Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Buffalo New York
931 PM EST Wednesday Nov 25 2015
high pressure will remain across the region through Thanksgiving...
bringing mild temperatures and dry conditions. Friday will start off
mild and dry before a cold front arrives for the second half of the
day bringing rain showers and a cooling trend for the weekend.
Near term /through Thursday/...
high pressure off the New England coast will result in a southerly
return flow across the region overnight. NAM/GFS BUFKIT profiles
show the core of a south-southwest 45 knots low level jet at about 2k feet. The 00z buf
sounding was just ahead of this with weaker winds...but the VAD
wind profile shows an increase in winds which supports model
guidance. A south-southwest direction is not ideal for downsloping but
because the core of this low level jet is so low there should be partial
mixing across higher terrain and downslope regions. Expect there
will be gusts to 35 miles per hour or so in spots between 9 PM and 3 am when
the core of this low level jet passes. This will mix the boundary layer and
keep temperatures from dropping too much overnight with lows
ranging from the middle to upper 30s across interior valleys to toe
lower 40s across the lake plains. This is warmer than most
Southerly winds and abundant sunshine will boost temperatures to the
50s across the region...ranging from the lower 50s across the
southern tier and north country to the upper 50s across the lower
elevations of the lake plains. Winds will increase ahead of an
approaching cold front with a 40kt low jet forming across western New York
to The Finger lakes. It will become breezy overnight into early
Thanksgiving day with wind gusts of 30 miles per hour. Morning sunshine will
give to a filtered sunshine as high clouds precede the cold front to
Short term /Thursday night through Saturday night/...
the forecast for this time frame looks good...so no changes to this
period will be necessary this evening. The previous Disco follows
As we move into Thanksgiving night...clouds will continue to
increase across the forecast area ahead of a positively-tilted
upper level trough and surface cold front located upstream across
the upper Great Lakes. Warm air surging northwards ahead of the
front will yield a mild night across the area with lows in the
40s...with some areas near the lakeshores only bottoming out
around 50. The mild temperatures will continue into Friday as
readings climb into the middle to upper 50s with portions of the
Genesee Valley hitting the 60 degree mark before rain showers and
cooler temperatures arrive with the front late in the day.
The positively tilted upper level trough will continue to fill as it
crosses Ontario province and thus synoptic forcing is looking less
and less impressive...nonetheless frontal convergence/forcing should
still be enough to sustain rain showers as the front crosses the
forecast area from northwest to southeast from late Friday afternoon
through Friday night. With temperatures falling rapidly behind the
cold front it is possible that we may see a few snowflakes on the
back edge of the front...however with very dry air advecting in
behind the front precipitation will rapidly shut off and no
accumulations of snow are expected.
As mentioned above...temperatures will fall rapidly behind the front
as an Arctic airmass brushes the region. Consequently...temperatures
will fall into the 20s by daybreak on Saturday with highs only
limping into the upper 30s to lower 40s Saturday. High pressure
sliding across the region should keep skies sunny Saturday and the
mostly clear skies and light winds Saturday night should allow
temperatures to fall into the upper teens to middle 20s.
Long term /Sunday through Wednesday/...
the quiet weather will persist through the end of the weekend and
into the beginning of the new week as low amplitude flow aloft and
weak ridging at the surface will prevail. The cold air that brushed
across the region earlier in the weekend will retreat north into
Canada and temperatures should settle right around average with
highs in the low to middle 40s Sunday and Monday with lows in the 20s
to lower 30s Sunday night.
Readings will start to climb again Monday night as an upper level
low moving into the Great Plains spawns a surface low over the
Midwest. Milder air moving northwards ahead of this feature will
push readings back into the upper 40s to lower 50s Tuesday...and
possibly warmer. However this warmth will come at the cost of a
return to unsettled weather as the low intensifies and lifts across
the upper Great Lakes sometime Monday night or Tuesday...bringing
rain showers back to the region. Looking farther out...current
guidance is hinting at a return to lake effect snow showers by
midweek as the low lifts off to the northeast and reasonably colder
air seasoned with Pacific moisture drops across the Great Lakes.
That said...the overall pattern continues to look progressive with
no obvious blocks setting up...suggesting that any bouts of snow
will be relatively short-lived.
Aviation /03z Thursday through Monday/...
a 45 knots low level jet at around 2k feet will move across the region tonight.
Typically we look for a stronger low level jet to produce wind
shear...however in this case the strongest winds are very low
which supports low level wind shear in all taf sites for tonight. Otherwise...VFR
flight conditions will prevail through the taf period.
Friday...VFR deteriorating to MVFR with rain showers likely then
changing over and ending as some snow showers Friday night with
Saturday through Monday...VFR.
an expected increase in southerly flow tonight and Thursday has
lead to issuance of a Small Craft Advisory on the east end of Lake
Ontario and Lake Erie for tonight and Thursday.
Marine...Small Craft Advisory until 7 PM EST Thursday for lez040-041.
Small Craft Advisory until 7 PM EST Thursday for