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Niwot Ridge LTER Snow Report for December 2004 Positive snow pack conditions continue to favor the lower western US, and Colorado as of today. The pattern reported at the start of this month continues in bothe western US and Colorado (dry north, wet south-western states), and promises to continue into early 2005 (NOAA CPC Dec 6 report on ENSO conditions). Here on Niwot Ridge, the snow pack is almost average. The hand measurement shows 4.875" of water (90% of past 23 year average). The Snotel network shows 5.1", or 98% of average, and cumulative winter precipitation of 119% of average. Either way, this years snow pack is much better than last, which was 51% of average at this time. The State of Colorado is also in good shape, loosely mimicking the western US as a whole, in that the south is generally wetter than the north. The similarity ends there, though, because even the northern Colorado basins are not much below average. The state shows 96% SWE and 97% PPT (snow water equivalent (SWE)/cumulative winter precipitation (PPT)). The South Platte basin shows 92%/94% of average SWE/PPT, respectively. The Gunnison basin is still tops with 120% / 113%, SWE/PPT, respectively. The Yampa/White is still in last place with 87% and 93% of average values, respectively. The southern basins of the Rio Grande, and the San Juan/Dolores/San Miguel/Animas are doing very well with 116%/116% and 109%/107%, for SWE/winter precipitation, respectively. Also noteworthy, most of Colorado basins are showing Snowpack Indicies (SI) of near one, meaning the winter weather is also about normal, so far. The western US snow pack pattern is also little changed from the start of this month, but is much more extreme compared to Colorado. Washington has only 39% of average snow pack (73% of PPT, however), and Oregon has 48%/67%, respectively. Utah still is tops with 137% SWE and 152% PPT. The California Great Basin sites show 123%/97%, and Arizona shows131%/140%, SWE/PPT, respectively. Colorado, Nevada, New Mexico are about average, and Idaho, Montana and Wyoming are lagging with 72%, 69%, and 81% of average SWE, respectively. Low or high snow pack, however, most all states show SI's of less than one (weather conditions less conducive to snow pack development given the amount of winter precipitation received), with the exception of the California Great Basin sites, and Colorado. Looking "upstream" for clues for the rest of winter we find no strong indicators. The NOAA CPC predicts continued weak El Nino conditions in the Pacific into early 2005, and although the PDO may be shifting (negative index values the past two months), it is too early to say for sure. So, weather-watching may continue to be interesting this month! Cheers! Mark
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| This material is based upon work supported by the National Science Foundation under Cooperative Agreement #DEB-0423662. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necesarily reflect the views of the National Science Foundation. Please contact lternwt@colorado.edu with questions, comments, or for technical assistance regarding this web site. |