Snow Hits Colorado 10/28-10/29 with Final Cold Front

Tomer’s Take: The current storm cycle ends with one final cold front that hits Colorado with the coldest air of the season and 8-24″ of snow accumulation. Strong jet dynamics and temperature efficiency will help generate the snow.

Colorado mountain temps dip below zero late 10/29 into 10/30.

Wyoming mountain temps dip below zero 10/28, 10/29, and 10/30.

Montana mountain temps dip below zero 10/27, 10/28, and 10/29.

Current Setup

Water vapor satellite shows the final cold front diving south through ID, MT, WY with light snow accumulation and a reinforcing shot of cold air. This front hits Colorado 10/28-10/29. It slows down and amplifies over the mountains.

Forecast Radar 10/28

Valid 10/28 10pm. Snow levels fall rapidly Saturday afternoon/night as colder air pours in. It’s all snow in Denver at 5280′.

Full Forecast Animation:

Forecast Jet Stream

Valid 10/28 11pm. Notice the trough over the Intermountain West supporting the final cold front and efficient upslope flow in Colorado’s mountains.

Forecast Snow

Mid-mountain valid 10/27-10/29.

Mid-Mountain Snow Forecast Timeline ->

Snowmass:

10/28: 10″+

10/29: AM 1-3″

Quandary Peak:

10/28: 8-12″

10/29: 2-6″

Gore Range:

10/28: 8-12″

10/29: 2-6″

Vail Mountain:

10/28: 8-12″

10/29: 2-6″

10/25 Update: Western Snow, CO Trending Up

Tomer’s Take: Two cold fronts remain on track to deliver snow and the coldest air of the season so far through 10/29. Snow totals in Colorado are trending higher 10/28-10/29.

Air temps in Colorado’s mountains drop below zero late 10/29 into 10/30.

Air temps in Wyoming’s mountains drop below zero 10/28, 10/29, 10/30.

My forecast video:

Snow continues at Timberline Lodge at Mount Hood, OR;

Current Setup

Water vapor satellite shows a large low pressure in the Pacific anchoring the pattern.

Storm System #1 is dropping south into the PNW.

Forecast Jet Stream

Forecast jet stream valid 10/28. Notice the trough and SW to NE orientation of the jet stream over CO.

Forecast Radar & Satellite

Bulk of snow accumulation in the Wasatch occurs on 10/26.

Bulk of snow accumulation in the Tetons occurs 10/25-10/26.

Bulk of snow accumulation in Colorado occurs 10/28-10/29.

Full Movie:

Forecast Snowfall

*Updated 2:30pm 10/25

10/25-10/27

*Updated 2:30pm 10/25

10/28-10/29

Trending Up in CO

Why are totals trending up? It’s a combination of the coldest air of the season increasing efficiency, powerful jet stream support and conditional symmetric instability (CSI), and slower frontal movement. If this trend holds then I would expect snow squalls.

Examples ->

Snowmass:

10/27: Late 1-3″

10/28: 8-12″

10/29: Early 1-2″

Quandary Peak:

10/28: 4-8″

10/29: 4-8″

Longs Peak:

10/28: 6-12″

10/29: 2-4″

Berthoud Pass, CO Air Temperature Forecast:

10/24 Update: Western Snow + Two Cold Fronts

Tomer’s Take: Two cold fronts deliver snow (10/24-10/29) and the coldest air of the season so far.

Colorado stays abnormally warm until late 10/27 then temps drop quickly. Below zero mountain temps likely on the morning of 10/30.

My forecast video:

Snow continues at Lake Louise Ski Resort, Banff.

Timeline

10/24-10/26: Cold front, Banff, PNW, Northern CA, ID, WY, MT, UT, CO.

10/27-10/29: Cold front, UT, WY, CO.

Current Setup

Water vapor satellite shows a big low in the Pacific anchoring the pattern.

Red/orange = drier air aloft.

Forecast Jet Stream

Forecast jet stream valid 10/28. Notice the big trough over the Intermountain West. This unlocks the coldest air of the season so far.

Forecast Rain/Snow Line

Wasatch Range, UT, (Min/Max Level):

10/24: 10500/11600

10/25: 10800/12100

10/26: 4400/9500

10/27: 5700/8400

10/28: 4300/6400

10/29: 4100/7100

Teton Range, WY:

10/24: 10500/11600

10/25: 10800/12100

10/26: 4400/9500

10/27: 5700/8400

10/28: 4300/6400

10/29: 4100/7100

Central Mountains, CO:

10/24: 11000/13800

10/25: 11000/14300

10/26: 10500/13800

10/27: 11000/13000

10/28: 6600/9500

10/29: 2500/7700

Forecast Radar & Satellite

Forecast Snowfall

(*Updated 2pm 10/24)

10/24-10/27:

(*Updated 2pm 10/24)

10/28-10/29:

10/23 Update: Western Snow + Three Cold Fronts

Tomer’s Take: The first of three cold fronts moves across the Banff, MT, WY today (10/23). The two remaining cold fronts are more significant 10/24-10/29 with additional jet stream support and colder air.

