LAKE EFFECT STORM "ASPEN"
November 14 - 15, 2000
Lake Flake Scale: *
Maximum Snowfall: Lk. Ontario ( N.Osceola) 8"; Lake Erie (Perrysbg-Sprngville) 6".
Duration: 24 Hours
Prime Feature: Rain-Snow line (boundary layer warming by lakes)
Lake Effect storm "Aspen" was the first of the 2000-01 season for western and central New York. It was a marginal event with maximum snowfall of about 6" off Lake Erie and an isolated 8" report over the southern Tug Hill off Lake Ontario...but it was the first of the season and did feature some unique features...most notably the rain/snow line.
The event began during the afternoon of the 14th. Cold air had been pouring into the Rocky Mountain and Plain States for several days and had become entrenched across the entire region west of the Mississippi. The long wave pattern had kept the east mild and dry however...and our region shared in the tranquil mild conditions which prevailed through October and the first half of November. However...a deep storm moved up across Lake Superior on the 13th and cold air began to sweep eastward in its wake. The cold front crossed western New York during Tuesday (14th) morning and central portions of the state by early afternoon. This front was preceded by a general rainfall. Colder air deepened during the midday and early afternoon across the west...and as another trof approached...a band of lake effect precipitation developed on a 220 vector over eastern Lake Erie and pushed across the Niagara Peninsula by noon. This band slowly sagged southward as the winds veered steadily...to 240 by 2 pm. 0.1 to 0.25 inch of precipitation...mostly wet snow and graupel...fell across Niagara and northern Erie counties through 4 pm when increasing shear and NVA caused the band to break up some. However...a stronger trof approached from eastern Michigan during the evening...creating more uplift and reducing shear so the band re-established itself and consolidated during the early evening hours right across the Buffalo metro area. It remained nearly stationary until about midnight when this trof passed...shifting winds to west and causing the band to drop south across southern Erie and eventually into the northern portions of Chautauqua and Cattaraugus counties toward morning. The activity broke up and became more cellular by noon on the 15th as the inversion dropped and diurnal mixing occurred. Warm advection cut it off entirely by mid afternoon.
A unique feature of "Aspen" was the strong modification of the boundary layer (within several hundred feet of the ground) by the 54 degree waters of Lake Erie. With the overall conditions just marginally cold enough for snow anyway (850's near -6, thicknesses near 528 etc.), the air was warmed enough so that nearly all of the precipitation fell as rain over the city of Buffalo...with a rather abrupt change to snow several miles inland. This changeover line was near the NY Thruway in its north-south section just east of Buffalo. We often see wide variations in snowfall amounts across our region due to the narrow nature of snowbands...but it is very rare that we see such a distinction within the same band. Buffalo Airport received about 3" of snow...while the city about 0.5 inch of rain but just a trace of snow. Most of Buffalo’s eastern and southern suburbs received 2-4" of snow. You can check out the model indication of the surface temperature field unde the snowfall map.
A similar scenario occurred further south along the lakeshore with Silver Creek and Dunkirk receiving just rain...while areas just a few miles inland...but 800 feet higher...caught 4-6" snow.
East of Lake Ontario...the event began before dawn on 15th over southern Jefferson and northern Lewis counties...then settled south across the Tug Hill and Oswego county before weakening late Wednesday (15th) afternoon. The band became intense with good fetch early in the morning..with 7" falling in 4 hours at North Osceola on the Tug Hill. Thunder was heard as well. Much of eastern Oswego county received a few inches...but once again...the boundary layer was sufficiently warmed by the lake so that just rain fell at Oswego...and a mix inland to Fulton. Accumulations were restricted to areas over 10 miles from the lake.
"Aspen" caused few problems as its accumulating snow occurred at night and created only a few problems on area roadways Tuesday evening. Although it was the first event of the season...amounts only marginally reached our criteria for naming a storm (over 6") so we rate this as a 1-Flake Storm. *