Ahead of a weak Pacific trough, some summer style ACSL was spotted NW of Boulder this AM. Hints of early fall. #COwx pic.twitter.com/u3q85Vt2
— NWS Boulder (@NWSBoulder) August 11, 2012
ACSL = Altocumulus Standing Lenticular (clouds).
Associated Wave Cloud shown here. Likely CCSL near 36000ft above the ACSL with cloud temps at -44°C or -47°F. #COwx pic.twitter.com/NdmsIAU4
— NWS Boulder (@NWSBoulder) August 11, 2012