of next week.
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
-- Changed Discussion --High pressure will remain nearly stationary across the western
Atlantic through Sunday with a thermal trough across the interior
Another afternoon of S/SW flow with local seabreeze enhancements.
Similar to Friday afternoon, expect the development of a coastal
seabreeze jet around 20Z that will impact KJFK and kLGA. Gusts up
to 30 kt possible at KJFK. This may translate east and impact KISP
during the evening hours. SW winds diminish to less than 10 kt
Isolated to scattered convection this afternoon and early evening
primarily north and west of the NYC terminals. Have maintained
VCSH at KSWF through 00Z.
MVFR fog is possible late tonight at KSWF, with a low chance
across the remainder of the non-NYC terminals.
.OUTLOOK FOR 18Z Sunday through Thursday...
.Sunday Afternoon...Mainly VFR with afternoon seabreezes. Chance
of MVFR or lower in any isolated to scattered afternoon
showers/thunderstorms mainly for Lower Hudson Valley/interior S CT
.Sunday night-Monday...MVFR or lower likely. Showers/thunderstorms
could produce locally heavy rainfall.
.Monday night-Tuesday night...Becoming VFR Monday Night.
.Wednesday and Thursday...VFR.
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The marine forecast remains on track.
A weak to moderate pressure gradient over the region through
Wednesday will keep sustained winds to 15 kt or less over the waters
around Long Island. With no significant swells currently forecast
during this time frame, seas should remain below Small Craft levels
No significant widespread precipitation is expected through Sunday.
Rainfall amounts around one to one and a half inches are possible Sunday
night into Monday with locally higher amounts. Minor urban or
poor drainage flooding is possible from the heaviest rainfall.