Forecast Discussion for BUF NWS Office
FXUS61 KBUF 280838

Area Forecast Discussion
National Weather Service Buffalo NY
438 AM EDT Fri Apr 28 2017

Skies will clear early this morning, allowing for a pleasant, but
cooler day with sunshine. A frontal boundary will push towards our
region Friday night, and linger over the region through the weekend,
with clouds and periodic light rain showers.


Regional radars displays a few lingering light rain showers across
the North Country this early morning, with the remainder of the
forecast area dry after last evening storms. IR satellite imagery,
and surface observations display a clearing trend to the skies
across WNY, with a surface high pressure over the Lower Ohio Valley
ridging northeastward.

For today lingering clouds will erode through the morning hours,
allowing for a sun-filled midday. Cooler and drier air aloft behind
the recently departed cold front will bring a seasonably comfortable
day in the 60s with lower humidity values. Winds will be light from
the southwest, though an occasional gust to 20 to 25 mph will be
possible. As moisture increases from the midwest this afternoon,
clouds will again begin to form and fill in across western new york.

Tonight another cold front will sag across the region, this from an
area of low pressure near James Bay. As moisture increases from the
south a few rain showers will be possible, especially south of Lake
Ontario. Lows tonight will drop back into the low to mid 50s.


A baroclinic zone will become established across the forecast area
Saturday and Sunday as we will be sitting on the northern periphery
of a ridge just off the southeastern coast. Weak waves will ripple
along this frontal boundary promoting a chance of showers through
much of the weekend. The steadiest precipitation will develop across
southern Ontario Saturday night into Sunday along an axis of warm
air advection in the mid-levels. Our region will be to the south of
this steadier rain, with more convectively driven showers across our
area. Warmer air aloft will lead to elevated instability with a few
thunderstorms are possible. However the weekend will be far from a
washout as overall forcing is weak and sporadic across our region.

Temperatures will continue to average above normal on Saturday, with
highs mainly in the 60s across the region. The surface frontal
boundary will strengthen Saturday night with increasing winds and a
sharper temperature contrast. Cold air advection will drop
temperatures to the upper 30s to lower 40s north of the I-90
corridor from Buffalo to Syracuse, with temperatures remaining
around 50 across the western Southern Tier. By Sunday the boundary
will evolve into a warm front pushing northward as a deep low
pressure system develops across the central plains. A sharp
temperature difference can be expected across the region as the warm
front moves northward with highs in the low 50s in the North Country
and along the lake Ontario shoreline to the mid to upper 70s across
the western Southern Tier.

By Monday, the anomalously deep low pressure system will track
through the upper Great Lakes while pushing a strong cold front
across the region Monday. Model consensus keeps the area mainly dry
Monday morning, with showers and thunderstorms likely Monday
afternoon and evening. Forecast wind profiles support organized
convection, but it is uncertain if instability will be ample to
support widespread severe weather. This does suggest at least a
potential for strong to severe thunderstorms along with locally
heavy rainfall. Showers and thunderstorms will taper off from west
to east late Monday night. Summer-like temperatures will also return
to the region with highs in the upper 70s to lower 80s. This is
warmer than consensus guidance which is probably too cool
considering 850mb will be around +15C.


An unseasonably deep surface low passing northwest of our region
will help usher in much cooler weather with below normal
temperatures expected. This airmass will arrive behind the cold
front on Tuesday along with a chance of some scattered showers and
gusty winds. Strong cold air advection with a source region over
central Quebec will lower 850mb temps to around zero. This will
result in highs only in the 50s on Tuesday.

Tuesday will be a windy day, with a 45-50 kt 850mb flow potentially
supporting advisory level gusts to 50 mph. Ultimately this will
depend on the track and strength of the surface low, and if there is
any sunshine to help mix these winds aloft to the surface. This
threat of gusty winds is included in the Hazardous Weather Outlook.

Winds will slacken off Tuesday night with below normal temperatures
then remaining in place Tuesday night through Wednesday and likely
Thursday with continued cold air advection as a mid-level trough
axis shifts east across our region followed by another trough
digging into the central states. Cool air instability showers will
be possible through Wednesday with the coldest core of below normal
air aloft passing by. Have continued low to slight chances of
showers for this. On Thursday medium range models show the digging
trough over the central states will kick off a surface low along the
Appalachians midweek which could lift some showers into our forecast
area from the south by Thursday. Lows Tuesday and Wednesday nights
look to dip into the upper 30s to low 40s then highs on Wednesday
and Thursday only rising into the low to mid 50s.


Showers and thunderstorms have just about cleared the TAF region
this early morning at 06Z, with activity still remaining near KART.

A few scattered MVFR clouds may pass along the southern Lake ONtario
shoreline, as well as across the SO. Tier this early morning.
Otherwise flight conditions will primarily be VFR through the end of
the TAF cycle. Winds will be light, though some occasional southwest
gusts to 20 knots or so will be possible, especially northeast of
the lakes. Tonight clouds will thicken as a frontal boundary drops
across the region. Initially these clouds will be mid level, but as
moisture increases across the So. Tier, some IFR CIGS will be
possible late tonight.

Saturday...VFR/MVFR with a chance of showers and thunderstorms.
Sunday...VFR/MVFR with a chance of showers.
Monday...MVFR to locally IFR with showers and thunderstorms likely.
Tuesday...VFR/MVFR with a chance of showers.


Behind a cold front, waves will approach 2 feet on the eastern
waters of the Great Lakes today. A frontal boundary will become
draped across the Lakes to start this weekend, though winds and
waves will remain light and minimal.

Looking a bit further out, strengthening easterly winds may bring
Small Craft Advisory conditions to the western lake waters for
Sunday. Another, stronger storm system may bring another round of
thunderstorms early next week, with gale force winds possible behind
a cold front on Tuesday.


Northeast winds will increase Saturday night and Sunday, with waves
building across western portions of Lake Ontario. This combined with
already high levels on Lake Ontario has the potential to result in
lakeshore flooding along the shoreline. The highest waves are
expected in Niagara and Orleans counties. There is still
considerably uncertainty concerning wave heights since even a slight
shift to the more easterly direction would push the highest waves to
the Canadian shoreline.


The last days of April will finish with above normal
temperatures, warm enough that it will send our climate sites
towards a top 10 warmest April on record. The degree of
anomalous warmth has been greater towards the west, where
climate site Buffalo may near the warmest April on record.
Below are the warmest Aprils on record.


Rank....Value (F).....Year


Current April average temperature through April 27th: 50.3F


Rank....Value (F).....Year


Current April average temperature through April 27th: 51.2F


Rank....Value (F).....Year


Current April average temperature through April 27th: 47.4F

Temperature records for Buffalo and Rochester begin 1871, while
Watertown`s history is a bit shorter, with temperature records
beginning in 1949.






NWS BUF Office Area Forecast Discussion