Mostly Colorado blue skies will soon fade with radar on Grand Mesa showing invading clouds on the Utah border as I write this forecast at 07:30. A powerful storm system birthed in the Pacific Northwest is riding up and over the Serria today and will close off into low pressure system in the Great Basin this afternoon. As the low deepens and builds it will drop into the 4-corners bringing showers and thunder snow this afternoon into the southern San Juan Mountains with warm temps in place in the lower elevation then gradually turning to snow above 9,000′ tonight with cooling temps.
Models are not in agreement with the forecast but do show prevalent convective storms that will precipitate with vigor wherever the convective cells/bands form but exact locations are impossible to forecast. A warm atmosphere in the lower elevations early today put rain/sleet below 8,000′ and initial snow levels above that #. This system should bring good storm totals depending on your location but we should see between 10-14″ on southwest facing terrain above 10,000′ with the potential of 2′ or more in those secret and favored locations. These pinched off 4-corner lows (happening Friday-see pressure/precip map below) can wobble around and create good precipitation rates over a long period of time.
Three models have this storm system affecting the San Juans through Saturday with precipitation diminishing from NW to SE through the day. A brief ridge of high pressure builds Sunday then the next storm of this progressive spring pattern should arrive Monday evening and last through Tuesday then clearing beginning Wednesday.
A prolonged period of very heavy snowfall in the early morning hours favoring RMP and north. Snowfall exceeded 2″/hour. This high precipitation intensity triggered multiple slides along the corridor. Snowfall has since tapered and (reportedly) will continue to do so throughout the morning. Nearby Telluride received 12″-13.5″ overnight. .
24 hour snow/water
Coal Bank 3″/.3″
High cirrus have begun their invasion of the San Juans this morning announcing a series of soon to arrive spring storms beginning tonight traveling on southwest flow. By late afternoon the quick hitting open wave should bring windy conditions, rain/sleet to the lower elevations and snow above TL through Sunday morning. Not much juice with this disturbance so don’t expect more than 8-12″ of snow in the high country.
A short lived ridge of high pressure will build tomorrow with some clearing then Monday through mid-week a more complex storm system brewing in the Pacific NW will slide into the desert southwest on Tuesday. The three models I watch all have a cutoff low forming over the 4-corners later Tuesday that should spin moisture into the central and southern mountains beginning late Tuesday/early Wednesday morning as another spring storm with up to an inch of liquid to spread in the mountainous terrain above 10,000′.
Wednesday into Friday unsettled weather prevails with NW flow remaining in the area until another spring storm moves into the area by late Thursday into Friday… Finally our unsettled spring conditions!
Tuesday’s 4-corner/cutoff low
High cirrus began invading western Colorado early this morning just ahead of a Pacific storm that will push through the west as an open trough on slight SW flow. The San Juans especially the southern SJ’s will be in the main flow late tonight through late tomorrow with up to 2′ of snow possible. Storm dynamics including a stalled surface cold front, high winds (polar jet-165 k overhead) and decent southern moisture push the storm potential. The moist subtropical jet should meet the cold front sliding south Tuesday morning causing a significant precipitation event for the southern SJ’s.
The south San Juans could receive the brunt of this moist storm with 12-24″ or more at Wolf Creek. The cold front should drop air temps allowing snowfall instead of rain in the lower elevation valleys (5 – 7,000′), something unusual this winter.
Following this storm a dry pattern for the first 10 days of March looks real. The storm track moves into the northern Rockies and B.C.