Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Buffalo New York
617 am EST Thursday Nov 26 2015
strong high pressure anchored over New England will provide a dry
Thanksgiving as southerly breezes bring unseasonable warmth. The
warm weather will last through Friday morning before a cold front
crosses the region during the afternoon with showers and falling
temperatures. High pressure will bring a return to dry weather and
cooler temperatures over the weekend.
Near term /through tonight/...
strong high pressure will remain anchored over the Gulf of Maine
today and tonight and keep a complex frontal zone over the upper
Midwest at Bay for one more day. Infrared satellite imagery showing high
clouds increasing across the area early this morning with skies
mostly cloudy in western New York. There should still be some sunshine
filtering through the high clouds at daybreak across central New York
before the thicker cloud cover overspreads the region from west to
east today as middle level warm advection and moisture increase across
the lower lakes.
Expect more of the same tonight as the frontal zone remains across
the upper Great Lakes. Any warm advection driven showers along the
leading edge of the frontal zone will remain north and west of our
region overnight as dry low levels and subsidence on the western
periphery of the New England high hold strong.
The gradient between the strong high over New England and the
frontal zone over the upper Midwest will maintain a moderate wind
out of the south-southwest today and tonight. The strongest winds will be found
in downslope areas along the Lake Erie shore and near other
northward facing slopes across western New York where wind gusts may
occasionally reach 30-35 knots today and tonight. Elsewhere expect
gusts of around 20 knots.
The steady warm advection and breeze will bring temperatures to well
above average today...with highs in the upper 50s to near 60 on the
lake plains of western New York...and lower to middle 50s across the interior
southern tier and north country. Temperatures will not drop much
tonight...with lows in the lower 50s on the lake plains and middle 40s
in the coolest southern tier valleys and Lewis County. These lows
will likely occur in the evening...with temperatures slowly rising
after midnight as low level warm advection increases further.
Short term /Friday through Saturday night/...
on Friday... conflicting areas of high pressure / one warm off the
southeast coast and one cold over the northern plains / will bring an
elongated area of enhanced frontogensis from central Texas newrd
across the Ohio Valley and into the northeast. As a shortwave trough
passes north of our forecast area... this will kick the jet stream
and associated sharp temperature contrast slowly southeastward
across our forecast area Friday afternoon and evening. The result
will be a wide swath of scattered to numerous rain showers organized
roughly along the surface trough and the associated middle-level
frontogensis that lags the surface cold front. Ahead of the surface
front... however... warm southwesterly flow will allow 850 mb temperatures
to rise to near +8c with downsloping helping to push highs into the
upper 50s to lower 60s early in the day.
Expect a roughly 12 to 18 hour window for precipitation along this
slow-moving frontal passage from Friday afternoon/ evening into
early Saturday morning. With precipitation expected to continue with
the middle-level forcing behind the surface front... and overall
cooling in the column behind the front... expect there will be a
late change over to some wet snow by early Saturday morning from
north to south. Increasing cold air advection and weakening middle-
level ascent should quickly kill off the precipitation after it
mixes with or changes over to snow... thus dont expect much if any
snow accumulation or impacts. The best chance at a slushy dusting of
wet snow is in the north country... where temperatures will cool the
most and fastest behind the front and where upslope northwest flow into the
tug should help precipitation linger just a bit longer.
Saturday will see a drying/clearing trend from north to south as high
pressure builds into the region. Temperatures will be much cooler...
with highs only in the middle 30s to low 40s. Clear skies and light
winds under the high pressure by Saturday night will set the stage
for excellent radiational cooling promoting lows in the 20s.
Long term /Sunday through Wednesday/...
the attention in the extended forecast turns to the cut-off low
ejecting out of The Four Corners region across the central Continental U.S.
By Monday and eventually across the North East by mid-week.
Early in the week ahead of the approaching low... shortwave ridging
builds across the forecast area with milder return flow working
northward into western New York. Expect a slow moderating temperature
trend for Sunday through Tuesday... with highs back in the upper
40sto near 50 by Tuesday. Models are improving in placement/timing
of the ejecting low... bringing best chance of rain showers across
western New York on Tuesday along the warm front and then again along the
cold front passage. Have increased probability of precipitation to likely on Tuesday to
reflect the much improved consensus in the global models.
As the low pivots across the Great Lakes into Wednesday... the in
situ cold air and moisture with the cut-off low (850 mb temperatures to
about -6c) should be cool enough to support lake effect showers east
northeast then east of both lakes Erie and Ontario. The marginal
forecast temperatures suggest the best chances at any snow
accumulations would be over the higher terrain east of the lakes.
The progressive nature of the ejecting low should allow the flow to
quickly turn northwest by Wednesday night into Thursday... keeping
any lake effect showers from having much time to linger over the
Aviation /11z Thursday through Monday/...
middle/high clouds will thicken and slowly lower today from west to
east with VFR prevailing. Expect more of the same tonight with
periods of middle level clouds and VFR.
A moderately strong pressure gradient will remain in place today and
tonight with a gusty south-southwest wind especially in the downslope areas
along the Lake Erie shore. A 45 knot low level jet will also remain
in place today and tonight and provide at least some low level wind
shear...especially in areas where the surface winds are lighter.
Friday...VFR deteriorating to MVFR/IFR with rain showers. Rain may
end as a brief period of wet snow.
Saturday through Monday...VFR.
moderate southerlies will continue today and tonight with a strong
pressure gradient in place between high pressure over New England
and a frontal zone across the upper Midwest. The strongest winds
will be found on Lake Erie and the northeast end of Lake Ontario
where small craft advisories remain in place through Friday.
A cold front will cross the lower lakes Friday afternoon with winds
becoming north. A period of marginal Small Craft Advisory conditions
are possible along the South Shore of Lake Ontario Friday night
behind the cold front.
we are expecting highs in the upper 50s to around 60 across the
lower elevations of western New York today...about 15 degrees above
average. Here is a look at the records for today...
daily record high... 67 in 1908
Thanksgiving record high... 68 in 1896
daily record high... 67 in 1908
Thanksgiving record high... 69 in 1896
Marine...Small Craft Advisory until 4 PM EST Friday for lez040-041.
Small Craft Advisory until 4 PM EST Friday for loz045.