Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Binghamton New York
156 PM EST Friday Nov 28 2014
a westerly flow of cold air will develop lake effect snow
today...with the heaviest accumulation over the northern Finger
Lakes into the western Mohawk Valley. Elsewhere...just some
scattered snow showers are expected. A warm front approaching the
area from the Ohio Valley will bring additional snow showers on
Near term /until 6 PM this evening/...
1 PM update: upgraded the lake effect Snow Advisory to a warning
over northern Oneida County based on latest radar and reports.
Previous discussion: shrp upper WV over western New York at this time moving slowly
east. Some light lake enhanced snow showers along and ahead of the upper
trough moving into the forecast area at this time. As the WV pulls out...a well
aligned westerly flow develops averaging around 280 degrees. With rsnbl
instability off the lake and a fairly hi inversion...single band le
event is expeceted to develop off Ontario into the northern zones. Mvmt of the
upper WV has been a bit slower than expeceted so the band has not yet
developed...but this in turn shd allow it to linger longer into the
evening before drier air...lowered inversion...and strengthening ll shear
weakens the band. Have gone ahead and extended the advisory through 00z to
cover the expeceted band timing.
Snowfall amts have been edged up a bit...and of course extended into
the evening. Total amts not all that much more since the onset is
delayed...and band shd continue to drift north...especially near the end of
the advisory period.
Short term /6 PM this evening through Monday/...
several factors bring an end to the le band in the forecast area
including shear...drier air...and a more southwesterly flow developing ahead of
the next WV. Overnight hours shd gnrly be dry other than the chance of a
bit of Erie le and weak overrunning precipitation into Sat morning.
Gnrly overcast Sat as the warm air advection continues and still the chance of some light
precipitation...especially over the northern and western zones with stronger uvm and some
lake moisture available. Gnrl west-southwest flow with pockets of middle level moisture
and lift Sat night into sun. This will lead to overcast skies and perhaps
some light precipitation. Temperatures on sun hi enough for for any precipitation to be liquid.
Temperatures sun will rise to to above normal...but guidance may not be fully
accounting for the snow cover...especially over the eastern zones so have gone
slightly cooler in the grids.
Long term /Monday night through Friday/...
medium range models are in fair agreement through the early part
of the extended forecast then by middle week the European model (ecmwf)/GFS are
significantly different. Followed wpc guidance which leaned heavily
on the European model (ecmwf).
Period begins with surface cold front well to our east with strong
Canadian high pressure building over region. Will continue with chance
probability of precipitation for lake effect snow showers over northern County Warning Area but very dry
airmass and subsidence will end activity by late night. Tuesday
will be dry and seasonal with surface high pressure moving to northern New
England. Tuesday night and Wed, surface low pressure will track through
eastern Canada pushing a warm/cold front through the area. Will
carry chance probability of precipitation through the area with p-type being primarily snow
showers. Wednesday night through Friday, looks primarily dry with
surface high pressure in the Ohio Valley. Low confidence forecast at this
point due to divergent model solutions.
Temperatures during the period will be slightly below seasonal normals.
Aviation /19z Friday through Wednesday/...
a band of lake effect snow showers will persist over the krme/ksyr
terminals through early evening. At krme, MVFR snow showers with
occasional IFR/below alt min snow showers will occur through 02z.
At ksyr, flurries with occasional IFR snow showers will occur
through 22z. Rest of terminals will have strato cumulus around 4k feet
through early evening. Westerly flow will weaken then shift to
the southeast overnight as weak warm air advection occurs. As the low VFR clouds
scatter out this evening a middle deck will develop followed by ceilings
around 4k feet toward daybreak.
Winds northwest at 10 knots gusting to 20 knots becoming light and
variable this evening then southeast around 5-10 knots on Saturday.
Sat...possible restrictions from scattered -shsn.
Sun...restrictions possible from -shra.
Monday...restrictions possible from -shra/shsn.
Wednesday...restrictions possible from -shra/shsn.
New York...Lake effect Snow Advisory until midnight EST tonight for
Lake effect snow warning until midnight EST tonight for nyz009.