The weekly weather forecast for the high country of Rocky Mountain National Park, Colorado. Researched and written weekly by professional meteorologist and avid mountaineer, Dan "the weather man" Gottas.
Friday November 28, 2008
The Week in Review
Overall, another benign week of weather graced the mountains of RMNP. Just above treeline, temperatures warmed above the freezing mark on several days and the northwesterly winds were most frequently in the 25-45 mph range, before slacking off to lighter speeds on Wednesday and Thursday (< 15 mph).
A change in the weather pattern occurred on Tuesday along the west coast of the US, allowing wave energy to track along the southern tier of western states. Snow arrived in Colorado on late Wednesday and Thursday, but the southern track of the storm provided little new snow for the Park (couple of inches).
Snow coverage across the high terrain remains thin to non existent. Ice routes, whose growth rates are dependent on the freeze-thaw of snow-water sources, may have benefited from some of the recent warm days.
The Upcoming Week
A strong east-Asian jet stream has been extended across much of the Pacific basin over the past two weeks. In the mean, this has forced a broad and large amplitude ridge of high pressure along the western US. This configuration has guided most weather-producing wave energy well north into Canada and along the northern-most tier of western US states.
A couple of surges of energy and a strong jet stream on the east side of the large western US ridge will force a period of mostly orographically-forced light snow across the mountains of RMNP over the weekend. Winds will be increasing from the north-northwest, with gusts greater than 50 mph likely by Sunday. The wind will scour snow from windward slopes, and will transport blowing snow into lee-side drifting zones. The strongest winds are likely to remain over the higher terrain, as the cross-mountain wind component will not be favorable for significant east-side mountain-wave development.
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In the crystal ball, the long-range forecast models are suggesting retrogression (westward shift) of the mean ridge position following next weekend. A configuration such as this would allow weather disturbances to track across Colorado, potentially bringing frequent snows, wind, and cold temperatures. This scenario would be quite similar to what transpired last year around this time, when an uneventful November gave wave to the relentless barrage of cold and snowy weather disturbances on a northwesterly storm track (thank you La-Nina). Current conditions in the tropical Pacific indicate that La-Nina is making a comeback for round two this upcoming winter season.
The NWS numerical forecast for the mountains of RMNP over the upcoming weekend is as follows:
Detailed 7-Day Forecast
The link above will take you to the National Weather Service forecast for the 12,000 foot level near Longs Peak. These forecasts are derived from computer-generated numerical forecasts, and are updated shortly after 3:30 am, 9:30 am, 3:30 pm, and 9:30 pm local time. In the lower right-hand corner of the page, one can view forecasts for other locations in the Park by clicking on the desired location in the terrain map.
Do-It-Yourself Weather Forecast Links
The link above provides a list of web links to various sites containing a variety of meteorological data and information. Collectively, these resources can be used to monitor and study current weather conditions, as well short-term, medium-range, and climate forecasts.
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