5.5
A lake effect snowfall in Western Nevada—Part I: Synoptic setting and observations
Mary M. Cairns, NOAA/NWS, Reno, NV; and R. Collins, T. Cylke, M. Deutschendorf, and D. Mercer
The state capitol of Nevada, Carson City, experienced a rare lake-effect snowfall during the first week of November 2000. Within a two-day period, over 58 cm (23 in) of snow fell in Carson City as a result of lake effects from Lake Tahoe, CA. Several surrounding smaller lakes in western Nevada experienced up to 25 cm (10 in) of lake-effect snow during the same time period.
The forecasters at Reno, some whose experience covers over 25 years in the local area, had never experienced such an event. Lake effect snow is typical in the Northeast over the Great Lakes, as well as over the Great Salt Lake in Utah. Lake Tahoe and Pyramid Lake are considerably smaller in size, but were able to produce significant snowfall during the three-day period. These events presented a challenge to the Reno Forecast office. The forecasters also had high-resolution numerical guidance available during the event, a local 15-km MM5 model and a 12-km workstation-version of the Eta model. Even with the use of these tools the forecasters did not realize the potential of the lake-effects.
Snow fell in western Nevada for three days, centered over the state capitol. The first day 15-36 cm (6-14 in) fell in a small band to the west and south of the city. The second day, prior to and during a Veterans' Day Parade, an additional 15-23 cm (6-9 in) fell along a corridor from Carson City to about 16 km (10 mi) northwest of town. In addition, similar reports were reported along the southeast portion of Pyramid Lake. Day three found snowfall amounts of 10-15 cm (4-6 in) in a period of four hours on the southwest side of Pyramid Lake, again a result of lake-effect snow from another direction due to local wind flow.
This paper presents the first of three studies on this unique event. The first study focuses on: 1) the prevailing synoptic conditions immediately preceding and during the lake-effect snow event which produced this phenomenal snowfall; 2) an examination of the numerical guidance available for the event along with a comparison to lake-effect snowstorms of the Great Salt Lake in Utah; and 3) the history of the storm. The second paper submitted to this conference ("A Lake Effect Snowfall in Western Nevada Part II: Radar Characteristics and QPE" by Huggins at al) presents the radar characteristics throughout the storm, and reviews the quantitative precipitation estimates from the WSR-88D using a new-improved algorithm developed between the University of Nevada's Desert Research Institute and the NWS in Reno. A third related paper, "A numerical simulation of a rare lake-effect snow event in Western Nevada" by Cairns, Corey and Koracin has been submitted to the 14th Conference on Numerical Weather Prediction.
Session 5, Operational Use of Analysis for Forecast Development
Thursday, 2 August 2001, 8:00 AM-10:00 AM
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