Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 061947

Area Forecast Discussion
National Weather Service Buffalo NY
247 PM EST Sat Mar 6 2021

Wintry weather will continue during this weekend with some snow
showers possible through Sunday morning. A warm front may bring
a few snow showers east of Lake Ontario Monday night, while
also signaling the start of a significant warming trend. Spring
like temperatures are expected during the middle of the week.


Temperatures aloft at 850 hPa are in the negative teens which is
plenty cold enough to support lake effect snow, however synoptic
scale moisture is limited. Contrary to most mesoscale guidance radar
shows more lake enhanced snow showers off Lake Erie instead of
Lake Ontario. This is probably due to the moisture contribution
from Lake Huron which is displayed nicely by IR satellite
imagery. A shortwave diving southward across eastern Ontario
province should provide a little more moisture for Lake Ontario
to work with, but with higher March sun angles at work snow
accumulations today should be minimal...maybe an inch or two in
most persistent snows but just flurries for most locations.

Tonight inversion heights will lower, and moisture will thin more.
Though accumulation factors improve tonight with the setting sun,
lake snows will become lighter with an inch or less accumulation
southeast of Lake Ontario and east of Lake Erie. Low temperatures
will range from the teens south of Lake Ontario to the single digits
across the North Country where there will be some clearing tonight.

Surface high pressure will push towards our region on Sunday, with
continued drying and a weakening flow expected to finally end the
lake snows by Sunday afternoon. This ridge will bring sunshine to
our region through the day Sunday, but it will remain chilly with
highs in the 20s.

High pressure across the region Sunday night will provide mainly
clear skies and light winds. With favorable radiational cooling
conditions expected hedge below consensus temperature guidance,
especially east of Lake Ontario.


Surface high pressure will settle across the southeastern states
Monday, while a warm front crosses WNY Monday afternoon and across
the North Country into Monday night. Though the warm front appears
to be rather dry, a few showers across the North Country can`t be
ruled out for Monday night. Temperatures will warm up into the mid
to upper 30s east of Lake Ontario, while low to mid 40s can be
expected elsewhere.

High pressure will remain centered off the southeast coast Monday
night through Tuesday before shifting further east into the Atlantic
Wednesday, which will cause a prolonged period of southwest flow and
warm air advection across the Ohio Valley and into the Northeastern
States. Meanwhile the building ridge aloft will cause warming each
day along with continuing dry weather. Highs Tuesday will warm up
into the mid 40s across the North Country and upper 40s to low 50s
elsewhere. Wednesday will be one of the warmer days of the week
seeing temperatures climb up into the mid 50s to low 60s.


A mid level trough advance from the Northern Plains Wednesday
night to the Great Lakes by Thursday night. Deep moisture will
gradually increase Wednesday night, with a pre-frontal trough
possibly bringing a few rain showers overnight. A better chance
of rain showers will arrive Thursday and Thursday night as a
cold front slowly approaches and then crosses the eastern Great
Lakes. Both the ECMWF and GFS model guidance packages continue
to suggest a wave of low pressure may move along the frontal
zone late Thursday and Thursday night, which would enhance
rainfall potential. Thursday will still be warm, with highs well
into the 50s and possibly lower 60s if there is enough dry

Colder air will filter back into the region Friday as cold advection
increases behind the cold front and the mid level trough reaches the
eastern Great Lakes. The mid level trough may produce a few more
scattered showers Friday and Saturday, which may mix with some wet
snow during the evening and nighttime hours.


Mainly VFR flight conditions outside of snow showers, however
there will be a 3-4k cloud deck persistent across the area. Lake
effect snow showers will briefly produce lower visibility and
MVFR cigs, but should only impact any given location briefly.
The best chance for these is at KJHW and KROC in the northwest

Lake snows will continue tonight, but lowering inversion heights will
cause these to be even more scattered in nature. VFR to occasionally
MVFR cigs in lake effect clouds.

High pressure will build towards the region on Sunday with clearing
skies and conditions improving to VFR across the area by Sunday


Sunday night through Wednesday...VFR.

Thursday...VFR/MVFR. Showers likely.


Northwest winds will continue to bring choppy waves in ice free
areas to Lake Erie and the southern shoreline of Lake Ontario. With
winds 15 to 20 knots, will maintain low-end small craft headlines
through tonight. High pressure will build across the eastern Great
Lakes by Sunday, allowing winds and waves to diminish. A warming
airmass will limit wave potential on the lakes into middle part of
next week.


A significantly warmer pattern will start on Tuesday and this will
result in increasing snow melt and associated run-off. There is
still significant snow pack in place, especially across higher
terrain and in the woods. The warmest temperatures will be on
Wednesday and Thursday, with showers on Thursday likely to add
a quarter inch or so to the run-off.

MMEFS ensembles suggest that the risk for rivers and creeks to
flood from run-off alone is fairly low. If rainfall amounts are
higher than expected, there`s a low risk that some rivers and
creeks would flood on Wednesday or Thursday, with the Buffalo
Creeks and Allegheny River the most vulnerable to this.

Any risk for flooding will come later for the Black River basin.
There`s much more snow pack in place in this basin, so the main
risk is a more prolonged warm period. Highest flows in the Black
River basin will be late this week or next weekend, however the
overall risk is still a fairly low one.

The greatest risk of flooding is from ice jams along the
Buffalo Creeks, mainly near where they flow into the Buffalo
River. High flows from last week left ice jams in place, and
cold weather since then has frozen these in place. As flows
increase mid- week there`s a risk of ice jam flooding before
these dislodge. It`s difficult to predict if these jams will
break up quickly or remain in place long enough to cause
flooding. It does appear that the warm up this week will
eventually flush out most of the remaining ice on the Buffalo
Creeks, and also will melt most of the snow pack south of Lake


MARINE...Small Craft Advisory until 10 PM EST this evening for LEZ040-
         Small Craft Advisory until 1 AM EST Sunday for



NEAR TERM...Apffel
LONG TERM...EAJ/Hitchcock
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