Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
211 am EDT Friday Sep 19 2014
high pressure builds in from the north today...then moves off the
northeast coast Friday night into Sunday. A cold front will pass
Sunday night. High pressure will then build in until another front
passes Tuesday night.
Near term /until 6 am this morning/...
cold front has sunk south of the region early this morning with north/NE
flow in shot of cold air advection.
Mixed low-levels and developing scattered to broken stratus under
subsidence inversion will limit radiational cooling. Temperatures slowly
drop into the middle/upper 50s coast...into the 40s interior by
Short term /6 am this morning through 6 PM Saturday/...
upper ridge axis builds toward the northeast Friday morning and off
the coast Friday afternoon. The flow then become nearly zonal until
late Saturday as a weak shortwave begins to move out of the upper
Midwest. At the surface high pressure builds to the New England
coast by Friday afternoon then continues to track off shore Friday
night through Saturday. A northeast flow off the northern Atlantic
will keep temperatures down...below normal during Friday. Leaned
toward the cooler NAM guidance for highs. Mixing Friday and Saturday
will be limited to around 900 mb as strong subsidence remains across
the region. There may be some cloudiness Friday as some moisture
does get trapped under a surface inversion. Weak warm advection
begins to set up late Friday night and continues into Saturday...and
temperatures will begin to moderate.
For Friday...there will be a moderate risk of rip currents at
Atlantic Ocean facing beaches.
Long term /Saturday night through Thursday/...
the County Warning Area will be between low pressure over the ocean and an approaching
cold front Sat night into sun. This should keep the area dry. Warm aloft
but southerly flow at the surface should limit most places to the 70s to near
80. Without this onshore component...full mixing would produce
low-middle 80s. The timing of the front will be key to precipitation chances. The
NAM indicates a slower frontal passage...which is generally a preferred play
in the extended. All models indicate the precipitation should weaken as it
tracks eastward with the front overnight. Have hedged towards a slower
onset sun...but maintained chances through the night expecting the showers to
hold together at least with scattered coverage.
Hi pressure then builds in with fair weather Monday into Tuesday. The next cold front
late Tuesday/Tuesday night. Moisture is limited so kept a dry forecast. There
could be a few sprinkles out of high bases around 5k feet.
Mainly clear for the rest of the week with hipres building in.
The 1030s high builds over the region Wednesday night...so manually dropped
temperatures as guidance may be too influenced by climatology. Temperatures otherwise
a blend of the gmos25/mex/men through the extended.
Aviation /06z Friday through Tuesday/...
high pressure over eastern Canada builds southeast and off the New
England coast by this evening.
This will result in northerly winds veering around to the east/southeast by late
this aft/eve. Some early gusts up to 20 knots possible through 15z.
Forecast dilemma hinges on the development of a stratus deck
around 3-4 kft. Preference is to hold off at this time due to dry
low levels. This may become more of a factor late Friday night. There
is some guidance though which develops these clouds as early as
Outlook for 06z Saturday through Tuesday...
Saturday-Sunday...possible MVFR conditions each morning in
fog/clouds...improving to VFR by 15z.
Sunday night-Monday...chance of MVFR or below with scattered
showers. G20-25 knots Monday.
high pressure builds to the north. As the high builds in the
pressure gradient winds will increase from the northeast. Some
gusts on the ocean waters will be near small craft levels early
this morning. In addition seas on the ocean should build to
around 5 feet by Friday morning. As the center of the high moves
off the northeast coast during Friday afternoon wind and seas are
expected to diminish. A Small Craft Advisory remains in effect for
the ocean waters east of Fire Island Inlet late tonight through
Otherwise with high pressure over the waters wind and seas will be
below small craft levels Friday night through Saturday.
Marginal Small Craft Advisory winds possible on the ocean and S shore bays Sat evening
with southerly flow. Small Craft Advisory winds and seas develop behind a cold front Sun night
into Monday. The Harbor and western sound may remain just blw criteria. Chance
of Small Craft Advisory winds again behind another front Tuesday night into Wednesday.
no rainfall is expected through Saturday night. Basin average
rainfall of less the 1/4 inch expected Sun afternoon and night.
Marine...Small Craft Advisory until 6 PM EDT this evening for anz350-