Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Buffalo New York
1147 PM EST sun Nov 29 2015
high pressure will keep dry conditions and cool but seasonable
temperatures across the region through Monday night. Then low
pressure will track across the Great Lakes on Tuesday bringing above
normal temperatures and rain. A cold front will cross the region
early Wednesday which will bring temperatures back to normal with
some rain or snow showers Wednesday and Wednesday night.
Near term /through Monday/...
latest infrared satellite imagery displays plenty of low stratus
remaining locked over the region...especially over the northern
two-thirds of the County Warning Area. Expect mostly cloudy skies to persist
through the night here...with some higher clouds passing across
the southern tier.
Surface high pressure to our northeast will drift into New
England tonight which will shift winds to the east and eventually
the southeast. This will help lift any lingering cloud cover to
the north with skies expected to clear out most areas by
daybreak...or shortly thereafter. Expect lows tonight to be in the
20s...with near 30 along the immediate lakeshores.
The high across New England will continue to influence our weather
on Monday with a southeasterly flow promoting sunny skies across the
region. Temperatures will be seasonable with highs in the upper 30s
east of Lake Ontario...and in the lower 40s elsewhere.
Short term /Monday night through Wednesday night/...
Monday night...the surface high will drift east into the Gulf of
Maine while the next area of low pressure and strong middle level
closed low move into the upper Midwest. Increasing warm advection...
moisture influx and isentropic upglide in the developing southerly
flow between the two systems will bring an increase in cloud cover
from southwest to northeast overnight. A few showers may develop
across western New York and the southern tier late Monday night. Expect
early evening lows in the low to middle 30s in most areas with middle to
upper 20s across the north country.
The combination of low level warm advection and increasing clouds
will then force rising temperatures overnight. Expect temperatures
to rise above freezing several hours prior to the onset of any
showers with very little risk of any freezing rain.
The vertically stacked low will cross the upper lakes Tuesday with
DPVA and diffluent flow aloft supporting increasing large scale
ascent across our region while an occluded front brings increasing
low level convergence during the afternoon. The increasing moisture
and ascent will bring increasing coverage of showers from southwest
to northeast through the day. 850mb temperatures surge to around +10c just
ahead of the front...and this will support highs in the middle to upper
50s across western New York despite the increasing showers.
Tuesday night...the occluded front will move east across the area.
Showers during the evening will end from west to east overnight with
the passage of the frontal boundary. A well defined dry slot will
then bring a break in the rain and possibly even a period of partial
clearing overnight. Towards Wednesday morning the airmass will grow
marginally cold enough to support a Few Lake effect rain showers
northeast of the lakes.
The colder air following the occlusion will set up a marginal lake
effect pattern with limited lake effect instability. 850mb temperatures
reach about -4c Wednesday evening and -6c overnight to Thursday morning.
Will continue with the trend of lake effect rain in the lower
elevations and snow across the hills east of the lakes. First
measurable snow for Buffalo is still questionable unless there can
be dynamic cooling of the column with some heavier showers before
winds become more west/northwest late Wednesday night.
Long term /Thursday through Sunday/...
any lingering lake effect rain and snow showers southeast of the
lakes Thursday morning will end by midday as high pressure and dry
air build into the lower lakes.
On Friday...the GFS and European model (ecmwf) begin to diverge on timing with the
GFS bringing a middle level trough southward across New York and New England
Friday...while the European model (ecmwf) is slower with the trough late Friday
night. Regardless the system will be moisture starved with nothing
more than a few sprinkles or flurries at best. For now have left
both days dry with temperatures moderating to a little above average.
Both European model (ecmwf) and GFS then build high pressure across the region for
the most of Saturday and all of Sunday with clear skies and abundant
Looking farther ahead...operational guidance and ensemble means show
a high confidence forecast for above normal temperatures to continue
through the middle of December with the upstream pattern across
the Pacific and high latitudes forcing mild Pacific air to flood
east across the nation while any cold air is locked up at very
high latitudes in northern Canada. It appears there will be little
chance for measurable snow through the middle of December.
Aviation /06z Monday through Friday/...
at 06z a deck of MVFR/low end VFR ceilings remained across much of
the County Warning Area. This deck of clouds will persist through the first 3 to
9 hours of the taf cycle before drier air eventually wins out and
clearing skies return. High pressure across Quebec will slide
towards New England overnight and into Monday. This will maintain
light winds overnight that will become southeast during the day
Monday. Light winds will continue through Monday night...though
clouds will return to the region from the south...ahead of the
next storm system. This system will spread a period of rain with
MVFR ceilings/visibilities after 06z tomorrow night. There may be some IFR
ceilings/visibilities across the southern tier late Monday night.
Tuesday...rain. Mainly MVFR.
Wednesday...mainly MVFR. Rain or snow showers likely.
Thursday...mainly VFR. A chance of rain or snow showers early.
high pressure to remain in control through Monday... keeping winds
and wave minimal.
A low pressure system will then track across the Great Lakes Tuesday
into Wednesday resulting in a period of brisk southwesterly winds
ahead of the storm and west to northwest winds behind it. Small
Craft Advisory conditions will likely develop on area waters as this
weather system moves through.