You know it’s been a good winter when you need snowshoes to do your CoCoRaHS reports!
If images fail to load in the email, please click the title of the post. Thanks!
Thursday – 9 Mar 2023 – 4:45pm
The past…
At Stevens Field the high temp this afternoon was 46. The low this morning was 21. Winds at the airfield peaked at 13mph.
| Average High | Record High / Year | Average Low | Record Low / Year |
| 48 | 67 / 1972 | 13 | -10 / 1964 |
Precipitation summary… There was no measurable precip in the last 24 hours.
Forecast discussion…
Rest of today… Zonal west to east upper level flow will continue to push patches of mid and high clouds through the area.
Temps… Lows tonight will be in the low teens to low 20s.
Winds… Winds will be less than 10mph overnight.
Friday through Sunday… We are going to catch a piece of an “atmospheric river” event. A deep subtropical moisture plume will move west to east across the region.
A few key points: 1. Warmer air will move in making it a sloppy rain/snow mix in the valley. 2. Upper level westerly flow does not favor us. 3. It’s interesting to me that there won’t be much storm energy. Divergent winds aloft will aid lifting, but it’s mostly just deep moisture that will be rapidly lifted over our mountains.
Hit and miss showers are possible Friday afternoon to Sunday afternoon. The best chance for precip is Friday evening through Saturday afternoon. A stray thunderstorm or two is also possible Saturday and Sunday afternoons. Warmer air will limit snow in the valley. Our mountains above 9,000ft will do pretty good, but the northwest San Juans, Grand Mesa, and Elk Mountains will be favored.
Temps… Friday through Sunday highs will be in the low to high 40s. Friday and Saturday lows will be in the high 20s to mid-30s. Lows Sunday will be in the low 20s to low 30s.
Winds… Winds Friday and Sunday afternoons will peak in the 15-20mph range. Winds Saturday will peak in the 20-25mph range.
Snow levels…
Snow levels will rise to 8,000ft by Friday afternoon and will continue to rise to over 8,500ft by Friday evening. They’ll stay over 8,500ft into Saturday evening and then lower to around 7,500ft Saturday night.
Precip amounts…
Valley below 8,000ft: 0.40” to 0.70” of rain with up to a half inch of slushy snow
Valley above 8,000ft: 0.60” to 1.00” of rain and 1-3” of slushy snow
Mountains above 9,000ft: 12-24”
*** A half inch of rain and temps above freezing will melt snow in the valley and could lead to minor flooding in low-lying areas. It’s going to be a sloppy mess! ***
*** The Grand Junction NWS has issued a WINTER STORM WARNING for the southwest San Juan Mountains for elevations above 8,000ft. 10-20” of snow with up to 30” is possible along with winds to 60mph. valid 11am Friday to 6am Sunday. *** I expect much less snow here in the valley above 8,000ft.
This is the Euro forecast model valid at 8am Saturday morning.
Upper left is wind at ~30,000ft. There is a weak branch of the jet stream to our north over northern WY and a stronger branch just to our south. Between the two is divergent wind flow which aids in lifting. Flow over Archuleta County at 30,000ft is generally west to east and speeds are around 90kts with 110kts just to our south.
Upper right is moisture and general flow at ~18,000ft. Moisture is indicated by green colors. I highlighted the “atmospheric river” band in dark green. General flow is west to east.
Bottom left is precipitable water percent of average. This time of year anything over 140% can be significant. At 8am Saturday all of Archuleta County is over 200% of average. Note how the above average precipitable water lines up with the moisture in the upper right panel.
Bottom right is 6-hour precip Saturday morning. This lines up pretty good with the other panels.
Monday through Tuesday evening… Transient ridging will dry us out a bit but spotty showers are possible, mostly over the mountains.
Temps… Highs will be in the mid-40s to low 50s and lows will be in the high teens to high 20s.
Winds… Afternoon winds will peak around 15mph.
Tuesday night and beyond… Another system is taking shape roughly Tuesday night into Friday morning. And beyond that, it looks like the pattern will stay active through the 8-14 day period.
My next post will be tomorrow.
– Shawn
