Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
359 PM EST Thursday Dec 12 2013
high pressure will build east into the region for the rest of the
week. Low pressure will move across the Ohio and Tennessee
valleys Saturday and emerge off the middle Atlantic coast Saturday
night. The low then tracks northeast into the Canadian Maritimes
Sunday into Sunday night. High pressure builds for Monday. Then a
weak and quick moving frontal system affects the region Tuesday.
High pressure returns for Wednesday and Thursday.
Near term /until 6 am Friday morning/...
another quiet and cold night in store for the region as an Arctic high
pressure builds east. The high will remain slightly suppressed to
the south as a weak cold front dips down from a low pushing
through far southeastern Canada...keeping a westerly flow across
the area. Fairly dry airmass remains in place...so expecting any
precipitation associated with the front to remain to our north...though the
passing upper level trough could increase cloud coverage over
inland areas. This combined with increased winds will keep any
radiational cooling to a minimum. However...with 850mb temperatures still
around -10 degrees...we should still see a very cold night...with
overnight lows a good 10-15 degrees below normal...and most of the
region seeing wind chill values in the single digits.
Short term /6 am Friday morning through Friday night/...
surface high briefly retreats to the south as a weak cold front
pushes through the northeast Friday afternoon. The high builds
back up in the wake Friday night...bringing about the last drier
weather before the approaching low pressure system for the
weekend. Overall...expecting the passage of the front to be dry
with the persisting Arctic airmass keeping fairly dry air over the
region. The front along with a passing weak wave aloft could
trigger isolated flurries over interior portions of New York and CT late
in the day and early Friday evening. A period of dry weather then
sets in before light precipitation associated with the approaching low
tracking through the southeast begins to move in. Currently just
have slight chance with light snow by 12z Sat...depending on the
timing of the low could see a difference of precipitation start time.
However...confidence is there that any initial precipitation will be in the
form of light snow.
Cold weather remains the story through Friday as 850mb temperatures
remain around -10 degrees. Highs Friday will be a couple degrees
warmer...though still around 10 degrees below normal. Increased
cloud cover ahead of the approaching systems Friday night will keep
lows in the 20s along the coast...and in the upper teens inland.
Long term /Saturday through Thursday/...
southern stream shortwave moving out of the Southern Plains and into
the southeast will develop a surface low moving through the Gulf
Coast states. High pressure will remain to the north over
southeastern Canada and into the northeast. Cold Ari damning will
keep cold air east of the Appalachians into North Carolina.
Developing warm advection...and coastal front...along with
isentropic lift will result in precipitation developing by Saturday
morning. Cold air will be in place at the start for all snow. The
trend has been for a warmer solution with the evolution of the low
as the storm redevelops off the middle Atlantic coast late Saturday
into Saturday evening. All models are tracking the low just inside
the benchmark...40/70. Flow will be progressive and no upper closed
low associated with the system. Plenty of Gulf and Atlantic moisture
will be incorporated into the system. Most of the precipitation will
occur at the start...Saturday into the evening. As warmer air moves
into a transition to rain along the coast is likely and farther
inland will be a transition of snow...sleet...and freezing
rain...taking longer for the transition into the lower Hudson Valley
until late Saturday night. Quantitative precipitation forecast amounts vary with the models and
leaned toward the wpc and rfc guidance. Snowfall totals will be
least across Suffolk County New York with the highest across the
lower Hudson Valley...ranging from around 2 inches to 6 inches.
Precipitation type and timing transition will have an impact on snow
and ice totals. Still do not have high enough confidence of a 6 inch
snowfall inland and will not issue any watches at this time...and
looks like an advisory event at this time.
The low will move away on Sunday...with precipitation ending. Dry
weather returns briefly Sunday into Monday night. Then a quick
moving frontal system moves through for Tuesday. High pressure
builds in for Tuesday night into Thursday. Followed closely to the
current forecast and wpc guidance for Monday night through
Aviation /21z Thursday through Tuesday/...
high pressure will remain southwest of the region through tonight.
VFR through the taf period.
Northwest winds will back to west-northwest late this afternoon with a slight decrease
in speed. Winds continue to back to the west by early evening with
speeds around 10-15 knots could see some gusts to around 20kt mainly
during the evening at coastal terminals.
Tonight...winds remain from the west 10-15 knots with gusts into the
upper teens and lower 20s as the gradient tightens with a passing
low well north of the region.
New York metropolitan enhanced aviation weather support...
Detailed information...including hourly taf wind component forecasts
can be found at: http:/www.Erh.NOAA.Gov/zny/n90 (lower case)
Kjfk fcster comments: timing of wind shifts could be off +/- 2
Klga fcster comments: timing of wind shifts could be off +/- 2
Kewr fcster comments: timing of wind shifts could be off +/- 2
Kteb fcster comments: timing of wind shifts could be off +/- 2
Khpn fcster comments: timing of wind shifts could be off +/- 2
Kisp fcster comments: timing of wind shifts could be off +/- 2
Outlook for 18z Friday through Tuesday...
Friday night...MVFR or lower possible late.
Sat-Sat night...IFR or LIFR likely. Precipitation type should be mostly
snow north of Long Island Sound and interior NE New Jersey...and snow mixing
with or changing to rain at night at the NYC metropolitan and Long Island
terminals. East winds g20-30kt possible mainly from NYC east at night.
Sunday...lingering snow or rain showers into the afternoon...
becoming VFR from west to east during the afternoon.
Tuesday...chance of sub-VFR in snow showers
Small Craft Advisory in effect for all waters tonight through Friday with a
tightening pressure gradient with the high to our south and an
approaching cold front from the north. Gusts up to 30 kts will be
possible...especially Friday morning...with seas on the ocean reaching 4-6 feet
Friday. Conditions will start to diminish late Friday from west to
east as the high builds in behind the departing front.
Low pressure over the Ohio and Tennessee valleys will move off the
middle Atlantic coast Saturday night...passing south and east of the
forecast waters through Sunday as the low heads into the Canadian
maritime. Small craft conditions are likely across the forecast
waters Saturday night into Sunday night in association with the
low. Behind the low late Sunday into Sunday night there is a
potential for a brief period of gale force gusts on the ocean
waters. Seas will be slow to subside with small craft seas on the
ocean waters lingering into Tuesday night.
significant precipitation is likely Saturday into Sunday in
association with a coastal low. Liquid equivalent quantitative precipitation forecast ranges from
3/4 to 1 inch...falling mainly as snow across northern New Jersey
into the lower Hudson Valley and across southern Connecticut.
Dry weather returns Sunday night into the beginning of next week.
the New York City National oceanic and atmospheric administration all hazards weather radio station kwo35 has
been returned to service. However...if issues arise again due to
interference with the U.S. Coast Guard emergency broadcast
channel...the transmitter may need to be taken out of service. If this
does occur...a notice will be made to the public notifying them of
Marine...Small Craft Advisory from 7 PM this evening to 6 PM EST Friday
Small Craft Advisory from 1 am to 6 PM EST Friday for anz330-
Small Craft Advisory from 10 PM this evening to 1 am EST
Saturday for anz350-353.
Small Craft Advisory from 10 PM this evening to 6 PM EST
Friday for anz340-345.