The weekly weather forecast for the high country of Rocky Mountain National Park, Colorado; researched and written by professional meteorologist and avid mountaineer: Dan "the weather man" Gottas.
Thursday November 6, 2008
The Week in Review
A taste of winter was served to the mountains of RMNP this last week. Since last Sunday, when the leading edge of the cooler airmass began to move in, temperatures have dropped 30-40 degrees F from the balmy readings of preceding days.
And holding true to northern CO form, it wouldn’t be a true weather event without a good dose of wind. With each period of disturbed weather on Sunday/Monday and Wednesday/Thursday, wind gusts cranked in the 60 mph range. These winds combined with single-digit temperatures to produce raw conditions near and above treeline on Thursday (-10 to -20 F wind chills).
Precipitation amounts were light, with 1-2 inches on Monday and 3-6 inches on Wednesday. Wednesday’s snows were greatest over the western section of the park, while the more limited new snow over the eastern side of the park has already been scoured, transported, or sublimated away.
On a positive note, the deep cold snap of the last three days has likely been quite beneficial for ice growth on ground-water fed features in the sub-alpine zones of the park.
On a cautious note, the avalanche risk has likely increased in regions prone to drifting due to the recent northwesterly winds and new snow. In some cases, these wind slabs are resting on a weakly-bonded, surface-based facet layer.
The Upcoming Week
With the current state of the global ocean and atmosphere reflecting La-Nina conditions, the strengthening western US storm track over the last and upcoming week resembles such conditions. As was so often observed during last year’s La-Nina, storms will make landfall along the Pacific Northwest coast and then will track southeastward toward CO. This will reinforce the current unsettled weather pattern over RMNP during the next week. Specifically, two storm systems currently have their sights on CO – one on Sunday and another on Wednesday/Thursday.
With the jet stream developing so far south, the recent strong winds are actually expected to decrease over the mountains as the storm develops and tracks over CO on Sunday. Another opportunity for precipitation will accompany this storm, with 0.2 – 0.4 inches of liquid equivalence currently forecast to fall from Sunday through Tuesday.
The next system, which is currently taking on different shapes from one model run to the next, will affect the mountains in some form on Wednesday and Thursday. This system will likely bring strong winds back to CO, with orographically-forced and jet-stream induced snows for the northern mountains. If these two forecasted factors verify to coexist, significant snows are probable for northwest-facing terrain, particularly near and west of the Divide. Lead boots and suits of armor may be useful for the ‘breezy’ foot travel above treeline during this time.
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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