Thursday, April 1st, 2010

Rocky Mountain National Park Weather Forecast
 

Last week was one of the windiest weeks of the year in RMNP, with wind gusts exceeding 50 mph on 6 of the last 7 days above 12 kft.

The Week in Review

A majority of these high winds occurred under west through northwest flow near mountain top, which continued to form new drifts and slabs on lee- and cross-loading terrain features above treeline.

Slab avalanches remain a concern in these higher elevation zones, where dry winter snow remains on cold and shady aspects. 

While the strong spring sun and warming temperatures are increasing the wet avalanche risk on southerly aspects, the strong and persistent winds have kept the near surface snow cool and relatively dry owing to turbulent mixing and sublimation.

Winds turned to the southern part of the compass on 3/31 in advance of a large Pacific weather system.  While some additional snow transport has occurred on northerly aspects, winds have substantially subsided with the change in direction and subsequent break down of the mountain wave.

Last Friday’s (3/26) finicky spring storm tracked one county too far south. This left RMNP with some snow shower activity and minimal snow accumulations, while parts Indian Peaks picked up several inches of new snow under 2 inch per hour snowfall rates.

The Upcoming Week

 An active late season wave train of energy will continue to propagate across the eastern Pacific and over the western US, which will keep the weather over RMNP windy and unsettled over the next week.

Three storm systems are forecast to cross the Rockies on 4/1, 4/3, and 4/5.  The first and third systems are the strongest and moistest. 

However, the structure and position of these two systems will favor heavy snowfall for the central mountains of CO, while the northern mountains of CO are only expected to pick up the occasional but frequent moist leftovers.  

The greatest probability for new snow will occur for RMNP under northwesterly flow in the post-frontal environment following the passage of each storm axis.

Winds directions will vary from the southwest during pre-frontal flow and west through northwest during post-frontal flow.  A brief window of lower wind speed opportunity may present itself on Fri (4/2) for attempts at higher elevation objectives.

A large region of high pressure is currently forecast to build over the region by mid to late next week.  This would bring warm spring conditions and low wind speeds to the high country of RMNP, and an increasing threat of a wet avalanche cycle.

Detailed 7-Day Forecast

NWS Forecast for the 12,000 foot level near Longs Peak 

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

Weather Observations and Forecasts

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