The mid-atmosphere pressure pattern favors the Pacific Northwest/West Coast for above normal precipitation. In Colorado, we’ll get leftovers with high pressure regulating most days.
Forecast October grand totals are below. Best accumulation is at higher elevations in these locations. Normally, this snow falls then melts except on the higher peaks. Also, strong wind starts kicking-in with these stormy periods.
Fall Color Update
Peak Fall Color is running behind schedule in Colorado. Parts of the mountains saw a robust Monsoon season.
Jennifer Broome snapped this photo on 9/22 in Vail:
Some zones like Grand Lake, Berthoud Pass, RMNP, and the Northern Mountains are further along.
John Williams snapped these photos between 9/21-9/22:
Abnormally warm and dry Fall season across the West.
Late start to Winter.
Large Western ridge of high pressure September 2022 – March 2023.
Overall, target PNW, British Columbia, Banff Area, Wyoming, Idaho, and Montana for most consistent winter snowfall.
Two big unknowns: Warm SST’s North Pacific and underestimation of La Nina strength this Fall and early Winter. Both could complicate the Winter storm track and snowfall pattern(s).
Winter Forecast Video
Video contains my entire forecast.
Triple-dip La Nina
What is La Nina? Colder than normal (-0.5C or colder) sea surface temperatures in the Equatorial South Pacific (see graphic below). El Nino is the opposite (+0.5C or warmer). Both anomalies have global implications on weather and climate.
Currently, sea surface temperatures near the equator are running colder than normal for the third straight year. Triple-dip La Nina’s are rare only occurring three times in the last 73 years.
Here’s the global sea surface temperature anomalies valid 8/29/2022. Red/orange = above normal. Blue = below normal.
Notice the sea surface heat wave in the North Pacific and North Atlantic.
The Multivariate ENSO Index (MEI) factors in five different variables and assigns a value. It’s currently the strongest (coldest, negative) value since 2010. It says this dip is the strongest of the three dips so far.
Strongest triple-dip La Nina since 2010:
Sea surface temperatures are abnormally warm in the North Pacific (off the PNW/B.C. coast and California coast). This directly affects the storm track and precipitation patterns. Will this continue all winter?
This is where important uncertainty remains in the forecast.
I believe the water off the PNW coast stays abnormally warm through November then cools-off in December. Some forecast data suggest this water does not cool-off and the PNW stays abnormally dry.
The result: warm and dry across most of the Intermountain West through November then snowier/colder weather settles in December-March.
I believe the water off the California coast stays abnormally warm the entire winter. The result: warmer and drier than normal winter.
Warm and Dry Fall Season
Most of the Intermountain West is in for an abnormally warm and dry September, October, and November. It will mirror the last few years with a large Western ridge of high pressure.
Said another way, it’ll be a late start to winter.
The most consistent snow and cold temps arrive in December as the jet stream finally dips south.
I agree with the official NOAA ENSO forecast, which maintains high chances for La Nina through Fall (blue bars) then it fades in January 2023 to Neutral phase (gray bars).
Important note: It’s possible some forecast data is underestimating the strength of La Nina this Fall and early Winter.
The latest ensemble forecast spread from the Climate Forecast System shows a strong Fall La Nina that fades early 2023.
My big picture pattern forecast. Notice the large Western ridge of high pressure.
All other forecast specifics are in the Winter Forecast Video at the top of this page.
Andrea Sansone set new supported woman’s Fastest Known Time (FKT) on the Nolan’s14 course going south to north in 45:52 between 9/10-9/11.
Prior supported woman’s FKT (10/3/2020): Sabrina Stanley 48:49.
The overall FKT is held by Joey Campanelli at 41:00 on 7/2/2020.
Nolan’s requires athletes complete fourteen 14ers in less than 60 hours. This equates to about 100 miles of distance and 44,000ft of climbing in the Sawatch mountain range between Salida and Leadville.
Sansone also holds the overall FKT for most 14ers in 24 hours.
“This was the hardest yet most rewarding accomplishment I’ve experienced so far, and an impossible feat without my crew. I’ve never been pushed so hard by an incredible group of athletes – they wanted this for me as much as I wanted it. It was their dedication and incredible effort that made this attempt successful.” – Andrea Sansone
A few weeks ago I received a text from Andrea. I love getting these because they normally include some ambitious future project!
Fast forward to last week and it was game-on for Nolans14 FKT. I was hooked. Then the wildfire smoke and two cold fronts started showing up in my morning weather analysis. Normally, September is dead quiet after the Monsoon. But, in recent years wildfire smoke has become commonplace.
According to Andrea, this was a crux moment (possibly the crux moment):
“It was pretty incredible how miserable I was, that we seem to almost immediately forget the pain. Andrew told me I could quite (I was so close to making that call…) but I would regret it about 3 hours later when I was feeling better.”
Double trouble. Two low pressure systems lined-up for Colorado. Water vapor satellite. Red/orange = drier air aloft.
Pikes Peak and Run Rabbit Run
By the time we get to the weekend, a very Fall-like pattern establishes itself. A jet streak arrives and delivers a few different cold fronts that brush the Northern Mountains. Wind and scattered rain/snow showers possible.