A unique perspective on Colorado weather by a former climate analyst at NOAA's Climate Prediction Center.
Sunday, December 5, 2010
Pattern Continues to Imperil Snowlovers' Sanity
We have had near record-low snowfall over the past 6 weeks, and it appears that the pattern of much below-normal precipitation coupled with near- to slightly above-normal temperatures will persist for at least the next 10 days. By that point, if we compare to previous year's October 15 through December 15 statistics, it is quite likely we'll qualify for one of the least snowy periods on record.
But snow is not only an aesthetic thrill for those who love it, it's also important for our water tables. As I said in my previous post, we're now officially experiencing "moderate drought conditions"; assuming this dryness lasts for another two weeks (which I think is quite probable), by the end of the month we may be bumped into the "severe drought conditions" category by NOAA/USDA.
What's the reason for this exceptional dryness? Well there are a number of contributing factors, but the most obvious one is a jet stream that has more-or-less, except for brief exceptions, stayed farther north than average over the western US (resulting in a ridge of high pressure), and farther south than normal across the eastern half of the country (resulting in a trough of low pressure.) This has our region (with the exception of high country, which has experienced upslope snow events) experiencing much drier than normal conditions, with most storms impacting locations north and east of central Colorado.
Though it would be unwise for me to postulate about conditions nearly 3 weeks from now, I'm beginning to think that the odds or a White Christmas this year across the metro area are less than 50/50, though this dry pattern can't hang on forever; perhaps we're in store for a big dumping during the last third of the month...