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Area forecast discussion 
National Weather Service Buffalo New York
622 am EDT Tuesday Sep 23 2014

Synopsis...
expansive high pressure will settle across New York state and New
England today...then will remain overhead through the upcoming
weekend. This will result in an extended period of fine early Fall
weather...along with temperatures averaging a bit above normal.

&&

Near term /through tonight/...
during the course of today...a middle and upper level jet streak
situated near the Ontario/Quebec border will slide southeastward
into the Saint Lawrence valley and Canadian Maritimes...while a
weak cold front drops across Quebec province in a similar manner.
In the process...these features will push a large attendant swath of
lower and middle level cloud cover across the north country and
portions of The Finger lakes this morning...while the remainder of
the area sees progressively lesser amounts of cloud cover with
increasing southwestward extent. Given the consequent increase in
background synoptic-scale moisture...a general westerly flow...and
a still marginally-cool airmass...cannot totally rule out a Few
Lake/ orographically-driven sprinkles across the north country this
morning...though the remainder of the area should easily remain dry.

This afternoon and tonight...the cloud cover will thin out from
southwest to northeast as the aforementioned features move away from
our region...and as sprawling high pressure and drier air
consolidates across New York state and New England. This will result
in skies once again becoming clear to mainly clear across the
majority of the region...save for some lingering partial cloud cover
across the north country and Saint Lawrence valley.

Otherwise...the only other real blemish on the forecast will be some
valley fog across the western southern tier...which will affect
that part of our area both early this morning and again later on
tonight.

As for temperatures...with 850 mb temperatures warming to between +6c and +9c
today...high temperatures should recover back to normal levels for
late September. Expect readings to largely range between the middle 60s
to lower 70s...though the higher terrain of the north country will
be cooler with highs confined to the upper 50s and lower 60s there.
Lows tonight will then range through the 40s...with the warmest
temperatures /upper 40s/ found along the lakeshores and the coolest
readings /lower 40s/ confined to far interior sections of the
southern tier and north country.

&&

Short term /Wednesday through Friday night/...
as has been promised for some time now...it will be dry and
seasonably mild during this period as impressive ridging will take a
dominant stance across the North American continent. Initially...
broad based ridging within a split flow will be situated across the
lower 48...but as we progress towards the weekend...multiple
shortwaves within a strong North Pacific jet will feed into a
deepening cut off low off the coast of the Pacific northwest. This
will amplify an already note worthy downstream ridge over the
states....leading to +3 Standard height departures across the Canadian
prairies and upper Great Lakes. The return interval for such a
commanding ridge at this of year are less frequent than once in a 30
year span.

The result of all of this will be a prolonged period of dry weather
for our region with a gradual day to day warming trend that will
send our temperatures to above normal levels.

High pressure centered near Nova Scotia on Wednesday will provide a
beautiful day across western and north central New York as sun
filled skies will send afternoon temperatures into the low to middle
70s (60s above 1800').

The fine weather will not come without a fly in the ointment though.
A weakness in the height field (ie. Disorganized middle level disturbance)
will make its way north along The Spine of Appalachians to central
Pennsylvania Wednesday night. While this feature will spread some
thick cirrus across parts of our region during the course of the
night...any shower activity and lower cloud cover should remain well
to our south.

The nebulous...disorganized middle level shortwave is then forecast to
temporarily stall on Thursday before slowly drifting east to the New
Jersey coast Thursday night. Despite the presence of this feature
though...low level ridging will continue to dominate our forecast
area and effectively shunt/deflect any shower activity off to our
southeast. This will promote continued dry weather across western
and north central New York with high and middle level cloud cover
thinning from west to east during the course of the day. 850 mb temperatures
in the vicinity of 10c will support widespread afternoon highs in the
70s.

By Friday...the split flow featuring the broad based ridge will
phase into one highly anomalous +590dm ridge centered over the
northern plains and upper Great Lakes. The aforementioned 'fly in
the ointment' shortwave will be pushed further south and east from
our region while strong surface high pressure will be centered directly
overhead. The result will be a salubrious early fall day with ample
sunshine and 850 mb temperatures of 12c boosting our maximum temperatures into the low to
middle 70s. These values will be roughly 10 degrees f above normal.

