Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Buffalo New York
1121 PM EDT Monday Sep 22 2014
high pressure building eastward from the Central Plains will give US
one more chilly night with lows in the lower to middle 40s across
the region. Clear skies and sunshine are expected through the
rest of the week as the high pressure settles across New York state
and New England. This will provide western and north central New
York with an extended period of fine early Fall weather...along with
temperatures warming to above normal by midweek.
Near term /through Tuesday/...
mainly clear skies across western and north central New York late
this evening. Sprawling surface high pressure is centered over the
Midwest and will expand across New York overnight. Expect clear
skies through 06z or so then a large area of low/middle level clouds
observed on microwave satellite imagery will drift south across
eastern Ontario and glance areas north and east of Buffalo. This
area of cloudiness is associated with a 120kt 500mb jet streak
digging into the base of an middle level trough over Quebec. The
western southern tier should remain clear. Good radiational cooling
will occur before the clouds arrive but dewpoints holding within a
few degrees of 40 will prevent any widespread frost concerns. Patchy
southern tier valley fog will develop overnight with the clear skies
and light winds.
On Tuesday...warmer temperatures are expected under the influence of
some sunshine across western New York and a return to 850mb temperatures
near +6c to +8c. Some low/middle level clouds associated with the jet
streak will still impact north central New York. Highs will top out
around the middle 60s to around 70 except across the Tug Hill where
thicker cloud cover will keep high temperatures limited to the upper 50s..
Short term /Tuesday night through Thursday night/...
looking at the upper levels as we open the period...we open with a
Stout high amplitude ridge over the West Coast of the United States
with a split-flow pattern over the eastern half of the nation
featuring ridging over the Great Lakes and two weak troughs over the
northern plains and southeast coast respectively. Models are in
solid agreement with regards to the evolution of the large-scale
pattern over the coming week...amplifying the West Coast ridge in
response to upstream forcing and spilling it over the northern tier
of the country. This in turn cuts off the upper trough over the
plains...causing it to drift southwest to the Missouri Valley
through the end of the week. In the meantime the inverted trough
along the southeast coast slides northeast along and off the East
Coast...leaving the ridge over the Great Lakes intact and in fact
leading to the consolidation of a massive ridge encompassing the
eastern two-thirds of the nation by week's end...with the exception
of the insignificant cutoff low over the Missouri Valley.
Throughout this nation-wide pattern change western and north-central
New York will remain planted firmly underneath a shifting but
persistent dome of high pressure that will keep conditions dry at
least through the coming weekend. As the center of the high
gradually shifts east across the forecast area during the
period...temperatures will rebound back into the 70s during the day
with cool...mostly clear nights featuring lows in the 40s inland
ranging to the 50s near the lakes. The clear cool autumn nights will
allow for the formation of radiation fog in the valleys of the
Long term /Friday through Monday/...
high pressure will remain firmly in control on Saturday and
temperatures will continue to warm into the middle to upper 70s by
Saturday as the center of the high shifts off of the East
Coast...allowing for return flow to develop across the lower Great
Lakes. Amplifying ridging over the upper Midwest and northern Great
Lakes will produce troughing over eastern Canada...potentially
pushing a moisture-starved cold front to the threshold of the north
country Sunday night into Monday and consequently a slight chance of
showers has been included in the latest forecast package for the
north country and Saint Lawrence valley. Extended range forecasts
indicate a pattern shift later next week as a more progressive...but
high amplitude pattern brings a deep trough to the central U.S.
Resulting in continued warm...but possibly unsettled weather.
Aviation /03z Tuesday through Saturday/...
mainly clear skies late this evening as earlier cloud cover has
eroded. All sites should remain sky clear through 06z or so then some low
end VFR level ceilings will glance areas north and east of kbuf late
tonight through Tuesday. These clouds are associated with a jet
streak dropping south across eastern Ontario province. Clouds will
linger longest across the North County including kart. Some valley
fog will form in the southern tier but not expected to affect kjhw.
Tuesday night through Saturday...VFR...except for localized IFR in southern
tier valley fog each overnight/early morning.
winds are trending downward late this evening as high pressure
builds across the lower lakes. Small craft advisories will remain in
effect through the bulk of the night as winds and waves fall along
the South Shore of Lake Ontario.
Expansive high pressure will settle across the lower Great
Lakes on Tuesday...then will linger in place right through next
weekend. This will result in an extended period of tranquil
Marine...Small Craft Advisory until 6 am EDT Tuesday for loz043>045.
Small Craft Advisory until 2 am EDT Tuesday for loz042.