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000
FXUS61 KBUF 231042
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
642 AM EDT Tue Oct 23 2018

.SYNOPSIS...
A cold front will cross the region today and showers with possible
thunderstorms are expected. Some showers and thunderstorms will
bring gusty winds and small hail. Cold air will spread across the
region behind the front and lake effect rain and snow showers will
continue into the middle of the week. High pressure should bring dry
weather Thursday and Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
A large mid-level trough resides across the northeastern tier of the
CONUS this morning. A strong shortwave trough depicted in the GOES-
16 water vapor imagery is over S MI/N OH and will track across
the eastern Great Lakes today. Low pressure will also track
across Lake Ontario and into New England today.

A cold front is stretched from Georgian Bay to central Ohio
this morning. A disorganized band of showers is currently
ahead of the frontal boundary and will continue to move east
across Western NY this morning. Current hi-res guidance depicts
the front to move through the Niagara Frontier by 16z and the
Genesee Valley and Western Finger Lakes region by 20z. Cold air
aloft will promote steepening lapse rates behind the front and
scattered showers are expected in its wake. There is a chance of
thunderstorms that may produce small hail/graupel late this
morning into the afternoon. Winds will become west- northwest
behind the front ushering in much colder air. Gusty winds are
possible in any thunderstorms that develop. 850Ts will be
falling throughout the day and lake effect showers are expected
to develop shortly after the front goes through. As low pressure
tracks from Georgian Bay into Northern NY today, showers will
likely stay south of the North Country through the afternoon.

The mid-level trough will track into northern New England tonight.
Northwest flow will reside across the eastern Great Lakes. 850Ts
will continue to fall into Wednesday morning. Synoptic forcing and
deep moisture will continue across Lake Ontario overnight and lake
effect rain and snow showers will persist. A weak shortwave trough
will likely track across eastern Lake Ontario and the North Country
late tonight. This will lead to showers spreading across much of the
forecast area by Wednesday morning. Off Lake Erie...moisture
will diminish as large scale ascent tracks east overnight. Lake
effect rain and snow showers will become scattered across the
Western Southern Tier overnight. Temperatures will fall into the
mid to upper 30s to low 30s at higher elevations. Snowfall
accumulations of up to an inch are possible across the higher
elevations of the Western Southern Tier and Tug Hill Plateau
through tonight.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
An area of high pressure will be building east from the upper
Midwest/western Great Lakes on Wednesday, as low pressure departs
eastward into the Canadian Maritimes. The coverage of showers will
lessen during the day as moisture depth decreases, and be mainly
confined to areas southeast of Lake Ontario from Rochester to
Fulton, reaching into the Finger Lakes. Northerly upslope flow
could also bring some lake enhancement to the western Southern
Tier. Thermal profiles suggesting that during the morning rain
or a rain/snow mix will be favored at lower elevations with
predominantly all snow at higher elevations, especially across
the western Southern Tier. Accumulation will be minimal,
generally an inch or less with the greatest accumulations across
the higher terrain. It will be a chilly day with high
temperatures in the lower to mid 40s on the lake plains and
upper 30s across higher terrain. Brisk northwest winds will push
wind chills downs into the 30s and upper 20s.

High pressure will continue to build east with the ridge axis just
upstream by Thursday morning. Persistent northwest flow ahead of the
approaching ridge will maintain scattered lake effect rain/snow
showers. This activity should be diminishing in coverage and
intensity as inversion heights decrease. Lows will be in the lower
30s on the lake plains, and mid to upper 20s across the Southern
Tier and east of Lake Ontario.

High pressure will become situated overhead Thursday and Thursday
night. This will end any lingering lake effect early Thursday,
although it may take a bit longer to get rid of the cloud cover
trapped underneath the inversion. Do have the expectation for at
least partial clearing for most areas by afternoon. Still quite
chilly with high temperatures in the lower 40s on the lake plains
and mid to upper 30s across higher terrain.

