Thursday, July 9th, 2009

Rocky Mountain National Park Weather Forecast

After a resurgence of subtropical moisture a week ago, a gradual and continuous drying trend brought increasingly stable blue skies back to the mountains of RMNP.

The Week in Review

Showers and thunderstorms accompanied the subtropical moisture surge, and extensive cloudiness persisted during the overnight hours.

As the atmospheric flow transitioned from southerly to southwesterly over the holiday weekend, a drying and warming trend ensued. 

During this time of the year for CO, westerly-south westerly air trajectories from the eastern Pacific generally bring the driest conditions to the region.  In contrast, southwestly-southerly trajectories from the AZ, NM, and MX produce the most unstable, moist weather.

Bone dry and super stable conditions arrived on Wed., which provided perfect weather conditions for committing high alpine adventures.  

These perfect ‘Diamond’ days climatologically occur less frequently during the months of July and August, when the North American Monsoon typically becomes active over CO.

The Upcoming Week

One more bomber Diamond day will occur on Thu., before moisture levels begin to rise and bring an increased risk of afternoon convection.  These stable, storm-free days typically occur when vertically integrated water vapor levels are near or below 6-7 mm over the higher terrain.

An anticyclone is forecast to build to our south over the weekend.  This will act to warm the atmosphere and transport moisture in from AZ and MX.  This increase in moisture will fuel afternoon convection; however concurrent warming of the mid levels will help to delay or limit the formation of deep convection (t-storms) during the afternoon.

click chart to enlarge

The NWS numerical forecast for the mountains of RMNP over the upcoming weekend is as follows:

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