AVERAGE TEMPERATURES FOR THIS TIME OF YEAR;
-At about 8,000 feet (Aspen): Low 35, High 63 (Highest ~ 78 on May 16, 1988, Lowest ~ 22 on May 14, 1985) -At about 9,000 feet (Dillon; near base elev. for Keystone, Breckenridge, Winter Park); Low 26, High 58 (Highest ~ 73 on May 17, 1948, Lowest ~ 9 on May 16, 1916) -Approx 13,000 feet (Near the top elevation of many resorts in CO); Low 21, High 44


::: Cooler with showers and some snow today and Monday/ Milder with more sun Tuesday and Wednesday/ Milder with increased afternoon-early evening thunderstorm activity Thursday through Sunday :::

DETAILED SUMMARY for the week -> Updated for Sunday, May 19... Today and Monday - Temperatures become a bit colder, with snow to lower elevations, and some snow accumulations, as an unseasonably cold low pressure system sweeps through the Rocky Mountains with some upper level energy, and enough moisture, especially on Monday (mostly late Monday and Monday night), to deliver some respectable snow accumulations.

Tuesday and Wednesday - High pressure ridging builds in some, with mostly sunny skies developing on Tuesday, and the same sunny skies but warmer temperatures on Wednesday. An even stronger low pressure system develops across the northwest US, and this one looks quite unseasonably cold.

Thursday through Sunday - High pressure ridging builds in stronger from the south, in response to another unseasonably cold low pressure system sitting across the northwest US. Due to a south-southwest wind flow overhead, we expect a conditionally unstable atmosphere (the condition being certain -trigger- temperatures, daytime high temps) with enough moisture for increased thunderstorms and showers each afternoon and early evening, after warmer and mostly sunny days.CM

-25 to 31 May, 2013 - Into the following week, we expect strong and unseasonably cold low pressure remain across the northwest US (mountain snow to unusually low elevations in the Cascades of WA and OR), and upper-level high pressure ridging sitting across the southwest US, placing Colorado and New Mexico under a continued southwest flow aloft. Isolated to scattered mainly afternoon thunderstorms and showers develop each day under this pattern. Otherwise, we expect warmer and warm-ing temperatures.CM