Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 211805

Area Forecast Discussion
National Weather Service Buffalo NY
205 PM 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.


High pressure remains centered over James Bay this afternoon. Well
to our south, a coastal low continues to deepen as it moves off the
DelMarVa with a tight pressure gradient across the eastern Great
Lakes between these two features. High level moisture from the
coastal system is keeping thin high clouds spread across most of
western and central New York. NE low level flow 15-25 mph will
continue through the afternoon with the winds keeping temperatures
below normal. Temperatures will peak in the low to mid 30s but the
winds will make it feel only like the 20s.

The coastal low will continue to deepen while moving North off the
East Coast to southern New England tonight. Northeast winds will
back to north overnight then northwest by early Thursday morning.
Lake enhancement and upslope flow off Lake Ontario will contribute
to some low-level clouds south of the lake while low level moisture
also shifts north of the NY/PA border into Central NY overnight.
There may be just enough lift from the upslope flow to generate some
limited freezing drizzle within these low clouds over the Finger
Lakes and Genesee Valley as moisture in BUFKIT profiles is well
below the dendritic snow growth zone. Have included a slight chance
of freezing drizzle in these areas. Low clouds will also develop
east of Lake Ontario and Erie later overnight when winds become
northwest overnight. Low temperatures in the teens to mid 20s are

The deepening coastal low/Nor`easter will shift from off Cape Cod to
Nova Scotia through Thursday. Northwest winds will prevail across
western and central NY and wrap around moisture will keep cloud
cover most of the day. Perhaps Niagara county breaks into some
sunshine late in the day as the low clouds begin to erode from the
west. Expect another dry day with temperatures well below normal.
Highs again only reaching into the low to mid 30s with winds again
making it feel like teens and 20s.


Overall there is above average model agreement during the period,
with differences among model guidance limited for our area. On
Thursday night a weak mid level circulation will move from near
Georgian Bay southeastward across Lake Ontario. Once this reaches
the area late Thursday night it will result in both colder
temperatures aloft (-11C at 850mb) and deeper moisture. This should
be just cold enough for cloud tops to reach the dendritic crystal
growth zone. Thursday evening should stay dry, then expect some
light lake/upslope enhanced snow showers to develop south and east
of Lake Ontario late Thursday night and during the day Friday.

Model consensus has this mid level system to New Jersey by late
Friday, with deep layer moisture diminishing late in the day Friday.
Temperatures aloft may still support lake enhanced clouds, but
probably will not be deep enough for anything more than flurries
Friday night. Canadian high pressure will then ridge southward into
the region heading into the weekend. This will result in dry weather
Saturday, with some lingering lake enhanced clouds south of Lake

Temperatures will continue to be below normal with highs averaging
in the lower to mid 30s and lows ranging from the teens to mid 20s.
The coldest low temperatures will likely be across the Southern Tier
valleys and in 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 Sunday and 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 this afternoon will lower to MVFR or low VFR tonight
into Thursday. This will be due to low moisture from the coastal
storm sneaking northward into western and central NY and some
contribution from lake enhancement in northerly flow off Lake
Ontario. There is a slight chance of freezing drizzle south of Lake
Ontario but too low to include in the TAF at this time. Winds will
back to northwest Thursday as the coastal low shifts north off Cape
Cod toward Nova Scotia. Expect some slow improvement from MVFR to
VFR through Thursday.


Thursday night through Friday night...Mainly VFR. A
chance of Lake Effect snow south/southeast of Lake Ontario Thursday
night and Friday.
Saturday through Monday...VFR.


Low pressure off the Mid-Atlantic will move 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
the Eastern Great Lakes through the balance of today before the
moderate northerly winds remain confined to over Lake Ontario
through tonight. This will lead to advisory-worthy conditions
lingering along the south shore of Lake Ontario through Thursday

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



LONG TERM...Hitchcock
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