wxgeek's weather-Dry/Mild Start, Precip Friday-Update Oct 10

Update Wed Oct 10

Nice mountain wave formed this morning casting some pretty lee wave (lenticular) clouds across the Front Range. This was in response to a good west northwest flow aloft. This will also help temps warm today due to downslope winds. We will remain dry and mild today and Thursday with temps above seasonal norms.

Models remain consistent and in good agreement on the upper level low currently spinning off the CA coast, which is forecast to eject to the northeast beginning Thursday. Track of this system remains across southern NV on Friday morning, into eastern UT Friday evening, and across northeast CO/western NE Saturday morning. Precip will spread into southwest CO late Thursday night and across all of western CO Friday morning. Snow level Friday will be 9000 - 10,000 ft across western CO, lowering to 8000-9000 ft Friday night. Vast majority of precip will remain west of the Divide with this system, with only isolated showers and thunderstorms across eastern CO Friday afternoon and night. Precip amounts expected to be 0.50 to 1.25 inches across western CO, while east of the Divide will generally see less than 0.10 inches. Anyone planning outdoor activities in western CO Friday into Saturday should be prepared for winter conditions above 9000 ft, with up to 6-10 inches of snow possible at higher elevations. Travel across I-70 could become slick at times Friday afternoon and Friday night. Precip will end by Saturday morning across eastern CO, while precip may continue over western CO, especially northwest CO into Saturday afternoon.

For our foothills, only a chance for showers and isolated thunderstorms Friday afternoon and evening, with brief snow possible above 8000-9000 ft, but no significant accumulation expected. Skies should clear Saturday under breezy westerly winds but temps warming back to near seasonal norms. Sunday will be mostly sunny and dry across the state, with temps back to seasonal norms in most locations.

Long range models indicate next week will remain dry and mild across the state as an upper ridge build along the west coast, keeping the storm track well north of CO. October is beginning to look quite dry across eastern CO, unless something changes in the extended outlook.
_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

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Some beautiful early Fall weather on tap across CO early this week. Dry and mild conditions with temps near to slightly above seasonal norms. Northeast CO will get brushed by a passing system to our north on Tuesday, so temps may cool slightly Tuesday as weak cold front brings in some cooler air. Wednesday and Thursday will resemble Monday with mostly sunny skies and mild temps.

The Rex block in the eastern Pacific begins to break down this week with the southern upper low sliding down the CA coast during the week. Models have been consistent in ejecting this upper low beginning on Thursday, which will bring the upper low across CO on Friday. Latest track brings the upper low to the CA/AZ/NV border on Friday morning and tracks it across western CO Friday evening and into western NE by Saturday morning. At the surface, this translates into increasing clouds into western CO late Thursday, with precip beginning early Friday. Precip intensifies west of the Divide Friday morning, with the snow level ranging from 8000 ft near the UT border, to 10,000 ft near the Divide. As the upper level trough tracks across CO on Friday, precip will move east into eastern CO Friday evening and night. However, the current track keeps the surface low north of I-70 as it moves across CO, so this means no upslope flow for the foothills and Plains. We may see some showers and isolated thunderstorms as the upper trough moves through, but precip amounts east of the Divide look pretty light, generally less than 0.10 to 0.25 inches, whereas precip west of the Divide should be between 0.50 and 1.00 inches. Snow level could dip to around 8000-9000 ft Friday night across the foothills, but do not expect any significant accumulations at this time. If the track of the upper level low/trough changes farther south, then we are talking an entirely different scenario, but as models have thus far been very consistent in the track, the above forecast seems likely at current time.

As system moves east on Saturday, some brisk westerly winds possible early Saturday, but becoming lighter and mostly sunny by afternoon, with temps near seasonal norms. Sunday should be mostly sunny, with a chance for showers across northern CO (north of I-70) Sunday afternoon/evening as a weak upper level trough passes to our north. Long range models indicate next week will remain mostly dry and mild across the state.
_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

Bump for Oct 10 update