Thursday, June 10th, 2010

The big melt down continued for a second consecutive week across the high country of RMNP and much of it will likely freeze solid in a forecast winter storm.  Time to sharpen the tools and get out in the mixed terrain this weekend in what will likely be the last winter storm of the season!

The Week in Review

The warmest conditions of the week occurred on June 4-7, when the daytime thermometer pegged in the 55-62 F range near treeline.  During this time, the snowpack rapidly unlocked its liquid content and caused creeks and streams to run rampant.

The snowpack that had been overlying the Bear Lake snow pillow for the past eight months disappeared by weeks end, where over seven inches of snow water melted in just seven days.

This rapid release of snow water across the Park caused the flow rates in the Big Thompson to nearly triple last week’s already elevated rates.  The river flows near Estes jumped from 300-400 cubic feet per second (cfs) to nearly 1000 cfs within two days after the most intense heat settled in.

While a good fraction of the week was also quite cloudy owing to the moist onslaught in the Pacific Northwest, we managed to squeak out a couple of clear nights during the heat wave.

During these times, strong radiative cooling produced firm overnight and early morning snow conditions followed by perfect corn snow resulting from uninhibited solar heating during the later morning hours.

The Upcoming Week

Two more days of warm summer weather will occur on June 10 and 11, before a significant change in the weather arrives in time for the weekend.

A storm system currently over the Pacific Northwest will dive southeastward and spin up over the desert southwest.  This will place northeast Colorado in a favorable position for precipitation production.

By the afternoon on Friday June 11, diffluent flow aloft combined with easterly component upslope flow along the eastern slope and unstable lapse rates will trigger thunderstorm activity across the region.

Widespread moderate to heavy precipitation will develop and occur overnight Friday into early Saturday morning.  By early Saturday morning, the freezing level is also forecast to drop to 12 kft, and with this snow will fall over the high peaks.

Precipitation is forecast to continue with less intensity through the day on Saturday. The skies will remain cloudy up to mountain-top level east of the Divide on Sunday as well, with additional shower activity forecast during the day.

The total accumulated precipitation potential for the storm is currently 1-1.5 inches along the higher eastern slope, with 3+ inches over the higher eastern plains.

Weather conditions will slowly improve on Monday before warmer and drier weather move in on Tuesday and Wednesday, June 15-16.

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.