Atmospheric River in the Pacific Northwest and Northern Rockies this Weekend

A Pacific storm and atmospheric river will impact the Pacific Northwest states and northern Rockies this weekend, bringing locally heavy low elevations rain and heavy high elevation snow in the mountains. By Sunday over the Interior Northwest, rain combined with snowmelt will increase the risk of flood hazards. Flood Watches are in effect. Read More >

December 15, 2005
Winter Weather Event Review
Section 1: Introduction

Back to the main research page for December 15, 2005

Section 1 -- Section 2 -- Section 3 -- Section 4

On the morning of Thursday, December 15, 2005, a weak surface low moved along a frontal trough as it moved from west to east through the Ohio Valley. The previous night (Wednesday night), rain fell ahead of the frontal trough with surface temperatures dropping to just above freezing. As the frontal trough and weak surface low moved into Ohio and Kentucky, surface temperatures around or just above the freezing mark stayed nearly steady throughout the day. Precipitation began in the pre-dawn hours as rain or a mix of rain and snow. It quickly transitioned to all snow and increased in intensity across east central Indiana, through the Miami Valley, into parts of central Ohio.

Snow accumulations of 3 to 5 inches were found from Richmond, IN to Marysville, OH. This study will focus on the subtle differences in model trends, thermal fields, and forcing that made this a difficult and uncertain precipitation type forecast.

Note, all times in this document will be for December 15th unless noted.

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