Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Albany New York
631 am EST Thursday Dec 12 2013
a narrow ridge of high pressure will attempt to build into the
region today. This should reduce the lake effect snow showers and
squalls for a period of time today. However...another clipper
system will approach tonight and cross the region Friday morning.
This will touch off another round of lake effect activity and the
chance for more snow showers across the region. The snow showers
end rather quickly through Friday morning as this front slides
south of the region. A winter storm is forecast to impact the
region this weekend.
Near term /until 6 PM this Evening/...
Lake effect activity has quickly dissipated on the regional radar
as combination of the subsidence inversion lowering /as seen in
the upstream soundings from kbuf-kdtx/ and surface anticyclonic
flow increases. So most of the daylight morning hours should
remain rather dry /residual flurries to our west/. A variety of
sky conditions can be expected today with more clouds across the
terrain as highs remain in the 20s for most locations. As seen in
the water vapor loop...next wave was approaching from the Great
Lakes region. The approach of this wave will accomplish several
things for later this afternoon. The boundary layer flow will
become west-southwest as inversion heights rise with Delta T/S
remaining favorable for Lake Ontario response. Per hrrr/hireswrf
experimental reflectivities...lake effect snow should redevelop
and per the low level flow trajectory...the bands of snow will
move across the Tug Hill region and perhaps into northern Herkimer
County. Per cstar research of lake effect inland extent...with
little contribution from upstream lakes...bands of snow are
forecast to remain within 50 miles of the Lakeshore which stops it
just short of our County border. So we will keep probability of precipitation below likely
for now and watch trends through the day.
Short term /6 PM this evening through Friday Night/...
Lake effect snow watch posted for northern Herkimer County...
the aforementioned frontal boundary will be approaching the
central Great Lakes region tonight. Forecast bufr profiles point
toward increase low level lapse rates...rising inversion heights
and rather moderate to High Lake induced convective available potential energy for another round
of lake effect snow. Per cstar research...lake effect inland
penetration is forecast to fluctuate between 50 and 80 miles. The
main challenge remains shear as magnitudes could disrupt
organized bands. Felt confidence levels along with surrounding
weather forecast office/S were close to raise another watch for just northern Herkimer
County. Elsewhere...clouds on the increase with the increase
chance for snow showers and perhaps a couple of squalls as this
On Friday...this front is expected to slide southeast and just
clear our southern zones by days end. This front will quickly
shift the winds toward a more northwest trajectory Friday morning.
This will quickly shut Down Lake effect activity as inversion
heights lower and drier air advects across the lakes. Layer relative humidity
values remain rather moist which only continues into Friday night
as we begin to watch the winter storm unfold. Broad isentropic
lift increases which also coincides with low level ageostropic
flow to keep our northern portions of the County warning forecast area mainly dry through
Friday night. Where the cpd/S are expected to drop for the chance
of snow will be mainly south and west of Albany.
Generally followed a blended MOS approach as values were not too
much different given our synoptic pattern set up.
Long term /Saturday through Wednesday/...
potentially significant winter storm impact this weekend...
Sat-Sun morning...there is still a good consensus from deterministic
and ensemble guidance for a storm to track off the Long Island and
New England coast over the weekend. The origins of the system are
still over the Pacific...resulting in lots of uncertainty in the
forecasted track and potential impact to the region. The exact
track will determine how far north the heavier precipitation gets.
At this time...per HPC pmdhmd discussion...the 00z/12 NAM appears
too far north with the track and is considered an outlier...as it brings
some middle level warming and the possibility of mixed precipitation as far north
and west as the capital region. Otherwise...there is a good consensus
that there will be a period of enhanced isentropic lift and
frontogenesis associated with warm advection Saturday through
Saturday night...perhaps lingering into Sunday morning. Some
headlines may be necessary due to potential snow amounts...since
most areas should be cold enough for snow. The storm should be
moving rather fast...with the most persistent f-general and moisture
convergence appearing to be mainly across eastern New England at
this time. There could be a zone of mixed precipitation in southern
areas...and have acknowledged this possibility with with mention of
sleet/freezing rain for southern Litchfield Colorado CT late Sat nt. Will
have to watch for the possibility of middle level drying occurring Sat
nt...which could limit overall quantitative precipitation forecast/snowfall amts. As for
temperatures...clouds and wet bulbing of snow falling through initially dry
low level air should keep temperatures rather cold through the
period...with maxes only reaching the middle teens to Lower/Middle
20s...and overnight mins falling into the teens...with single digits
possible for northern areas...and near 20 for extreme southern areas.
Sun afternoon-Monday...snow showers may persist across the region
early Sun afternoon...before transitioning into a lake effect snow
regime for sun nt into Monday am. So...likely probability of precipitation early Sun afternoon
for most areas...then acknowledging chances for snow showers Sunday
night through Monday morning for areas bordering the southern
Adirondacks and eastern Catskills. As for temperatures...expect teens and
20s for most areas for maxes...except for some lower 30s across
portions of the middle Hudson Valley and northwest CT...with sun nt/Monday am
mins falling into the single digits and lower teens for most
areas...with even colder temperatures possible should skies clear out.
Monday nt-Tuesday nt...warm advection associated with the approach of a
clipper type low will produce clouds and some light snow or snow
showers for areas near and north of Interstate 90 on Tuesday...with
light accums possible. Southern areas should remain generally
dry...with just some clouds at times. South to southwest winds will
increase...with Tuesday maximum temperatures reaching the Lower/Middle 30s in
valleys...and 25-30 for higher elevations. Overnight mins Monday nt/Tuesday
am should fall into the single digits and lower teens...and possibly
colder depending on how long skies remain clear. Slightly milder
temperatures are expected for Tuesday nt/Wednesday am...with mostly teens expected.
Wednesday...some lake effect snow showers in the wake of the clipper
system will be possible...so slight chance/chance probability of precipitation are indicated for
north/west areas...and dry elsewhere. Expect maximum temperatures to reach the 20s for
higher elevations...and lower 30s for valley areas.
Aviation /12z Thursday through Monday/...
mainly VFR conditions are expected through at least late morning.
Then...will have to watch for possible snow showers/flurries to
develop from southwest to northeast...as some remnants of the lake
effect band/moisture start to retreat back into the region. Expect
mainly scattered light snow showers/flurries...especially late this
afternoon into early tonight at kalb/kpsf and kgfl. Can not rule out
some periods of MVFR of IFR visibilities in any slightly heavier snow
showers...but confidence too low at this time for any mention in
Winds will be west to northwest through sunrise...at 5-10 knots.
Winds will back slightly...into the west to southwest at 5-10 knots
by middle morning Thursday into Thursday night...with some gusts of 10-20 knots
possible. West to southwest winds will persist overnight at 5-10
Friday night: low operational impact. Slight chance of snow.
Saturday: high operational impact. Definite snow.
Saturday night: high operational impact. Definite snow.
Sunday: high operational impact. Likely shsn...sn.
Sunday night: low operational impact. Slight chance of shsn.
Monday: no operational impact. No sig weather.
no Hydro related concerns are expected through the remainder of this
week and into the weekend. The precipitation that occurs will be
in the form of snow...except a wintry mix is possible over the
weekend for areas along and south of Interstate 90.
For details on specific area rivers and lakes...including observed
and forecast river stages and lake elevations...please visit the
advanced hydrologic prediction service /ahps/ graphs on our website.
New York...Lake effect snow watch from 6 PM EST this evening through
Friday afternoon for nyz032.
For the latest updates...please visit our webpage at