Wednesday, July 22nd, 2009

Rocky Mountain National Park Weather Forecast

Prime time warm, dry, and stable summer conditions persisted over most of the past week in the mountains of RMNP.

The Week in Review

A strong ridge of high pressure over the Great Basin produced dry, warm, and subsident north- northwesterly flow over CO. 

This ridge supplied the perfect weather conditions for attempting more committing high-alpine routes, as the threat of afternoon convective storms was absent.  The most stable (storm-free) conditions occurred from last Thursday through Saturday    (July 16 - 18).

Moisture increased again along the eastern slope of the Divide on Sunday through Tuesday          (July 18–21), producing isolated afternoon showers and thunderstorms, with the greatest coverage and intensity occurring over the eastern foothills and adjacent plains.

A drier and more stable airmass worked its way back into the region from the northwest on Wednesday (July 22), once again reducing the risk of deep convection. 

However, higher moisture levels persisted along the lower eastern slope, which, when transported upslope during the afternoon hours, initiated more thunderstorms over the higher foothills just east of the Park.

The Upcoming Week

A couple more days of relatively dry and stable conditions will persist before the afternoon thunderstorm risk increases again. 

Thursday will be the more stable day of the two, as moisture begins to gradually increase later on Friday.  Isolated afternoon storms are still possible, particularly over the eastern sections of the Park, where low-level easterly-upslope moisture transports occur.

The ridge will begin to migrate southward over the weekend, as lower pressure develops over the northern Rockies. 

A weak weather disturbance combined with increased atmospheric water vapor will increase the risk of afternoon storms, particularly on Saturday.

A relative lull in convective activity may occur early next week before a larger area of low pressure develops just north of the region by mid week. 

If this weather forecast scenario verifies, temperatures will cool significantly and widespread convective precipitation would be likely. 

There are currently discrepancies between the different forecast models during that time frame, so stay tuned to the short-term forecast for a more accurate forecast.

click chart to enlarge


On the trail between Mills and Black Lake in the Glacier Gorge of RMNP.

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