Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Buffalo New York
343 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 will move from New England to the offshore waters of
the New England coast by this evening... increasing the warmer
southerly return flow across the region. 850 mb temperatures will
rise to around +4 to +6c by this afternoon... and when combined with
some light downslope flow should amount to daytime highs in the middle
40s to the lower 50s. The downslope flow will further help to scour
out any remaining low-level moisture and morning clouds resulting in
a sunny day. Temperatures wont fall much overnight with continuing
weak warm air advection and southerly downslope flow keeping lows
in the middle to upper 30s... and setting the stage for a mild
Thanksgiving ahead on Thursday.
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/...
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 /21z Wednesday through Monday/...
expect a pleasant VFR flying day ahead today across the taf sites.
Low level wind shear is expected to develop tonight as a 40+ knots
low level jet shifts over western and central New York ahead of a
slowly approaching cold front. VFR flight conditions will prevail
through the taf period.
Thursday...VFR. Low level wind shear tonight into Thursday morning.
Friday...VFR deteriorating to MVFR with rain showers likely then
changing over and ending as some snow showers Friday night with IFR
Saturday through Monday...VFR.
high pressure and light winds will bring fair conditions on the
lakes this evening. An expected increase in southerly flow Wednesday
night and Thursday has lead to issuance of a Small Craft Advisory on
the east end of Lake Ontario and Lake Erie Wednesday night and
Marine...Small Craft Advisory from 10 PM this evening to 7 PM EST
Thursday for lez040-041.
Small Craft Advisory from 7 PM this evening to 7 PM
EST Thursday for loz045.