Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 160002

Area Forecast Discussion
National Weather Service Buffalo NY
802 PM EDT Fri Oct 15 2021

A deepening area of low pressure will pass to our west tonight,
shoving a cold front across the region and bringing showers and
thunderstorms with it. Following the cold front, breezy
conditions will remain through the weekend while also bands of
lake effect rain oscillate to the east and southeast of the
Lakes through early next week.


...Strong Thunderstorms Possible This Evening...

Low pressure centered over western Ohio will move NNE, allowing a
warm front to surge northward. Strong to severe thunderstorms will
be possible across the IAG Frontier and Genesee valley. Organized
rotating cells will be possible, which would bring the entire gamut
of severe weather into the range of possibilities...damaging wind
gusts, and even a tornado or two. This has been covered by a slight
risk from SPC, which seems warranted given the atmospheric
conditions, even with instability likely to be on the lower end
of things.

As the warm front continues to surge northward with the approach
of low pressure to the west of the area, atmospheric conditions
will become less favorable once it moves into the North Country,
so severe weather will be less likely there. Then, as the low
moves farther along, a cold front will start to bear down on the
area by late tonight.

Behind activity this evening, a lull looks to be at hand as we
wait for the trailing cold front to cruise toward the area. This
eventually happens overnight toward morning. Forcing along the
front is solid, and shear is also impressive, however
instability will not be. A rumble or two of thunder will be
possible, but the forcing along the front may be enough to mix
out some of the momentum to the ground in the shallow
instability along the front. This may yield another short
window gusty winds overnight toward morning. The best moisture
surge along the cold front does look to wait until Saturday, so
mentions of heavy rain with the cold frontal passage have been
pulled from the forecast until the better moisture surge arrives
on Saturday afternoon over the eastern half of the area.


A strong cold front will exit to the east Saturday afternoon while
cold air advection moves into western and central NY. The associated
upper level trough will become negatively tilted as the trough axis
swings across the region Saturday afternoon-Saturday evening. Strong
forcing with diffulent flow aloft will result in showers across the
region with the chance for thunderstorms east of the Genesee Valley.
High PWATS will be diminishing from west to east across the region
as the front moves to the east. A few strong storms are possible
from interior Southern Tier, Finger Lakes and into the North Country
with a threat of gusty winds and heavy rain. High temperatures will
be met Saturday morning across western NY with highs in the low 60s.
A longer period of warming will occur east of the Genesee Valley
into Saturday afternoon where highs in the mid to upper 60s are

Temperatures will fall Saturday afternoon-Saturday night under
westerly flow. Boundary layer mixing will likely continue Saturday
night with gusty, westerly winds. Temperatures at 850mb will be
falling to the low single digits (Celsius) by Sunday morning. A lake
response will kick in Saturday night as delta T`s are easily met
with Lake Erie temperatures in the 15-19 C and Lake Ontario
temperature in the 12-16C. An upper level trough will be overhead
Saturday night through Sunday night. Synoptic moisture combined with
a cold airmass moving over the warm Lakes will result in lake
enhanced rain showers across the region. Scattered rain showers are
expected across the region Saturday night into Sunday morning with
lake enhanced bands east-southeast of the Lakes. Winds become west-
northwest Sunday afternoon as a cold front moves through the region.
Temperatures at 850mb will further fall to the minus low single
digits. This will increase the coverage of showers across the entire
region with enhancement southeast of the Lakes. The trough will move
into New England Sunday night and synoptic moisture will diminish
overnight. Lake effect rain showers will continue southeast of the
Lakes into Monday.

A shift in temperatures expected through Monday night as
temperatures fall below normal. Highs will rise into the mid 50s
Sunday and Monday with lows in the 40s Saturday night and Sunday
night. Breezy conditions expected Sunday and Monday with gusts up to
25-30 mph.


Strong ridge of high pressure still looks to influence our weather
for the Tuesday/Wednesday timeframe, however the large upper trough
looks to possibly get hung up over New England for an additional 12-
18 hours as ridge to the west over the upper Great Lakes tries to
nudge it eastward. That said, our area should be under the
anticyclonic umbrella of the eastern side of the ridge, so still
expecting dry weather for at least Tuesday through Wednesday. Caveat
being that if this trend continues, small chance for a shower could
creep back in the forecast across areas east of Lake Ontario toward
the start the period.

The other side of this coin is that this would possibly lead to a
delay in the next system that`s due to impact our area by the same
amount of hours. This would possibly hold off the next chance of
showers associated with the next storm system until sometime
Thursday versus Wednesday night. Will continue with generally Chc
PoPs for the second half of the period at this time. However, if
this trend continues, may need to trend back on PoPs for Wednesday
night and Thursday with future packages.

Temperatures will be a bit above average for the majority of the
period, before trending back to near normal for the end of the work


VFR cigs will deteriorate to IFR to MVFR levels tonight as a warm
front will gradually push northward through the region. While there
will be some showers and thunderstorms this evening...the activity
will become more widespread late tonight and early Saturday morning
when a strong cold front will near from the west.

Widespread showers with heavy rain will accompany IFR to MVFR cigs
Saturday morning when the front will cross the region. Cigs will
grudgingly improve to VFR levels late in the day.

VFR to MVFR cigs are forecast for Saturday night as lake effect rain
showers will set up east/southeast of both lakes. This activity
could include some thunder and lightning at KJHW and KROC.


Sunday...VFR/MVFR with a chance of lake effect rain showers
east of the lakes. Breezy.
Monday...MVFR in lake effect rain showers southeast of the Lakes,
otherwise VFR.
Tuesday and Wednesday...VFR.


Southwest wind tonight ahead of a strong cold front. While
winds may occasionally reach small craft criteria on Lake Erie
ahead of the front, the long duration small craft conditions
will be behind the cold front Saturday and into the beginning of
next week. Winds will average from a WNW direction with 15 to
25 knots.


MARINE...Small Craft Advisory from 10 AM Saturday to 6 AM EDT Tuesday
         for LEZ040-041.
         Small Craft Advisory from 1 PM Saturday to 8 AM EDT
         Tuesday for LOZ043>045.
         Small Craft Advisory from 10 AM Saturday to 6 AM EDT
         Tuesday for LOZ042.



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