Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
923 PM EST Friday Nov 27 2015
a cold front over the eastern Great Lakes this evening will
approach late tonight and move across the area Saturday morning.
The front will drop slowly south toward the Middle Atlantic States
through Sunday as a wave of low pressure passes to the south. High
pressure will build in from the north from Sunday night into early
next week. A low pressure system will impact the region Tuesday
into the middle of the week. High pressure returns for the end of
Near term /until 6 am Saturday morning/...
forecast remains on track. Will update hourly grids to reflect
latest surface observation.
The northern branch of the polar jet will send a cold front over
the eastern Great Lakes toward the area late tonight...moving into
the lower Hudson Valley and interior southern CT by daybreak. Jet
energy is displaced north of the area with only weak frontal
convergence. The frontal passage will initially be dry with the
possibility of light Post-frontal rain on Sat.
Expect another mild night with increasing clouds late this
evening. Lows will be 45 to 50...which is about 10 degrees above
Short term /6 am Saturday morning through Saturday night/...
cold front crosses the coast by late Sat morning with no rain.
However...Post-frontal clouds and spotty light rain will be
possible by early after due to weak overrunning of the cooler air
slowly filtering in at the low levels. Once again though...the
lift is weak and any rainfall should be light.
It will remain mild Sat...but several degrees cooler than the
record warmth of Friday...with highs ranging from the lower 50s
inland...to the the upper 50s at the coast.
On Sat night...any light Post-frontal rain will be confined along
the coast with better chances toward daybreak as weak low pressure
passes to the south over the Middle Atlantic States.
Sat night will be cooler...ranging from the lower 30s inland...to
the lower 40s at the coast. This is still above normal by 5 to 8
Long term /Sunday through Friday/...
surface cold front remains stalled to the south of the area on
Sunday. Southern sections of the region could see some showers as
there may be some weak lift...especially in the morning.
However...the main forcing will move slowly south with the cold
front...and therefore...probability of precipitation will decrease throughout the day
Sunday...becoming mostly dry by the late morning into the
Thereafter...high pressure builds in from southeastern Canada with
troughing aloft...providing dry...but cool conditions. The upper
level trough exits the area Sunday night into Monday as the center
of the high moves over New England.
Weak upper level ridging begins Monday night and the surface high
pressure moves into the Gulf of Maine. This will allow a warm front
to approach on Tuesday...pushing north of the region into Tuesday
night as low pressure over the middle of the country moves into the
western Great Lakes region and becomes vertically stacked. A weak
low pressure develops along the warm front Tuesday night into
Wednesday. There may be a round of some moderate precipitation
depending on the track of this low.
Associated cold front approaches and moves through Wednesday. There
are some timing differences between the 00z European model (ecmwf)...12z GFS...and
12z CMC. The GFS is more progressive while the European model (ecmwf) is about 6
hours behind. However...the new 12z European model (ecmwf) is now very similar to the
12z CMC...developing a weak low pressure along the cold front over
Maryland...then heading northeast and tracking in the vicinity of
the tri-state Wednesday night into Thursday. Although this low is
weak...it could spell out more in the way of quantitative precipitation forecast if it verifies.
High pressure builds in through the end of the week with a return to
As far as temperatures...cold air advection behind the cold front will usher in
cooler air for Sunday...and even cooler air on Monday. Highs will be
in the middle to upper 40s on Sunday...and lower to middle 40s on
Monday. Temperatures will warm into the 50s for a majority of the
area on Wednesday in association with warm air advection with the warm front...then
will come back down to near normal behind the cold front for the end
of the week.
Aviation /02z Saturday through Wednesday/...
no significant changes made to previous taf package.
High pressure continues to move offshore. A cold front will
approach tonight and move across the terminals Saturday morning.
VFR conditions expected through tonight.
SW winds 5-10 knots will diminish to 3-5 knots overnight...and will
veer to the west after midnight and into Saturday morning. Most
inland terminals will become lgt/vrb. Winds then become northwest...then
north during the day Saturday as the cold front moves across the
MVFR ceilings will develop during the day. Scattered showers possible late
in the afternoon with MVFR cigs/vsbys.
Outlook for 00z Sunday through Wednesday...
Saturday night...scattered showers with MVFR conds possible.
Sunday-Sunday night...MVFR possible in the morning with a chance of
showers. Otherwise VFR in the afternoon.
Tuesday...IFR possible in rain and fog.
Wednesday...MVFR or IFR possible in the morning with rain ending.
Small Craft Advisory for seas will remain up through Sat due building seas in a southeast
swell. Elsewhere...sub-sca conditions are forecast with winds 10
knots or less.
Winds should remain below 25 knots through much of the long term. They
are forecast to come near or slightly above 25 knots Wednesday night
into Thursday as the pressure gradient increases.
Waves should remain below 5 feet from Sunday through Tuesday with high
pressure in control. Seas build to 5 feet on Tuesday night and
continue to build into the middle of the week as a storm system
approaches. Waves diminish toward the end of the week as high
rainfall amounts Sat and Sat night will be light and less than
a tenth of an inch.
Low pressure could bring about 1/2 to 3/4 inch of rain Tuesday into
Marine...Small Craft Advisory for hazardous seas until 6 PM EST
Saturday for anz350-353-355.