January will continue current rainless pattern

The New Year has begun in much the same meteorological fashion as the old year concluded: Cool and dry. If long-range forecasts are accurate, the month of January, climatologically the wettest month of the year, will unfortunately follow in the relatively rainless footsteps of its 2008 predecessors with below-normal rainfall for a month that on average supplies nearly 20 percent of our total annual precipitation.

The culprit in this abnormally dry scenario is our old nemesis from similarly low-rainfall years of yore — a jet stream positioned too far north to bring substantial, moisture-laden Pacific storms into the North Bay with any sort of regularity. Instead, the Napa Valley has frequently found itself this year on the extreme southern edge of systems which have brought copious amounts of rain and snow to the Pacific Northwest and inland along the northern tier of the United States. Places like Portland and Spokane were blanketed last month by record-breaking snowfall with the latter reporting more snow in December than it normally receives in an entire year. Heavy rains on top of the deep snow pack have recently resulted in a bout of flooding on many Washington and Oregon rivers and creeks, as the onslaught of wet Pacific storms continues unabated.

Regrettably, Mother Nature’s munificence has not extended much south of the California/Oregon border and — after a weak system that was slated to drag through the area on Monday with a negligible amount of rain along with another of the same anemic ilk on Thursday — the outlooks generated by several of the weather models were all unanimous in their depressingly dry forecasts up through the middle of the month.

Both the GEM (Global Environmental Multiscale) and the GFS (Global Forecast System) models concurred that high pressure would build strongly into the eastern Pacific in the wake of Thursday’s non-event, shoving the jet stream even further north while providing a warm-up that could send afternoon temperatures into the mid-60s under sunny and dry skies. This pattern may persist, if the models are correct, even into the third week of January.

That bit of distressing news coincided with the rather disappointing results of the initial Sierra snow pack survey of the year, which indicated an improvement with respect to snow water content compared to one year ago — though this year’s readings were still below normal for the date. Several good snowfalls in December helped to boost the numbers in the mountains, but an extended January dry spell will surely make for a less sanguine snow situation as we head deeper into the winter. Many locales which are dependent on Sierra snowmelt for their water supply are facing almost certain rationing this summer — barring a dramatic turnaround in our current dry weather pattern, the blame for which may be ascribed to a cooler than normal pool of water in the Pacific, which is inhibiting the propagation of lower latitude storms of any significance.

Your weatherperson promises to exert whatever influence he may have with the weather gods in order to bring a return to our normally wet winter. A generous cash donation or two might go a long way toward assisting him in achieving that special level of concentration demanded by such an endeavor, though local checks made out to the “Make It Rain Foundation” will gladly be accepted — particularly those of three figures or more. Rest assured that a full 13 cents of every dollar will go directly to the cause. Every month you will receive a report with actual photos of the clouds your contribution is helping to sponsor as well as a brief message from the “Great Rainmaker” himself. Act now — your 2009 grapes will thank you for it!