Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Binghamton New York
1248 PM EST Wednesday Mar 4 2015
cloudy but mainly dry weather is expected this afternoon, although
there may be a few rain showers over northeast Pennsylvania. Low
pressure will move northeast along a front tonight into early
Thursday bringing a good chance for another round of accumulating
snow especially for northeast Pennsylvania to the western
Catskills of New York.
Near term /until 6 PM this evening/...
1040 am update...latest satellite pics show overcast skies across
the area with some weak returns on radar over the far southeast County Warning Area.
Since temperatures in this region are in the middle 30s any lingering precipitation
here through late afternoon will be light rain showers. Latest
NAM indicates low level cold air advection will wait until early this evening
when the cold front starts dropping south through region. Temperatures
across the area will remain within a few degrees of currents
under weak cold air advection and continued overcast skies. In the northern County Warning Area
scattered flurries will be possible later this afternoon as the
7 am EST update... allowed remainder of advisory to expire as
scheduled...with precipitation becoming light and spotty. That
being said...temperatures in most places remain around
freezing...and the earlier snow-sleet-ice will still be an issue
on untreated roads in addition to patchy freezing drizzle-freezing
rain /mainly at higher elevations/. A Special Weather Statement
has been issued for these concerns along with areas of dense fog
at higher elevations.
though the main wintry mix moved through the region Tuesday
afternoon and evening...we still have had additional weak waves of
moisture riding through the brisk southwest flow. In this
event...for most of the area it appears that the cold thick layer
of several thousand feet won versus the warm wedge of above
freezing air aloft...in that after the initial burst of
snow...sleet dominated over freezing rain /it was able to refreeze
into pellets on the way down/. With the near-surface cold air
becoming shallower overnight...freezing rain became the dominant
precipitation type...but that precipitation has been spotty and
light /often freezing drizzle instead of rain/. Meanwhile
temperatures have now risen to near or even above
freezing...including 38 in Penn Yan and 36 in Hazleton.
Winter Weather Advisory was dropped earlier for Finger Lakes to
some of central New York where temperatures warmed and precipitation
became very spotty. However...a final wave of moisture is skimming
from central PA through northeast PA...to eastern southern tier-
western Catskills of New York. Where temperatures remain below
freezing...a trace to very light coating of ice can be expected
early this morning. Thus for the affected zones...the Winter
Weather Advisory remains in effect through 7 a.M. After
then...any lingering freezing rain will be spotty and light...and
only at highest elevations as temperatures continue to warm
/albeit temporary/. Also with the March sun angle and the
precipitation being very light...any remaining patchy freezing
rain-drizzle at higher elevations later this morning will have
difficulty actually accreting on surfaces.
Cold front will finish moving through this morning...with cold air
advection competing with diurnal heating through the day...the end
result being temperatures not moving much from middle morning
readings. Wave of moisture will head out by middle morning...but as
lapse rates steepen...a few showers will still pop up across the
area. The saturated layer will be fairly shallow so amounts of
rain mixing with snow today...will be very nominal.
Short term /6 PM this evening through Friday night/...
5 am update...
no rest of the weary...more accumulating snow will quickly develop
for at least some of our area tonight.
The front that drags its way through our area today...will stall
out just to our south as another wave of low pressure travels
through the midatlantic states...at the same time a secondary
Arctic front approaches. Models have consolidated fairly well
on a chunk of northeast PA to western Catskills New York receiving
another coating of snow...yet the heaviest of it will fall in
southeast to east central PA...into New Jersey and downstate New York.
Any slight jog northward to this track could bring heavier snow
into a portion of our area...so again this will have to be watched
closely. And even if things go as currently forecast...it is no
slouch as we are anticipating a good 2 to 4 inch accumulation for
the Wyoming Valley to Poconos to Sullivan County New York tonight
through Thursday morning.
This wave will feature nice jet support and a thick layer of
forced ascent which will include the dendritic growth layer.
Compared to the event that just wrapped up...being the cold side
of the frontal boundary the snow will be much drier and fluffier
which will allow it to accumulate quite well. There will be a cut
off in amounts towards the twin tiers...however in this area and
into central New York...Arctic front will drop through overnight
with resulting strong cold air advection and steep low level lapse
rates. So while actual snow amounts in twin tiers to central New York
will be limited...there may be quick bursts of snow showers
overnight into early Thursday morning. During the day...probably
also some lake effect snow showers via 290-300 flow in central New
York...lingering as flurries even into Thursday night there.
Temperatures will be mainly low to middle teens to start the day
Thursday...and will move very little due to strong cold air
advection...followed by a quick drop through the single digits
Thursday evening. Lows by Friday morning will range from 5 above
to 5 below...though northern Oneida County may get closer to 10
below. We are figuring on wind chills of 5 to 15 below Thursday
night. So indeed...yet another Arctic surge. However...this one
will not be as long lived as recent episodes. Friday will still be
on the cold side...highs upper teens to low 20s...but milder times
are en Route for the weekend. A good amount of sunshine also
expected Friday as the dry Arctic ridge of high pressure passes.
Clouds will start to increase late Friday night as a wave
approaches...so temperatures will drop very little /probably even
rise a bit towards dawn/.
Long term /Saturday through Wednesday/...
2 am update...
just minor changes following latest wpc guidance. They upped
temperatures a few degrees. Temperatures at or just below normal.
Models in reasonable agreement given the weak systems in the
northern flow. Nothing significant with the northeast U S trough
a broad upper level trough will remain over the northeast through
the extended period although temperatures will modify to near seasonal
levels late in the period. No significant storms are expected
through this period but a couple of northern stream systems will
pass through nearby southern Canada.
Late Friday night through Saturday a weak clipper type system will
pass north of the region bringing chance/slight chance probability of precipitation for snow
showers. Saturday night on back side of passing trough lake effect
snow showers will be possible under west/northwest flow. Sunday will be dry
with surface high pressure in the Ohio Valley then the next clipper will
pass north of the area on Monday with more chance/slight chance probability of precipitation for
snow showers. Monday night behind this feature a weak lake
response is possible under west-northwest flow. Dry weather is expected again
on Tuesday as surface high pressure resides in the Ohio Valley.
Aviation /18z Wednesday through Monday/...
18z Wednesday update...
Expect MVFR ceilings to dominate the taf period for kith/kbgm/kelm
with mainly dry conditions and no restrictions to visible for these sites.
For kavp, MVFR ceilings persist through tonight with an area of snow
moving in and effecting the area for the evening and overnight
period. Generally expect MVFR visible with this snow dropping at times to
IFR...especially during the latter part of this evening. Once the
snow moves out by Thursday morning, expect conditions to improve
to VFR. For ksyr/krme expect MVFR ceilings to dominate into this
evening before lifting to low end VFR with the passage of a cold
front. This front may also spark some flurries for ksyr.
Generally expect west winds 5-10 knots this afternoon becoming
more northwest this evening at 5-10 knots with the passage of an Arctic
Thursday afternoon/Thursday night...restrictions possible from lake effect
snow showers...mainly cny terminals.
Friday/Friday night...primarily VFR.
Saturday/Saturday night...restrictions possible in snow showers...
especially for cny terminals.