333 
FXUS61 KBUF 161805
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
205 PM EDT Sun Oct 16 2022

.SYNOPSIS...
A deep trough of low pressure will become established across the 
Great Lakes tonight and remain in place through most of the week, 
bringing chilly and unsettled weather to the region. The trough will 
bring a few scattered showers at times, and also bring favorable 
conditions for lake effect rain downwind of Lake Erie and Lake 
Ontario at times. Most of the precipitation will fall as rain, 
although some wet snow may mix in across higher terrain each night 
from Monday night through Wednesday night. Drier and much warmer 
weather is expected by next weekend.

&&

.NEAR TERM /THROUGH MONDAY NIGHT/...
Satellite imagery showing a few areas of mid level clouds persisting 
this afternoon, most notable across the eastern Lake Ontario region. 
Meanwhile, sunshine prevails across much of the Southern Tier and 
Genesee Valley. Highs will reach the upper 50s to lower 60s in most 
locations. A southwest wind will gust up to 30 mph northeast of Lake 
Erie.

A deep longwave trough will become established across the Great 
Lakes tonight and Monday as a strong shortwave dives into the 
deepening trough, forcing a deep closed low to develop over the 
central Great Lakes Monday. Much colder air aloft will pour into the 
Great Lakes tonight and Monday, setting the stage for an extended 
period of lake effect precipitation. 

The first half of tonight will stay dry. Overnight, DPVA and height 
falls ahead of the approaching trough will bring increasing large 
scale ascent. A surface cold front will move into Western NY late 
tonight, then move east into the eastern Lake Ontario region by 
later Monday morning. The passing cold front will bring a few light 
showers to Western NY late tonight, then much of the region Monday. 
The cold frontal showers will likely become enhanced by Lake Erie 
across the Buffalo area early Monday morning. Cold frontal and 
upslope showers will linger much of the day east of Lake Ontario as 
the cold front slows its eastward progress. 

Following the passage of the cold front, a band of lake effect rain 
will develop later Monday morning and continue through Monday night 
off Lake Erie. Monday through Monday evening boundary layer flow 
will average 220 degrees, centering the band of lake effect rain 
quite far north near Grand Island, the Tonawandas, and portions of 
Niagara County. The rain could become heavy at times and some 
thunder is possible as cold air deepens and lake induced equilibrium 
levels rise to over 20K feet. Later Monday night into Tuesday 
morning boundary layer flow will briefly veer to the WSW following 
the passage of a low level trough. This will push lake effect south 
across Buffalo and onshore along much of the Lake Erie shoreline of 
southern Erie and Chautauqua counties, spreading inland across the 
Boston Hills and Chautauqua Ridge.  

Meanwhile for Lake Ontario, boundary layer flow will remain quite 
southerly Monday and Monday night, directing most, if not all, of 
the lake effect rain into Canada.

Precipitation type will stay all rain Monday through Monday evening 
as the boundary layer stays mild, although some graupel may develop 
in heavier convective cells. Later Monday night some wet snow will 
mix in across the higher terrain of the western Southern Tier as the 
lake effect moves south and onshore. A minor coating of slush is 
possible across the higher terrain inland from Lake Erie.

Otherwise, the arrival of colder air aloft will keep highs in the 
mid to upper 40s in Western NY Monday, with low to mid 50s from the 
Genesee Valley eastward. Lows Monday night will drop into the mid to 
upper 30s in most locations, with lower 30s across the interior 
Southern Tier and Lewis County. It will be quite breezy again Monday 
and Monday night, especially northeast of Lake Erie where winds may 
gust to 35 mph.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
A deep upper level trough will linger over the Great Lakes region 
this period, with several embedded shortwaves rounding this upper 
level low. Each shortwave will oscillate bands of lake effect 
rain...that could mix with snow Tuesday night and Wednesday night as 
850 hPa temperatures become marginally cool enough for higher 
terrain snow. 

Deep synoptic moisture will be found closer to the upper level low, 
with the more defined bands of precipitation off Lake Erie. The band 
of lake effect rain could become rather heavy Tuesday over metro 
Buffalo, with a push northward across Grand Island and into Niagara 
County.

Tuesday night and into Wednesday the axis of the upper level low 
will swing across our region. This will push precipitation farther 
inland. This moisture increasing over Lake Ontario will also promote 
an increase in lake response, with lake effect precipitation 
becoming favored east of this lake Wednesday night and Thursday. The 
wind flow here will favor the northern Tug Hill, Watertown and 
through the Saint Lawrence Valley. 

Temperatures will be below normal this period, especially daytime 
highs which will be some 10 to 15 degrees below normal.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SATURDAY/...
High pressure will build across the mid-Atlantic states 
Thursday, as the deep trough across the Northeastern states 
begins to lift off to the north. A few lingering showers are 
possible Thursday night, with Friday and Saturday expected to 
be mainly dry and a bit warmer. By Saturday, highs will range 
from the upper 50s to mid 60s.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
Areas of mid level clouds will continue this afternoon through this 
evening with VFR prevailing. A cold front will then move into 
Western NY late tonight, and cross the remainder of the region 
Monday. The cold front will bring a few showers by late tonight 
across Western NY, which will become enhanced by Lake Erie. Expect 
areas of MVFR CIGS to develop over and east/northeast of Lake Erie 
late tonight and Monday morning. 

The cold front will move to the eastern Lake Ontario region later 
Monday morning through the afternoon, with a period of showers and 
MVFR CIGS. Meanwhile from the Genesee Valley westward, the showers 
associated with the cold front will largely end. Lake effect rain 
will develop over and northeast of Lake Erie with locally heavy rain 
developing. This band will likely focus just northwest of KBUF most 
of the time, but may impact KIAG more directly.

Outlook... 

Monday night through Tuesday...Scattered rain showers along with 
areas of lake effect rain/MVFR from KIAG-KBUF and mainly northwest 
of KART. The rain will mix with wet snow across the higher terrain 
both Monday and Tuesday nights.  

Wednesday and Thursday...Scattered to numerous rain showers along with 
areas of lake effect rain/MVFR east and northeast of the lakes. The 
rain will again mix with wet snow across the higher terrain Wednesday 
night.

Friday...Mainly VFR.

&&

.MARINE...
Moderate southerlies will bring Small Craft Advisory conditions to 
Lake Erie for the rest of the afternoon. Winds will then temporarily 
drop off this evening. 

A deep trough will become established across the Great Lakes Monday 
and last through much of the week, with persistent low pressure 
spinning across the province of Ontario. This will set the stage for 
an extended period of strong winds on the lower Great Lakes. Small 
Craft Advisory conditions will develop Monday morning, and then last 
through Thursday night or Friday.

Waterspouts are possible this week, although it may be too windy at 
times. Waterspouts are most common in and near bands of lake effect 
clouds when sustained winds are under about 25 knots.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory until 6 PM EDT this evening for LEZ020-
         040-041.

&&

$$

SYNOPSIS...Hitchcock
NEAR TERM...Hitchcock
SHORT TERM...Thomas
LONG TERM...Apffel/Thomas
AVIATION...Hitchcock
MARINE...Hitchcock