Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 211459

Area Forecast Discussion
National Weather Service Buffalo NY
1059 AM EDT Wed Mar 21 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.


A dry airmass will persist across the eastern Great Lakes as high
pressure remains nearly stationary over James Bay. A closed mid-
level low is moving eastward across the Mid-Atlantic region today
which will deepen a coastal low as it moves northward towards
Southern New England. High level moisture from this system will keep
thin high clouds spread across most of western and central New York.

NE low level flow will continue over western and central NY as the
surface low pressure strengthens off the Mid-Atlantic coast with the
winds keeping temperatures below normal. The tight pressure gradient
is resulting in another breezy day with winds 15-25mph. High
temperatures will reach into the low to mid 30s but the winds will
make it feel only like the 20s.

The coastal low will move along and south of the southern New
England coast tonight. Northeast winds will become northwest by
early Thursday morning. Lake enhancement will likely produce some
low-level clouds across Western NY south of Lake Ontario overnight.
Scattered flurries are possible mainly across the Lake Plains and
western Finger Lakes. Elsewhere, mid-high level clouds from the
coastal low will continue to move overhead. Low temperatures in the
teens to mid 20s are expected.


The Nor`Easter will stall temporarily on Thursday near the southern
tip of Nova Scotia before moving northeast across the Canadian
Maritimes Thursday night and Friday. This will maintain a northwest
flow of cold air across the Great Lakes region through the end of
the week.

On Thursday low level moisture will be very shallow, and the
dendritic crystal growth zone will remain well separated from the
cloud bearing layer. This should prevent any light flurries or snow
showers. The moisture depth does appear sufficient to support lake
effect and upslope clouds. Late Thursday night and Friday a weak mid
level circulation will move from near Georgian Bay southeastward
across Lake Ontario. This feature will bring weak ascent, and more
importantly deeper moisture to our region. Lake induced equilibrium
levels will rise to around 6K feet, with some chance of the top of
the lake effect clouds reaching the dendritic crystal growth zone.
This may produce a few flurries or light snow showers across the
region from late Thursday night through Friday evening, supported by
a weak lake response and upslope flow. Any leftover snow showers east
of Lake Ontario Friday evening will end by Saturday morning as the
deeper moisture pulls away.

Highs will continue to run close to 10F below normal, with highs
Thursday and Friday in the mid 30s on the lake plains and upper 20s
to around 30 across the high terrain. The added cloud cover will
help keep lows up to some extent, with 20s in most areas and teens
relegated to the colder Southern Tier valleys and Lewis County.


The tranquil weather will continue through the long term period,
with cold temperatures over the weekend finally yielding to some
warming by early next week. The deep longwave trough which has
dominated the Great Lakes and New England for the entire month will
be forced off the east coast by upstream pattern changes across
North America and the eastern Pacific.

Dry weather will continue Saturday through Monday as high pressure
slowly drifts east across Quebec, with a ridge extending down into
the eastern Great Lakes. Temperatures will remain on the cool side
of normal over the weekend, with highs still in the 30s.

By early next week warm advection and height rises will spread east
across the Ohio Valley and Great Lakes, with a stronger push of
warmer air timed for Tuesday in the latest GFS and ECMWF runs. If
this verifies, highs in the 50s may be a real possibility by
Tuesday. Along with the warm-up will come increasing chances of a
few showers by later Tuesday as a system moves into the Ohio Valley
and Great Lakes. Latest 00Z models suggest the greater chance of
rain will hold off until Tuesday night.


VFR conditions will continue through tonight with thin high clouds
originating from a coastal low off the Mid-Atlantic coast. A
pressure gradient between high pressure over James Bay and the
coastal low will maintain northeasterly flow today 10-20kts. Wind
will become N around 10kts tonight. Besides a slight chance of
scattered lake effect snow flurries late tonight south of Lake
Ontario, dry conditions expected into Thursday morning.


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


Low pressure will strengthen off the Mid Atlantic coast this
afternoon before moving slowly northeastward offshore of the New
England coast tonight and Thursday. The pressure gradient between
this low and high pressure over northern Ontario will continue to
produce moderate northeasterly/northerly winds on Lake Ontario and
Lake Erie, leading to advisory-worthy conditions into tonight along
the south shores of both lakes.

Additionally...the persistent northeasterly flow continues to displace
and/or break up the existing ice cover over eastern Lake Erie...which
remains a hazard to anyone attempting to venture out onto the ice.


MARINE...Small Craft Advisory until 5 PM EDT this afternoon for LEZ040-
         Small Craft Advisory until 2 PM EDT Thursday for



SHORT TERM...Hitchcock
LONG TERM...Hitchcock
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