Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Buffalo New York
731 am EST Wednesday Mar 4 2015
colder air will overspread the region today into tonight...while
strong high pressure settles south across the center of the country.
This will eventually lead to some all too familiar frigid weather
tonight and Thursday when temperatures will average 15 to 20 degrees
Near term /through tonight/...
a stalled frontal boundary lies just to the south of the forecast
area this morning crossing western PA into south-central New York.
North of this boundary low level moisture has thinned bringing an
end to the threat for freezing drizzle and the Winter Weather
Advisory. Low cloud cover will remain as a ribbon of moisture from
the Mississippi Valley streams across New York state. Temperatures
across the area are ranging from around 30 in the southern tier and
east of Lake Ontario to the middle 30s toward The Finger lakes.
This afternoon into this evening a moisture starved Arctic
front...presently over the central Great Lakes...will drop south
across western and central New York. This will set of a sharp
temperature drop from the middle and upper 20s through the teens and
into the single digits across the southern tier and North County
overnight. The cold air with the front brings a temperature profile
supporting snow showers but with the dry airmass the front is
moving through have held this at low chance. Winds will become
northwest behind the front as the boundary presses toward the PA
line. A weak band of lake effect snow is possible south and
southeast of Lake Ontario as the colder air steepens low level lapse
rates. Only a trace to a dusting of snow possible along the Arctic
front with up to an inch south and southeast of Lake Ontario in weak
Short term /Thursday through Friday night/...
another surge of Arctic air will push into the region during the
period...as yet another round of upper troughing sets in over the
Great Lakes. The leading edge of this much colder air will be
working into the area today...in the wake of departing low pressure.
However...the core of coldest air looks to drop in aloft Thursday
and Thursday night...holding firm into much of Friday. This incoming
air mass will send temperatures some 15 to 20 degrees below normal.
From a sensible weather standpoint...the main concern this period
will be the cold temperatures...with an increasing concern for
dangerously cold wind chills developing Thursday night into Friday
morning. Wind chill headlines may be needed in later forecasts as
values drop into the 10 below to 25 below range.
A broad west/northwest flow across the area Thursday combined with
850 mb temperatures diving toward -22c and at least a spoke or two
of deeper moisture working through the area should deliver scattered
to numerous snow showers...especially southeast of the open waters
of Lake Ontario. Accumulations should be held in check both by ice
cover and the very cold nature of the airmass...but nonetheless...
there still should be minor local accumulations. Time of year will
favor diffuse banding...with a more cellular nature beneath the
upper cold pool.
As mentioned above temperatures will be well below normal. Daytime
temperatures Thursday likely remaining in the teens and only
improving to around 20 for Friday. Overnight lows Thursday night
from zero to 10 below. There will be a gradual retreat of the Arctic
air Friday night as we await our next upper wave working toward the
area with lows holding in the teens.
Long term /Saturday through Tuesday/...
the models are looking more consistent for the middle week system with
a lot of ridging aloft and a wave running up the front to our west.
This would allow for warmer air to flood across the Ohio Valley and
eastern Great Lakes. Still not very comfortable with the exact track
and strength of the surface low and the specific timing. The warm up
will be slowed to some extent by the extensive snow cover but there
certainly seems to be an increasing chance that we will be on the
warm side of the system.
Will continue the trend of nudging up forecast temperatures and
allowing for a change to rain. Will not go as warm as it could get
just yet given that we are still 5/6 days away and no confidence yet
on the exact timing. The warmest temperatures may well occur Tuesday
night or early Wednesday...offset of the normal high/low forecast
times. Temperatures could be already be on the way down by daybreak
Wednesday...or it could be 50 degrees. Other possibilities will have
to examined as confidence increases and we get more comfortable with
the timing such as the risk of flooding and the threat of
Aviation /13z Wednesday through Sunday/...
plentiful low level cloud cover is found this morning as a ribbon
of central states moisture streams across New York. MVFR ceilings from iag-
buf- roc and IFR at kjhw. VFR will linger at kart. Later this
afternoon MVFR is expected to continue at all sites but kart with
the dry air having eroded all low clouds. An Arctic front will
slide south across the region later this afternoon and evening
with a wind shift to northwest and a sharp drop in temperatures. A
low chance of snow showers is possible as the front is moisture
starved. Otherwise just a chance of lake effect snow showers south
and southeast of Lake Ontario through the overnight.
Thursday...mainly VFR but with a chance of snow Showers. Lake effect
snow likely southeast of Lake Ontario.
Friday into Sunday...mainly VFR.
a relatively tight surface pressure gradient between a storm over Quebec
and Arctic high pressure building across the Central Plains will
continue to produce gusty winds across Lake Ontario today. This
will justify keeping a Small Craft Advisory in place for the New York
nearshores of Lake Ontario.
As high pressure builds across the middle west and Ohio Valley this
afternoon into tonight winds will drop below Small Craft Advisory
criteria from east to west.
Marine...Small Craft Advisory until 9 am EST this morning for loz043-
Small Craft Advisory until 7 PM EST this evening for