Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
946 PM EST Thursday Dec 25 2014
high pressure builds over the southeastern U.S. Through Saturday. A
cold front crosses the tri-state on Sunday. This front stalls out
well to the south of Long Island...as cold Canadian high pressure
builds in from the west throughout next week. Multiple lows pass
along the front for the early part of next week.
Near term /until 6 am Friday morning/...
forecast on track with main adjustment to slow temperature cooling rate
until after winds decrease after midnight.
Skies becoming clear and gusts diminishing through midnight as
high pressure builds in from the west.
Lows are blended NAM and GFS MOS which had nearly no spread.
Short term /6 am Friday morning through Saturday/...
ridging aloft with above normal temperatures for the period.
Have forecast above NAM/GFS MOS based on nearly full sun and 552 dm
thickness for Saturday. Also...ensemble MOS from 00z..ekd MOS and
GFS parallel all suggesting 50-55. Looks like a great day to be
outside with light winds.
Long term /Saturday night through Thursday/...
overall...in the middle to upper levels...the ridge flattens going
into early next week. This leaves a zonal flow through midweek and
then a trend towards more of a trough across the northeast towards
the end of the week.
At the surface...a weak parent low moves through southeast Canada
and into the Canadian Maritimes Sunday...dragging a cold front
across. The front then stalls well south of Long Island going into
early next week with multiple areas of low pressure riding along
the front. One big feature to note next week is the very strong
high pressure moving into the northwest U.S. Likewise...a very
cold source of air will be moving into the northwest U.S. This
airmass gradually moves south and east through the week.
In terms of sensible weather...an increasing chance of
precipitation late Saturday night into Sunday associated with the
cold frontal passage. The amounts are light...with less than a
quarter of an inch likely. Much of it is forecast to fall during
the day Sunday into Sunday evening...so this allows most precipitation to
be rain showers especially near the coast. Interior will probably
have more chance of seeing some snow showers. The next precipitation is
only slight chance for Monday into possibly Monday evening. Colder
air in place here but amounts very light...a few hundredths of an
inch or less. The precipitation will be a mix of rain and snow...but
again with aforementioned light amounts...no accumulation of any
snow is forecast.
Temperatures overall a colder trend. Above normal highs
Sunday...near normal Monday...and below normal thereafter.
Aviation /03z Friday through Tuesday/...
high pressure will continue to build in.
Gusty west flow will continue to diminish through midnight...then
remaining generally under 10 knots till daybreak.
VFR on Friday...with westerly flow gradually backing SW late in the
day. Few-scattered 2 kft cumulus likely.
Outlook for 00z Sat through Tuesday...
Sunday...MVFR with chance of light rain.
Tuesday...low confidence VFR.
winds and seas continue to gradually subside through the
overnight...with remaining Small Craft Advisory conds across central and eastern
ocean waters falling below by early Friday morning.
Sub-Small Craft Advisory conditions are anticipated on Friday into next week. The
only exception would be Sunday when 5 feet seas are forecast for the
ocean southeast of Montauk Point. There is uncertainty associated
with this and is dependent on how the cold front and parent low
trend with the response of the pressure gradient.
dry through Saturday night with no significant precipitation expected
from Sunday-Wednesday at this time.
Marine...Small Craft Advisory until 5 am EST Friday for anz350-353.