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000 
FXUS61 KOKX 280251
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1051 PM EDT Mon Mar 27 2017

.SYNOPSIS...
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 TUESDAY 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
southern CT.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
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 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 /03Z TUESDAY THROUGH SATURDAY/...
A front remains just south of the terminals tonight and 
attempts to push back north as a warm front on Tuesday.

Light and variable winds or light NE-ENE tonight.

Conds as of 0245z are varying from VFR to VLIFR across the area
terminals. Expecting IFR or lower across all terminals during
the overnight hours. Fog expected to become more dense and 
widespread overnight. BKN-OVC deck near 7-8 KFT that formed 
just to the west near 02z is shifting in, and may delay or 
prevent low vsbys in fog primarily from the city and points 
west, and may actually help improve vsbys temporarily farther 
east.

For Tuesday, IFR or lower and fog to start, probably remaining 
IFR through the day. ENE winds 5-10KT.

Rain is possible primarily starting with late tonight.

.OUTLOOK FOR 00Z WEDNESDAY THROUGH SATURDAY...
.Tue night...IFR or lower in rain/low clouds/fog .
.Wednesday...VFR. NW gusts around 20KT. 
.Thursday...VFR.
.Friday-Saturday...Chance of rain with MVFR or lower 
conditions. E winds G25KT at coastal terminals.

&&

.MARINE...
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.

&&

.HYDROLOGY...
Additional rainfall of at least 1/4 inch and possibly up to 1/2
inch expected through Tue night. No hydrologic concerns
anticipated.

&&

.TIDES/COASTAL FLOODING...
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.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Dense Fog Advisory until noon EDT Tuesday for CTZ005>012.
NY...Dense Fog Advisory until noon EDT Tuesday for NYZ078>081.
NJ...None.
MARINE...Dense Fog Advisory until noon EDT Tuesday for ANZ330-335-338-
     340-345-350-353-355.

&&

$$
SYNOPSIS...Goodman/NV
NEAR TERM...Goodman/JP
SHORT TERM...Goodman
LONG TERM...NV

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