Sunrise at our camp spot at Navajo Lake – pic taken 10/14/2022
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Saturday – 15 Oct 2022 – 11:00am
The past…
At Stevens Field the high yesterday was 68 and the low this morning was 32. The upper Piedra was 20 this morning and many spots were pretty close to the average low of 26. Humidity yesterday afternoon bottomed out at 17%. Winds at the airfield hit 10mph yesterday.
Precip summary… There has been no rain in the last few days and just a few small clouds.
Forecast discussion…
Clouds will increase tonight as a cut-off low is expected to move through NM Sunday and Monday. We’ll be on the northern edge, but we’ll see more clouds and scattered showers, especially on Sunday. The snow level will average around 10,000ft but we could see a few wet snowflakes in the valley tomorrow night. Snow will not stick in the valley but 1-2” is possible in the mountains.
Will it snow soon? I’m keeping an eye on a colder system expected around the 23rd. We could catch the tail end of a cold front, as the system skirts across northern Colorado. Right now forecast confidence is low. We’ll get a better a handle on the system as the data gets better. See the forecast meteograms below for a thorough weather geek explanation.
There was nothing significant on radar this morning.
My forecast…
This chart is read left to right with the most current time on the left. Times are in zulu. The top chart shows 24-hour precip amounts for 50 model runs of the Euro. The bottom chart shows the range of the amounts, the mean, and the control.
As more of the model runs in the top chart line up with each other, forecast confidence increases. Example: only 10 of the 50 model runs think we’ll get snow Sunday night, and those amounts range from 0.1” to 1.1”. My thoughts after looking at other products: We’ll be lucky to see any snowflakes Sunday night because it will be too warm.
Later in the period, starting around the 23rd, about half of the 50 model runs expect snow and amounts vary considerably. One model run even expects nearly 12” on the 26th.
To understand the chart, please look at the description above.
Starting with Sunday – 27 out of 30 model runs expect snow. That’s quite different than the Euro model above. The main reason: the GFS expects colder air leading to lower snow levels.
Do I buy it? Nope. Two reasons…
1. The source region for this system is subtropical – look at the satellite image above. Though it will draw in a little bit of cold air as it crosses NM, it will have little impact.
2. Model resolution. The GFS resolution is 0.5 degrees while the Euro is 0.2 degrees. 0.5 degrees is roughly 30 square miles, and 0.2 degrees is about 12 square miles. Imagine our terrain within 30 square miles vs within 12 square miles. It’s a big difference! 30 square miles includes many of our mountains while 12 miles doesn’t. This will give the GFS a “cold bias” in this situation, so I disagree with the GFS.
This difference in resolution is one of the reasons the Euro is often the better forecast model.
And later in the period? The GFS starts hinting at snow around the 22nd and is just as uncertain as the Euro.
And my thoughts after looking at other products for next week: Most of the cold air and precip will stay to our north. I see potential for a dusting of snow in the valley and a few inches in the mountains. Forecast confidence is low at this point.
Pagosa Springs historical data
| Average High | Record High / Year | Average Low | Record Low / Year |
| 64 | 82 / 1958 | 26 | 14 / 1966 |
Mark takes over tomorrow.
– Shawn
