LAKE EFFECT STORM "GERONIMO"
Sun. February 20, 2000
This event was a rather brief but intense one...primarily focusing on the Tug Hill region east of Lake Ontario, with a secondary maximum east of Lake Erie.
It began during the early morning of the 20th in a very moist airmass left over from a large synoptic storm which passed through the region on 18-19th. The parameters were decent but not that impressive...but the very moist airmass was the key ingredient. The 850 vs Lake temp differential was about 15C, there was little directional wind shear, and the inversion/equilibrium level was fairly high at 7-8,000 feet.
A single band developed across far northern Oswego and south-central Lewis county...and remained nearly stationary for 6-8 hours before drifting south later in the afternoon following a subtle trof passage. Over 6 inches fell within a 15-mile wide band...with a maximum of 17 inches at Redfield. Winds veered through Sunday evening and the band remained fairly intact as it drifted south across Oswego county into the Syracuse area...as well as Wayne county...but accumulations were only in the order of 2-3 inches as the band did not stay over one area very long. Ridging killed the activity Monday (21st) morning.
To the west...the largely open eastern basin of Lake Erie contributed to a general 2 to 4 inch snowfall across southern Erie and Wyoming counties through the day. This was a bit surprising...but the lake was more open than originally thought.
Overall...the MM5 model did well in pinpointing the location and timing of the activity off both lakes...but under forecast the precipitation totals east of Lake Ontario. The Eta model was not bad either...but veered the winds too quickly on Sunday so it underestimated amounts too...because the bands remained stationary longer than anticipated. Therefore, the event was underforecast.
This was a fairly localized although intense event in a sparsely populated area. Therefore..."Geronimo" rates as a 2-flake Storm.
.N.Osceola. 12 inches
.Highmarket. 11 inches
.Boonville... 9 inches
.Sandy Creek. 8 inches
.Oswego (E).. 7 inches.
Colden....... 4 inches
Flake Scale **