843
FXUS61 KOKX 201145
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
645 AM EST Thu Feb 20 2025
.SYNOPSIS...
-- Changed Discussion --
Low pressure off the Carolina coast deepens as it tracks well
east of the area into tonight. Thereafter, sprawling high
pressure over the mid section of the country builds in through
the weekend, remaining in control through Monday. A weak low
pressure system passes to our north Monday night into Tuesday.
High pressure builds back in for Wednesday.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
A 1000 mb surface low off Cape Hatteras deepens as it pulls off
to the north and east through tonight. Meanwhile, an upper low
swings over the region into this evening, with a weak inverted
surface trough extending back toward the region from the exiting
low.
Temperatures remain 10 to 15 degrees below normal for late
February, the morning starts out in the teens and low 20s across
the region, with highs this afternoon expected to remain below
the freezing mark, ranging from the mid 20s inland, to around 30
at the coast. A high cloud canopy thickens and lowers into late
day.
As the upper low swings through, steepening lapse rates and a
moistening column down to the sub cloud layer should instigate
snow shower development late this afternoon and evening. QPF is
light, under a tenth of an inch everywhere, closer to several
hundredths. Still, with the cold air mass entrenched, and SLRs
progged around 15:1, the snow could stick and accumulate
relatively efficiently if/where it does fall. With such little
liquid equivalent to work with though, amounts should be limited,
likely at or under half an inch. Localized amounts could approach
an inch, which remains a possible solution should coverage be a
bit more persistent as some hi res guidance is hinting. While
not a particularly notable event based on amounts, the expected
timing of this activity, in the late afternoon and early
evening, could pose some travel impacts and slick spots to the
PM rush. Still, some locales may not see any snow whatsoever, or
just a few flurries, largely staying dry and overcast instead,
especially into interior southern CT.
Clouds begin to thin out regardless overnight as the upper low
shifts offshore and drier air works in. Flow increases as the
exiting surface low deepens and tightens the pressure gradient
locally, which should preclude decoupling regionwide. Overnight
lows range from the teens inland, to lower 20s along the coast.-- End Changed Discussion --
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
Sprawling 1040 mb high pressure across the mid section of the
country builds into the area on Friday.
Blustery NW flow persists with the pressure gradient between
the building high and exited offshore low, and gusts toward 30
mph are expected much of the day, adding a chill to the already
below normal temperatures. Some coastal locales may sneak above
the freezing mark by a degree or two in the afternoon, otherwise,
upper 20s to around 30.
Flow relaxes into Friday night as the high builds closer, and
mostly clear skies prevail as temperatures fall into the teens
overnight.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
The upper flow will be mainly zonal Saturday into Sunday night,
with a very weak, low amplitude, trough moving through Saturday
night with surface low pressure passing well to the north, as
high pressure remains in control, centered to the south. With
little upper support and little moisture no precipitation is
expected.
A more amplified trough, accompanied with a vort max, passes
mainly to the north Monday night, quickly followed by another
trough and vort max for Tuesday. With some uncertainty with the
timing and strength of this trough, have only slight chance
probabilities Monday night through Tuesday. Zonal flow returns
for Wednesday. With mild air in the area, with temperatures 5 to
10 degrees above normal Monday night through Wednesday, the
precipitation will be mainly light rain showers, with light snow
showers inland.-- End Changed Discussion --
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
Low pressure passes well south and east of the area today into
tonight. An upper level low, and surface trough, will cross the
area tonight. High pressure builds in Friday.
VFR with a period of MVFR and possibly IFR in light snow
showers late this afternoon into tonight, 21Z to 06Z, and
maintained a PROB30 for the lower conditions in snow. There is
some timing uncertainty with the onset, and may be an hour
earlier. Up to a half inch of snow is possible.
Winds N to NW early this morning, then a NW flow is expected
through the remainder of the forecast. Gusts develop later this
afternoon, and may be more occasional until toward 00Z. Winds
and gusts increase overnight, with occasional gusts 30-35 kt.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments for timing of snow and lowering conditions late this
afternoon into this evening. Occasional gusts late this evening
into tonight may gust in excess of 30 kt.
.OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
Friday: VFR. NW winds G25 kt.
Saturday and Sunday: VFR.
Monday...Mainly VFR. A slight chance of MVFR in rain/snow
showers at night.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Lighter winds and seas maintain sub Small Craft Advisory (SCA)
conditions on all waters today. By this evening, increasing flow
behind passing low pressure well offshore returns SCA conditions
to all waters as NW gusts 25 to 30 kt develop tonight and persist
thru Friday. Seas on the ocean build toward 5 to 7 ft during this
time as well. Winds are expected to lighten below advisory criteria
Friday evening on non ocean waters, and by Friday night on the
ocean.
Sub advisory conditions then prevail Saturday through Monday,
however, Saturday night gusts on the ocean waters may briefly
near SCA levels as low pressure passes well to the north and W
to SW winds increase. A persist WSW flow Sunday night into
Monday night will allow ocean seas to build and by late Monday
night into Tuesday seas may reach 5 to 6 feet.
&&
.HYDROLOGY...
No hydrologic impacts are expected through the middle of next week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 6 PM this evening to 6 PM EST Friday
for ANZ331-332-335-338-340-345-350-353-355.
&&
$$
SYNOPSIS...DR/MET
NEAR TERM...DR
SHORT TERM...DR
LONG TERM...MET
AVIATION...MET
MARINE...DR/MET
HYDROLOGY...DR/MET