12/9/21 Thursday 4:30 am
I learned early on that the most important thing a forecaster can do, before going to the computer, is to look outside. I refer to it as “Step 1”
I did that throughout the night. I saw wet pavement. Most areas around the forecast area are under a 100% saturated air mass.
Step 2-Look outside at other locations (webcams). I see light snow falling at Purgatory, Wolf Creek, Mancos Hill (flurries), and Hesperus Hill (flurries).
With 100% humidity and temperatures around 32 degrees, be careful of icy roads in spots out there this morning!
No new changes from the NWS overnight. They are leaving everything in place. They too are struggling with what to do with the lower and some mid-elevation areas in regards to snow totals. They mentioned that the models are showing winter storm warning snow totals for many areas between 6,500-to 7,500 feet. The problem is the temperature profiles early evening do not support accumulating snow. I will mention again what I said yesterday, heavy snow can actually cool the air and increase the snow to liquid ratio. This would make it more likely to see accumulating snow earlier than the temperature profiles suggest.
For now, they left the WSW (winter storm watch) in place for the lower elevations. They have not changed the winter storm warning above 8,500 feet for 1 to 2 feet.
Pueblo NWS further decreased the amounts for Wolf Creek to 10-20 inches. Big, big, mistake. I hope CDOT is not relying on that info…
An Avalanche Watch was issued yesterday afternoon for the high country.
BULLETIN – IMMEDIATE BROADCAST REQUESTED
COLORADO AVALANCHE INFORMATION CENTER
RELAYED BY NATIONAL WEATHER SERVICE DENVER/BOULDER CO
259 PM MST WED DEC 08 2021
THE FOLLOWING MESSAGE IS TRANSMITTED AT THE REQUEST OF THE
COLORADO AVALANCHE INFORMATION CENTER.
* WHAT…Avalanche Watch
* WHERE… CAIC Forecast Zones- Steamboat/Flat Tops, Aspen,
Gunnison, North San Juan, South San Juan
* WHEN… Very dangerous avalanche conditions are expected from
Thursday evening December 9 through Friday December 10
* IMPACTS…A large storm moving into Colorado will rapidly increase
the avalanche danger. Very dangerous conditions will develop by
Thursday evening. A natural avalanche cycle is expected. Northerly-
facing slopes are the most dangerous. Travel in avalanche terrain
is not recommended from Thursday evening through Friday.
* PRECAUTIONARY/PREPAREDNESS ACTIONS…Travel in avalanche terrain
is not recommended from Thursday evening through Friday. Go to
http://www.colorado.gov/avalanche for the most up-to-date information.
The models are locked onto this system.
Here are the latest forecasts for liquid-equivalent precipitation in inches
NDFD NOAA high-resoluti0n blended
NAM 3km high-resolution operational
Oh Canada! Canadian model
Point forecasts will underplay this storm. Some are going to be right, but some are going to be a big miss. NOAA will adjust them as changes occur. If you are an app user, your forecasts will lag what is happening and will also fluctuate. Especially in the lower and mid-elevations.
I will update again around 9 am after the new GFS and the high-resolution models update. Thanks for following and supporting the site!