Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 202029

Area Forecast Discussion
National Weather Service Buffalo NY
429 PM EDT Tue Mar 20 2018

High pressure centered over northern Ontario will maintain dry and
chilly weather through the end of the week. Temperatures will begin
to rise by early next week as the deep trough over the Northeast
begins to move off the east coast.


Canadian surface high pressure centered over northern Ontario will
only slowly pivot east over James Bay through Wednesday with ridging
extending south over the Great Lakes. This will keep the winter
storm at bay off to our south. The northern edge of light snow
associated with the winter storm will edge north to near but likely
remain south of the NY/PA border tonight. Skies will become mostly
cloudy due to thickening cirrus. Guidance is hinting at a lingering
northeast breeze helping some low-level Lake Effect clouds to
develop across the Niagara Frontier mainly from Orleans into Niagara
counties similar to what we saw earlier today. Lows tonight should
not be as cold as last night with the help of increased cloud cover
and a northeast breeze. Expect lows in the mid 20s on the lake
plains of Western NY and around 20 in the Southern Tier Valleys,
with low to mid teens for the North Country. Wind chills will run
between the mid single digits above zero in the cooler spots to mid
teens near the lakes.

The winter storm will shift off the Mid-Atlantic coast on Wednesday
while high pressure to our north continues to keep dry weather for
Western and North-Central NY. Partly to mostly cloudy skies, mainly
mid-high level will linger much of the day associated with the
northern edge of the winter storm. Any Lake Effect clouds in the
morning over the Niagara Frontier should breakup with daytime
heating. Winds will back to the north over the eastern Great Lakes
as the storm shifts off the coast. Expect another windy day with a
tight pressure gradient over our region with winds 15-25mph. The
northerly flow will keep temperature well below normal. Highs only
expected in the low to mid 30s but the winds will make it feel more
like upper teens to low 20s.


For the latter half of the week, low pressure will remain well to
our east, tracking from the Gulf of Maine to the Canadian Maritimes.
Meanwhile, Canadian high pressure will remain anchored south of
James Bay. This configuration will keep cool and mainly dry weather
in place across our region.

Temperatures aloft will be cold enough for some lake enhanced
cloudiness, however dry boundary layer air will limit the potential
for lake effect precipitation. On Thursday night and Friday, a
shortwave is forecast to move across the region embedded in the
western fringe of a broadly cyclonic flow aloft. This colder air
aloft may support some light lake/and or instability enhanced snow
showers south and east of Lake Ontario Thursday night and Friday.

Outside of this...the vast majority of the period will be simply dry
with below normal temperatures. High temperatures will remain the
30s each day, with nightly lows ranging from the upper teens to mid


This period is shaping up to be largely uneventful, with high
pressure initially to the west of our region, passing over the area
Sunday and Monday with sun-filled days...and then working its` way
to our east Tuesday.

Meanwhile the storm in the southern branch of the jet stream that at
one point threatened our region with snow this now
tracking well to our south across the Tennessee Valley. While clouds
from this system may brush by us Saturday, its` precipitation shield
should stay just to our south.

A shortwave in the northern branch of the jet stream will drop
across NY/NE Sunday. While this feature will pass across our region
dry it will rapidly deepen the southern storm system into a major
coastal low off the eastern shoreline. Where this happens is still
in question. A close to the shore development early next week will
likely to hold off any frontal boundaries/rain showers/warmth to our
west through at least Tuesday, while development farther out to sea
will allow for warmer air coupled with rain showers to expand across
our region Tuesday.

Temperatures below/near normal through at least Sunday...before
southerly winds behind the surface high pressure bring the prospects
for above normal warmth (mid/upper 40s) possibly by next


Surface high pressure will remain centered across northern Ontario
through tonight before pivoting to James Bay through Wednesday
while a ridge extends south over the Great Lakes. This will continue
to  provide dry weather and VFR high clouds across our region from a
winter storm over the Mid-Atlantic region. Northeast winds are
gusting to around 20-25kts. Tonight, Winds will back slightly toward
the north with some lake clouds again possible over the Niagara
Frontier including KIAG. Expect these to break mid/late morning
Wednesday with BKN high clouds leaving VFR. Winds will again be
gusty through midday to around 20-25kts.


Wednesday night through Saturday...Mainly VFR. A chance
of Lake Effect snow south/southeast of Lake Ontario Thursday night
and Friday.
Saturday night and Sunday...Mainly VFR with a chance of snow.


Low pressure will strengthen off the Mid Atlantic coast tonight into
Wednesday. This low will then move slowly northeast and offshore of
the Mid Atlantic and New England through Thursday. The pressure
gradient between this low and high pressure over northern Ontario
will continue to produce moderate north/northeast winds on Lake
Ontario and Lake Erie, leading to a several day period of Small
Craft Advisory conditions.

Additionally, a significant portion of Lake Erie from Ripley to the
Buffalo Harbor remains ice covered. With strengthening northeasterly
flow this ice pack is shifting and breaking apart which is a hazard
to anyone that might try to venture out onto the ice.


MARINE...Small Craft Advisory until 5 PM EDT Wednesday for LEZ020-040-
         Small Craft Advisory until 8 PM EDT Wednesday for
         Small Craft Advisory until 2 PM EDT Thursday for



LONG TERM...Thomas
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