Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 201849

Area Forecast Discussion
National Weather Service Buffalo NY
149 PM EST Mon Feb 20 2017

High pressure will continue to provide our region with fair weather
through midday Tuesday. A weak front will then cross the area later
Tuesday and Tuesday night with a period of rain showers. Mainly dry
weather will then return for Wednesday and Thursday before low
pressure moves into the Great Lakes Friday with the next period of
rain. Temperatures will remain well above average through the week
before colder air arrives next weekend.


Surface analysis this afternoon shows high pressure centered over
western Quebec extending south along the eastern third of the CONUS.
Visible satellite imagery shows clear sunny skies across NY.
Temperatures today are running cooler than what we saw over this
past weekend do to some cooler and drier air which has arrived
behind a backdoor cold front. Highs today will range from the mid to
upper 40s across the western Southern Tier and Niagara Frontier but
cooler from Rochester eastward with highs only running in the mid
30s to around 40.

Tonight the center of the surface high will shift further toward the
East Coast while the axis of mid-level ridging shifts across western
NY. Expect mainly clear skies through the overnight with only a few
thin high clouds perhaps drifting overhead. Dry air in place with
dewpoints in the teens and 20s will support another cool night with
decent radiational cooling. Far western NY should dip down to around
the freezing mark while the Genesee Valley and Finger Lakes see 20s
and reading dip into the teens east of Lake Ontario closer to the
center of the surface high.

The mid-level ridge and surface high will shift off the East Coast
on Tuesday making way for a weak cold front to work its way toward
western NY. Consensus of latest guidance holds off any showers ahead
of the front until the afternoon hours for western NY leaving the
morning dry. Increasing southerly flow ahead of the front should
help boost temperatures into the 50s again for much of western NY
and 40s for central NY despite increasing cloud cover ahead of the


There will be neutral to warm air advection behind the front
Tuesday night and into Wednesday. Lingering low level moisture
will likely bring a period of low clouds and fog to the region,
especially over SW NYS, and east of Lake Ontario where a
snowpack remains.

A low level inversion Wednesday morning may remain low clouds
through the day, but as winds become southwesterly, and increase
through the day clouds will break for some afternoon sunshine.

Weak high pressure following the cold front should bring fair
weather Wednesday and Wednesday night to our area.

Temperatures Tuesday ahead of the weak cold front will climb into
the 50s across WNY, with mid to upper 40s east of Lake Ontario. The
little cold air behind the cold front Wednesday will again continue
the above normal temperatures, with highs pushing into the 50s,
possibly reaching the lower 60s across the Genesee Valley.


During this period a blocked flow will persist across the northern
hemisphere...with a Rex Block remaining anchored between Alaska and
the Hawaiian Islands. Across the CONUS...this will favor large-scale
troughing across the western half of the country and broad/flat
downstream ridging over the east...which for our region will translate
into temperatures remaining above typical late winter averages. While
the overall pattern may break down a little early on with the trough
temporarily broadening across the country and consequently leading to
an incursion of seasonably colder air into our region next weekend...
this should be short lived as the various guidance packages still
suggest that the mean trough will become re-established over the west
by the end of next weekend or early next week.

In terms of the day to day weather...the upper level pattern described
above will be very conducive for `cutter` type storms to make their
way from the high plains to the Upper Great Lakes. This storm track
will keep the storm systems to our west...further enhancing the mild
weather with periodic injections of warmth from the GOMEX. During the
extended portion of the forecast...this will be the case Friday and
Friday night when a sub 990mb low will direct some late winter sub
tropical warmth (H85 temps 10 to 12c) across the Lower Great Lakes.
Following the passage of this low and its trailing cold front sometime
on Saturday...the aforementioned colder air will then filter across
our region through the remainder of the weekend...resulting in our
temperatures pulling back closer to normal...but still remaining a
bit above average overall.

With respect to precipitation potential...the cutter system referenced
above should bring general shower chances to our region Friday right
through Saturday...with these appearing most likely to peak sometime
during Friday night...when PoPs have been bumped up to the low likely
range. After that...drier weather should return for the rest of the
period...with any potential lake response east of the lakes likely
remaining greatly limited in scope by the dryness and marginally cold
nature of the incoming colder airmass.


VFR in place this afternoon under SKC with high pressure overhead.
Northeasterly winds this afternoon will veer around to southerly
tonight into Tuesday as the high pressure shifts off the east coast
and a weak cold front approaches. Any -SHRA will hold off until just
after 18z Tuesday with VFR cigs.

Tuesday night...Rain showers with areas of MVFR
Wednesday...Mainly VFR.
Thursday through Saturday...Mainly VFR with several chances of
rain showers and associated MVFR.


Northeast flow in place this afternoon with some mild chop along the
south shores of Lake Ontario, but winds and waves should remain
small craft advisory criteria. While winds will gradually freshen
with a continued veering flow tonight, the flow will be offshore and
this will limit the risk for small craft advisory conditions. A weak
cold front will cross the lakes later Tuesday with some rain
showers. The lower lakes will be between systems on Wednesday, with
a light southwesterly flow expected.





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