Lake Effect Storm Amaryllis - December 10-12, 2009
Maximum Snowfall: Lake Erie 27"
(Springville); Lake Ontario 40" (Highmarket)
Duration: 54 hours +/-
Feature: Classic WSW event,
all ingredients prime. Well inland extent.
The 2009-2010 lake effect season got off to a belated start, but its initial storm was a very impressive one, indeed a "Classic" event. It
came on the heels of a huge storm that traversed the nation from California to the Great Lakes,leaving a strong cold west to southwest flow
in its wake. All the ingredients were there for a major event for our area, strong unidirectional flow, good moisture, increasing instability
as 850 mb temps fell into the -10c to -13c range for prime snow growth. Lake temps were in the 5-7c range. Its only mitigating factor was the
very strong winds, 60 kts at 800 mb, which delayed organization a few hours. Still, this also aided in an unusually far extent of snowbands,
with significant accumulations off Erie well into the Rochester metro area.
The event began rather slowly as marginal temperatures and strong southwest winds kept activity from getting too organized on Wed night
Dec 9th, finally after midnight, a snowband set up on a 230 flow across northern Erie and southern Niagara counties, which settled south into
southern Erie/Wyoming by mid morning Thursday after dropping 2 to 4 inches. A short wave then approached and lifted the band northward for
several hours during the day, a bit further north than expected, across the metro Buffalo area and on across Genesee and Monroe counties with
several inches, then settled slowly south and stalled out for many hours during Thursday evening 10th with very intense snowfall rates across
the Buffalo South Towns and on into Wyoming county. This band also dropped down across the lakeshore areas of Chautauqua county with intense
rates with major implications on the NYS Thruway. The activity dropped further south and set up across the southern tier counties for much of
Friday, with some locally heavy amounts around Chautauqua Lake in the afternoon. Drier air advected in during the evening and the Erie
activity weakened and ended by midnight.
Off Lake Ontario, a similar scenario ensued, albeit several hours later. The band initially set up in the Watertown area Thursday morning and
slowly settled south later Thursday into early Friday (11th) with intense rates across southern Jefferson and central Lewis counties. The band
then settled further into southern Lewis and Oswego counties later Friday as winds veered a bit further and most of Friday night before
weakening Saturday morning as the drier air advected in.
This was quite an event to start the season. Surface winds were very strong with resulting in considerable blowing snow and whiteout
conditions at times. The NYS thruway was closed between Dunkirk and the PA line with hundreds of motorists stranded. The Buffalo and Rochester
metro areas were affected as well, although major impacts were restricted to Buffalo's South Towns. Snowfall totals were extreme in the
heavier areas. It therefore earns five ***** stars.
Off of Lake Erie...
||3-9 inches (N to S)
||2-8 inches (N to S)
Off of Lake Ontario...