AVERAGE TEMPERATURES FOR THIS TIME OF YEAR;
-At about 8,000 feet (Aspen): Low 37, High 65 (Highest ~ 80 on May 21, 2005, Lowest ~ 20 on May 21, 2001) -At about 9,000 feet (Dillon; near base elev. for Keystone, Breckenridge, Winter Park); Low 27, High 61 (Highest ~ 76 on May 20, 1954, Lowest ~ 0 on May 22, 1933) -Approx 13,000 feet (Near the top elevation of many resorts in CO); Low 23, High 46


::: Cooler with showers and some snow today (winter like)/ Milder with more sun Tuesday/ Increased afternoon thunderstorms on a warmer Wednesday/ Milder and drier Thursday through Sunday :::

DETAILED SUMMARY for the week -> Updated for Monday, May 20... Today - Temperatures are chilly, with snow to low-ish elevations for late May, and some snow accumulations, as an unseasonably cold low pressure system now sits across the Dakotas, with some upper level energy, and enough moisture to deliver some higher elevation snow accumulations.

Tuesday and Wednesday - High pressure ridging builds in some, with mostly sunny skies developing on Tuesday (then isolated afternoon thunderstorms), and the same mostly sunny skies but noticeably warmer temperatures on Wednesday. Afternoon thunderstorms increase on Wednesday, as moisture lingers, and the warmer temperatures help to trigger the increase. 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 but still remains mostly south and east (placing the area between low pressure to the northwest and high pressure centered to the southeast), in response to another unseasonably cold low pressure system sitting across the northwest US. Due to a southwest wind flow overhead, we expect a conditionally unstable atmosphere (the condition being certain -trigger- temperatures, daytime high temps) with limited moisture for just isolated (but decreasing each day) thunderstorms and showers in the afternoon and early evening, after warmer and mostly sunny days.CM

-26 May to 01 June, 2013 - 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 southeast US, placing Colorado and New Mexico under a continued southwest flow aloft. Isolated mainly afternoon thunderstorms and showers develop at times (mainly afternoon hours) under this pattern. Otherwise, we expect warm temperatures under mostly sunny skies, with some drying winds.CM