Area Forecast Discussion
Issued by NWS Upton, NY-- Remove Highlighting --
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FXUS61 KOKX 280626
Area Forecast Discussion
National Weather Service New York NY
226 AM EDT Tue Mar 28 2017
A nearly stationary front will sink to the south tonight, and
remain just south through Tuesday. Weak low pressure will also
approach on Tuesday, and pass south Tuesday night. High pressure
will build in for Wednesday and Thursday, and shifts offshore
Thursday night. A low pressure system will approach from the
Central states Thursday night, and impact the region Friday and
Saturday. High pressure will return for Sunday.
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Minor changes made to reflect current conditions. Continue to
monitor conditions for dense for overnight. 02Z observations
show very patchy dense fog. Visibilities over southern
Connecticut and Long Island should continue to gradually lower
through the night. However, there is still uncertainty for the
rest of the CWA, with only medium confidence for dense fog for
these areas. If dense fog does occur in the metro area,
climatology would favor after 06Z.
As of 23Z, the stationary front remains over the area. As a
wave of low pressure develops east of New England this evening,
the front should sink to the south, with winds becoming variable
and then settling in from the east late. This may bring
somewhat drier air in initially, but then with light winds and
nearly saturated low levels, dense fog is likely to develop,
especially across southern CT and Long Island where a dense fog
advy has been issued. Rain approaching from the west ahead of
the next weak wave of low pressure may prevent the fog from
becoming dense farther west, but this remains uncertain.
Lows tonight should range from the mid 40s invof NYC, to the
lower 40s most elsewhere, to the upper 30s across most of
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
Rain is likely over the area in the morning as a mid level
impulse moves across. There is some elevated instability, enough
to enhance rainfall rates but not quite enough for a mention of
thunder. Then we should see a relative lull in precip until
a weak low moves off the mid Atlantic coast Tue evening and its
associated upper trough move across. Once again there could be
enough elevated instability to enhance rainfall rates in the
evening, especially per the NAM which may be too unstable aloft,
so once again did not mention thunder. Also expect fog to
redevelop Tue night, though with the air mass not quite as
saturated and more of an offshore wind component, dense fog
appears less likely.
Highs on Tue should be 50-55 from NYC west, and in the upper
40s to near 50s most elsewhere. Lows Tue night should range from
40-45 NYC metro and Long Island, to the upper 30s inland.
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Typical spring pattern during this period with a deep closed low
emerging into the central US for the midweek...and then slowly
translating to the east coast by late week/weekend. The pattern then
repeats itself with another deep closed low emerging into the
southern plains by early next week.
Locally a northern stream trough over the region Wednesday slides
east Thursday...with model sensitivity and forecast challenge in the
interaction of the Central Plains closed low with a northern stream
shortwave over the Ohio Valley/Great lakes Friday before it slide to
the east coast Saturday. Appears to be increasing agreement in
GEFS/EPS and operational GFS/ECMWF/GEM on the opening shortwave
staying detached/far enough south for associated low pressure to
approach the Mid Atlantic and track over or just south of the region
Fri/Sat. Since this is still 4-5 days away will have to monitor this
interaction...as the low track could trend north if the interaction
w/ northern stream increases.
A low pressure system tracking to the south of the region would
spell potential for a period of wintry precip to start...a wind
swept rain...and at least minor coastal flood concerns Fri/Sat.
Farther north development/intensification would spell lesser
potential and duration of wintry precip, rain or coastal flooding.
Before then dry and seasonably mild conditions expected Wed and Thu
as Canadian high pressure builds into the region. In the wake of low
pressure...generally dry and mild conditions expected Sun/Mon with a
generally zonal upper flow and PAC airmass overspreading the area.
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
A front remains just south of the terminals and attempts to
push back north as a warm front on Tuesday.
Light and variable winds to light NE-ENE overnight and for
High clouds advecting in from the southwest resulted in a
momentary respite for western terminals with respect to
lowering ceilings and visibilities. However, expecting a push
west with low clouds and some fog. As of 06z obs LGA and EWR
showing a trend back down. TAFS reflect a more widespread and
consistent lowering of ceilings and visibilities towards 10z
with arrival of morning push. Confidence of exact timing of LIFR
conditions throughout the morning not of the highest confidence
with patches of rain forecast to move through which may result
in IFR conditions at times for some terminals.
Another area of rainfall will arrive later in the day and for
the evening. IFR to LIFR conditions are expected to prevail
until about 6z late tonight, with improving conditions
thereafter from west to east.
.OUTLOOK FOR 06Z WEDNESDAY THROUGH SATURDAY...
.Tue night...IFR or lower in rain/low clouds/fog.
.Wednesday...VFR. N-NW gusts 15-20KT.
.Friday...A wintry mix possible early north and west with IFR
conditions possible before a change to rain, otherwise sub VFR
conditions with rain elsewhere.
.Friday night and Saturday...Chance of rain with MVFR or lower
conditions. E winds G20-25KT at coastal terminals for Saturday.
SCA cancelled as seas have fallen below 5 ft. Earlier dense fog
advys were also dropped, but reissued for late tonight into Tue
morning as vsbys drop below 1 nm with a stationary front
sinking just to the south tonight.
Northwesterly winds will develop behind the cold front and then
increase into Wednesday and Wednesday night as high pressure builds
to the north. Minimal SCA conditions are possible across the
ocean waters Wednesday night into early Thursday.
The next likelihood for SCA and potential gale conditions will
be Fri/Sat as a low pressure/frontal system impacts the waters.
Additional rainfall of at least 1/4 inch and possibly up to 1/2
inch expected through Tue night. No hydrologic concerns
Astronomical tides will rise through Thu with the new moon.
Water levels may come close to minor flood thresholds during
high tide cycles Tue Night ahead of approaching low pressure.
A greater threat for minor coastal flooding could occur with
the Friday night high tide cycle, with the approach of a
potential low pressure system.
CT...Dense Fog Advisory until noon EDT today for CTZ005>012.
NY...Dense Fog Advisory until noon EDT today for NYZ078>081.
MARINE...Dense Fog Advisory until noon EDT today for ANZ330-335-338-340-