It continues to look like a decent radiational cooling conditions
Thursday night as much of the guidance suite suggests partly
cloudy/mainly clear skies and light/variable winds. Expect lows to
drop into the 20s areawide with the possible exception of the
immediate lakeshores.

Friday should start out with partly/mostly sunny skies, with
southern tier valley fog, gradually featuring more cloud cover
throughout the day. Weak warm air advection should support a
somewhat milder day with temperatures topping out in the lower
to mid 40s. While a select few guidance members try to squeeze
out a few showers across parts of western New York late Friday
afternoon, the expectation is that lingering deep layer dry air
from departing high pressure will win out as higher chances for
showers will hold off until Friday night.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
The forecast for this coming weekend remains very interesting as it
is hinged upon the evolution of the remnants of the preset Major
Hurricane Willa in the eastern Pacific Ocean basin. After landfall
on the Pacific coast of Mexico later Tuesday, the latest model
consensus from 22/12z tracks the remnants east across Mexico and the
Gulf Coast mid to late week. The remnants are then forecast to
transfer to the Carolina coast Friday or Friday night before lifting
north the along the East Coast as a deepening extratropical cyclone
Saturday and Sunday. This system has the potenial to draw Atlantic
moisture westward with chances of rain and snow possible across
western and north-central New York arriving as early as early
Saturday morning then remaining in the forecast through the weekend
into Monday. The 12z ECWMF and GEM are in decent agreement with the
arrival of moisture across New York through Saturday while the GFS
continues to keep the system to our east with a potential for little
to no precipitation across our forecast area. As the coastal
storm/Nor`easter exits across the Canadian Maritimes Sunday, the
core of the parent mid-level trough is forecast to pivot across the
Great Lakes bringing additional chances for precipitation into
Monday.

Temps are forecast to run 5-10 degrees below normal across western
and north-central New York Saturday through Monday as the amplified
mid-level trough circulates cool Canadian air south across the Great
Lakes. Temps will likely range from the 40s during the daytime to
30s overnight. The cooler overnight temps will bring a risk for rain
to mix with or change over to wet snow especially across the higher
terrain. Those with outdoor plans this coming weekend should
continue to monitor forecast updates.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
A cold front will track across Western NY by early afternoon.
Showers are likely ahead of the cold front this morning and
behind it this afternoon. Cold air aloft will result in
steepening lapse rates through the day and showers and isolated
thunderstorms may produce small hail or graupel. Gusty winds are
also possible in any showers. A surface low will track across
KART today which will keep them shower- free until this evening.

Lake effect showers will gradually develop on NW flow this afternoon
with increasing MVFR and some IFR CIGS after 18Z. Tuesday night will
have lake effect rain/snow showers southeast of both lakes with
MVFR/IFR.

Outlook...

Wednesday...lake effect -SHRASN SE of the lakes with VFR/MVFR.
Thursday and Friday...VFR.
Saturday...VFR...possibly MVFR with showers.

&&

.MARINE...
Light winds and waves will persist early this morning. A cold front
will track across Lake Erie this morning and move across Lake
Ontario by early afternoon. Winds and waves will increase ahead of
the front. SW flow will be come westerly, then northwesterly
increasing behind the front. Small Craft Advisories are in effect
along Lake Erie through Wednesday and through Thursday afternoon for
the southern shore of Lake Ontario. High pressure will bring lighter
winds for Thursday and Friday.

Waterspouts of likely behind a cold front today and tonight as lake
induced equilibrium levels rise to greater than 15K feet as the next
pool of cold air aloft crosses the eastern Great Lakes. Showers and
isolated thunderstorms will likely bring gusty winds today.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory until 4 PM EDT Wednesday for LEZ040-041.
         Small Craft Advisory from 2 PM this afternoon to 2 PM
         EDT Thursday for LOZ042-043.
         Small Craft Advisory from 8 PM this evening to 2 PM EDT
         Thursday for LOZ044.

&&

$$

SYNOPSIS...HSK
NEAR TERM...HSK
SHORT TERM...TMA
LONG TERM...Smith
AVIATION...HSK
MARINE...HSK