2002 Annual

Monday, 14 January 2002: 2:29 PM
The Teller, Alaska Snow Event of October 31, 2000
Eric L. Stevens, NOAA/NWS, Fairbanks, AK
Heavy snow showers dropped 12 inches of snow in 12 hours at Teller, Alaska on October 31, 2000. This was a “lake enhanced” event where synoptic-scale forcing and lake effect mechanisms combined to produce heavy snow. While the most significant baroclinic instability was over the Alaska Peninsula and the Gulf of Alaska, the remnants of a dissipating occlusion remained over the northeastern Bering Sea as a stationary surface trough. A weak 500mb vorticity maximum was moving from south to north over the Bering Sea and provided a moderate degree of lift above the surface trough. Alone, these modest synoptic-scale features could not have produced a foot of snow–but with the addition of heat and moisture fluxes into the boundary layer over the open ocean, the environment became favorable for localized heavy snow showers along the surface trough.

The National Weather Service diagnosed this event as it developed and issued a timely and accurate warning. This success was made possible, to a large degree, by the modernized hardware deployed between 1990 and 2000. AWIPS allowed forecasters at the Weather Forecast Office in Fairbanks to effectively interpret a variety of data sets, including radar, satellite, radiosonde, and numerical model data. If this same event had occurred in 1990, before the deployment of AWIPS and other modernized hardware systems, the event may have gone undetected and unwarned.

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