Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 162317
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
617 PM EST Thu Feb 16 2017

.SYNOPSIS...
Lingering light lake effect snow showers southeast of the lakes will
diminish overnight as a ridge of high pressure builds in across the
region. High pressure will then bring fair weather and unseasonable
warmth to the area for the weekend and into early next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
A large upper-level low is departing into the Canadian maritimes
while ridging is building in across the upper Great Lakes. The cold
airmass behind the departing low pressure system continues to
support light lake effect snow showers southeast of Lake Erie and
Ontario.

Off Lake Erie...A broad area of light snow showers will continue
this evening across the western Southern Tier and portions of
Southern Erie and Wyoming counties. This may drop another dusting to
an inch in some locations. From late evening through the overnight
the snow showers will gradually taper to flurries and end as
inversion heights lower further.

Off Lake Ontario...A plume of light snow showers will continue
southeast of the lake this evening across Wayne and northern Cayuga
counties. This may produce another dusting to an inch of
accumulation this evening before slowly tapering to scattered snow
showers overnight. Farther west, a few scattered snow showers will
produce a spotty dusting from the Rochester area west to Niagara
County before ending.

East of Lake Ontario a separate area of mainly non-lake effect snow
will continue this evening, mainly due to upslope flow into the
higher terrain of the Tug Hill and western foothills of the
Adirondacks. This too may produce another dusting to an inch of
accumulation before tapering off overnight.

Otherwise for the rest of the area expect variable clouds.
Temperatures will drop into the teens in most areas, with some
single digits across the North Country.

Friday will bring fair weather to the region as the ridge axis moves
across the forecast area. Temperatures will start to recover after a
chilly start, with some mid 30s surging back into western NY in the
lee of the ridge axis, with cooler temperatures in the mid to uppers
20 linger in the North Country. Low cloud cover will start to break
out, with with an area of mid and high clouds moving across the
region ahead of a warm front moving into the central Great Lakes.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
The expansive upper level ridge currently over the central portion
of the country will be nearly overhead by Saturday morning, with
ongoing low level warm air advection continuing Friday night into
Saturday morning.  In terms of weather, the first noticeable thing
will be early overnight lows, at least over far Western NY, with a
warming trend lasting into Saturday as the warmest air at lower
levels peaks overhead.

There are some subtleties in the weather that may not be picked up by
models with this type of pattern.  From a temperature standpoint,
the recent fresh snowpack over portions of WNY will need to melt.
This will result in a delayed warmup on Saturday for portions of the
Southern Tier and Eastern Lake Ontario regions. Have dropped
temperatures a few degrees where the expected deepest snowpack is
located, but allowed some downslope warming in other regions. The
resulting high temperatures on Saturday will be highly variable.
Overall, expect 40s in currently snow covered regions while maxing
out in the low to mid 50s in portions of the Genesee Valley.

Another issue... melting snow together with the cool lakes and
abundant trapped low level moisture may result in low clouds and at
least some patchy fog late Friday night and Saturday morning.
Eventually this should mix out, but those areas that see fog may
experience lower max temperatures on Saturday than currently
forecast.

Finally, approaching the microscale, it may get a little breezy NE
of the lakes, or at least Lake Erie during the day.  This may have a
double whammy local effect on immediate Buffalo area temperature,
with possible AM fog and then cool air streaming off the lower 30F
water in the afternoon.

Saturday night and Sunday...the warmest air aloft heads east as a
surface low races east across northern Ontario Saturday and into
Quebec Saturday night.  Cooler air will seep back into the region
For Sunday. Daytime temperatures will still be well above normal,
but about 5-10 degrees below Saturday`s high temperatures.

In terms of precipitation for the weekend, look east toward the Tug
Hill for a stray shower on Sunday.  Even here, atmospheric moisture
content is confined to the lowest 5000`.  A more likely scenario is
some drizzle or low clouds in upslope regions only.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
A fast moving disturbance crossing New England will dig out a trough
off the Gulf of Maine Sunday night into Monday. This trough will
quickly shift over the North Atlantic making way for an amplified
ridge to build across the Great Lakes on Tuesday. At the surface a
dry backdoor cold front looks to press south across Central New York
on Monday ahead of Arctic High Pressure scheduled to arrive across
the Eastern Great Lakes for Monday night and Tuesday. In terms of
temperatures after a warm day Sunday, the backdoor front looks to
take about 5 degrees off surface Highs east of Lake Ontario for
Monday but only 2-3 degrees for the Finger Lakes and likely only a
degree for Western NY as 850mb temps briefly dip below 0C. A quick
rebound is in store however by Tuesday as 850mb temps rise back to
+6 or higher pushing Highs 10-15 degrees above normal. Precipitation-
wise, we continue to hold onto a slight slight chance of a snow
shower across the Western ADKs/Tug Hill Sunday night but otherwise
the incoming surface high will keep dry weather through Monday night
and perhaps even Tuesday. Have included a slight chance of showers
for later Tuesday as the surface high departs and a warm front looks
to approach from the west.

Wednesday and Thursday, 12z models generally flatten out the ridge
over the Great Lakes in response to one or more shortwave troughs
rippling across the Northern Tier of the CONUS. Consensus of the
guidance generally shows a few weak surface lows and associated weak
frontal boundaries that run near our forecast area mid-week which
could bring some precipitation but confidence is very low and thus
only included slight chance pops. Confidence for a continuation of
above normal temps is higher as 850mb temps looks to remain close to
10C above mid-Feb means. Have therefore kept surface temperatures
above normal for mid-week with highs close to 50 across WNY and into
the 40s east of Lake Ontario. Overnight lows will dip to the mid-30s
across WNY and down to around freezing for the North Country.

&&

.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
Light lake effect snow showers will continue to produce MVFR/IFR
conditions southeast of the lakes this evening before slowly
tapering off overnight as high pressure builds into the area.
Outside of the lake effect snow showers, areas of MVFR CIGS will
continue overnight with lake effect clouds streaming off the lakes.
These lower clouds will slowly scatter out later tonight and Friday
morning with a return to VFR in most locations. Mid/high clouds will
then increase from west to east on Friday ahead of a warm front
moving into the central Great Lakes.

Outlook...

Saturday... Patchy morning fog in WNY with local IFR, otherwise VFR.
Sunday and Monday...VFR.
Tuesday...Chance showers. Mainly VFR with MVFR possible.

&&

.MARINE...
Small craft worthy northwesterly winds will continue on the lower
Great Lakes through this evening. Winds will slowly weaken overnight
into Friday morning as high pressure builds across the lakes. Light
winds and wave action are expected for the weekend as high pressure
takes hold and keeps fair weather in place.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory until 10 PM EST this evening for LEZ040-
         041.
         Small Craft Advisory until 7 AM EST Friday for
         LOZ042>045.

&&

$$

SYNOPSIS...CHURCH/HITCHCOCK
NEAR TERM...CHURCH/HITCHCOCK
SHORT TERM...ZAFF
LONG TERM...SMITH
AVIATION...HITCHCOCK
MARINE...CHURCH


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