&&

Long term /Saturday through Monday/...
the medium range GFS and European model (ecmwf) based ensembles remain in strong
agreement that ridging will remain in place over the Great Lakes
region through this period. The anomalously strong ridge will be
centered over the lower Great Lakes on Saturday...then a rather
vigorous shortwave is forecast by the ensembles to drop southeast
across the Great Lakes. This will flatten the persistent ridge while
helping to push a moisture starved cold front southwards from Quebec
and southern Ontario. While this will promote an increase in cloud
cover at that time...will not carry anything higher than slight chance
probability of precipitation across the north country.

All in all...this period will feature continued dry weather with
temperatures remaining above seasonal levels.

&&

Aviation /10z Tuesday through Saturday/...
during the course of today...a middle and upper level jet streak
situated near the Ontario/Quebec border will slide southeastward
into the Saint Lawrence valley and Canadian Maritimes...while a weak
cold front drops across Quebec province in a similar manner. In the
process...these features will push a large attendant swath of lower
and middle level cloud cover across the north country and portions
of The Finger lakes this morning...while the remainder of the area
sees progressively lesser amounts of cloud cover with increasing
southwestward extent. Conditions should largely remain VFR...though
some localized MVFR ceilings will be possible across the higher terrain
of the north country...and some patchy IFR valley fog will be found
across the western southern tier through middle morning.

The remainder of the taf period will then feature a gradual
southwest-to-northeast erosion of the aforementioned cloud cover as
the the aforementioned features move away from our region...and as
surface high pressure and drier air consolidates across New York
state and New England. This will generally result in a return to
unlimited VFR conditions...though some patchy IFR valley fog should
redevelop across the western southern tier later on tonight.

Outlook...
Wednesday through Saturday...VFR...except for localized IFR in
southern tier valley fog each overnight/early morning.

&&

Marine...
winds and waves have finally fallen to just below advisory levels on
Lake Ontario...so have dropped the remaining small craft advisories
for central and eastern portions of that lake.

Otherwise...expansive high pressure will settle across the lower
Great Lakes today...then will linger in place right through next
weekend. This will result in an extended period of tranquil
conditions.

&&

Climate...
the climate prediction center has been monitoring a neutral to weak
enso event in the equatorial Pacific for several months. A suite of
their dynamic and statistical models suggest that a weak El Nino
will develop during the next couple months and persist through the
upcoming winter. This could very well have a big impact on weather
for our region.

While the phase of the enso event (el nino versus la nina) is
important to weather across western and north central New York...
local research has found a moderate to strong correlation between
the strength of the enso event and the trend in temperatures. Some
of the 'warmest' winter months (as defined by average monthly
temperature departure) have occurred during the more significant El
Nino and La Nina events...while the opposite is true for harsh
Winters.

Since 1950...18 of the top 20 'coldest' Winters across our region
have taken place during a weak to neutral enso event. This makes
sense given the teleconnection to a highly amplified jet stream
pattern across North America. Such a pattern favors frequent
intrusions of Arctic air and can be reinforced by a winter that
features ridging across Greenland. Supporting this argument is
another interesting set of statistics. Since 1950...we have had
three Winters where all five winter months (nov-march) have averaged
below normal...and five Winters where four of the five months were
below normal...all of which occurred during weak enso events.

While this is not a high confidence forecast by any means for a
second straight harsh winter...climatologically...the pattern does
favor near to below normal temperatures across the lower Great
Lakes. One has to be very careful in using just one hemispheric
pattern in making long range forecasting though. For example...a
persistent icelandic low could help to flatten the longwave pattern
over North America and thereby negate a stronger influence from the
Pacific.

&&

Buf watches/warnings/advisories...
New York...none.
Marine...none.

&&

$$

Synopsis...jjr
near term...jjr
short term...rsh
long term...rsh
aviation...jjr
marine...jjr
climate...rsh

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