Colorado remains abnormally warm until 10/28 when the 3rd cold front arrives.

My forecast video:

Timeline

10/23: 1st Cold Front, Banff, MT, WY.

10/24-10/26: 2nd Cold Front, PNW, ID, MT, WY, Northern CA, UT, C+N CO.

10/27-10/29: 3rd Cold Front, WY, UT, CO.

Current Setup

Water vapor satellite shows a large area of low pressure lurking over the Pacific. It’ll help set the pattern with lobes of low pressure sliding down the jet stream from Canada across the West.

Red/orange = drier air aloft.

Forecast Jet Stream

Cold front #2: Forecast jet stream valid 10/25. Notice the dip in the jet over the PNW where an area of low pressure is digging south.

Cold front #3 dropping south.

Cold Front #3: Delivers a sharp drop in air temps.

Forecast Radar/Satellite

Forecast Rain/Snow Line

Wasatch, UT, (Min/Max Level):

10/23: 11200’/12000′

10/24: 10500’/11800′

10/25: 11300’/12100′

10/26: 7200/9500′

10/27: 6600’/8900′

10/28: 5900’/6900′

Central Mountains, CO:

10/23: 11600/14300

10/24: 11000/13900

10/25: 11300/14300

10/26: 9500/13500

10/27: 10500/13300

10/28: 9800/12600

Teton Range, WY:

10/23: 9800/10800

10/24: 8700/10200

10/25: 9200/10300

10/26: 2500/8400

10/27: 2600/6200

10/28: 2300/6100

Forecast Snowfall

*Afternoon Update 10/23.

10/23-10/27:

*Afternoon Update 10/23

10/28-10/29:

Examples

Teton Range, WY:

10/23: 1-2″

10/25: 4″

10/26: 8″

10/28: 1-3″

Alta/Snowbird, UT:

10/23: Trace R/S

10/26: 6-10″

10/27: PM 2″

10/28: 3-6″

Aspen/Snowmass, CO:

10/26: PM 1″ or less

10/27: PM 1″ or less

10/28: PM 1-2″

10/29: 4-8″

Western Snow Inbound with Three Cold Fronts 10/23-10/29

Tomer’s Take: An active week ahead with three separate cold fronts, 40 degree drop in air temps, strong wind, and heavy snow accumulation. Who’s affected? PNW, Banff, MT, ID, UT, WY, CO, CA.

Timing

Late 10/22 – 10/23: 1st Cold Front delivers snow to ID, WY, MT, Banff.

10/24-10/26: 2nd Cold Front delivers snow to PNW, ID, MT, WY, UT, Northern CA.

10/27-10/29: 3rd Cold Front delivers snow to CA, Southern ID, Southern MT, UT, WY, CO.

Current Setup

Notice the large, looming area of low pressure over the North Pacific. It’s a pattern changer and is accompanied by a large dip in the jet stream.

Forecast Jet Stream

Valid 10/25. Notice the dip in the PNW.

Valid 10/27:

Valid 10/29. The trough breaks loose and dives south spreading colder temps and snow accumulation through the Intermountain West. This is the best chance for snow in CO.

Forecast Radar & Satellite

Forecast Snow Totals

Mid-mountain totals 10/23-10/27. I added Red Lodge Ski Area, MT.

10/28-10/29:

Examples

Tetons:

10/23: 1-2″

10/25: 10″

10/26: 6″

10/28: 1-3″

10/29: 1-3″

Alta/Snowbird:

10/23: 1-2″

10/25: 1-3″

10/26: 3-6″+

10/27: 1″

10/28: 3-6″+

10/29: 1″

Aspen/Snowmass:

10/28: 1″

10/29: 4-12″

Mountain Weather Update 10/11: Snow for CO, UT, WY

Tomer’s Take: A storm system with snow for UT, WY, CO hits 10/11-10/12 along with a 15-30 degree temperature drop. The track of the storm continues trending slightly further north into WY. This has increased forecast totals for WY and parts of UT.

The mountain towns of Aspen and Vail start as rain then change to snow late 10/11 into 10/12.

The mountain town of Steamboat Springs stays mainly rain.

Full Forecast Video

Current Setup

Water vapor satellite shows the dipping jet and areas of low pressure lined-up. Red/orange = drier air aloft.

Forecast Jet Stream

Forecast jet stream velocities valid 10/12. Notice the dip in the jet supporting an area of low pressure. This is the first significant snow for the mountains of UT, WY, and CO.

Forecast Snow

*PM 10/11 updated forecast totals.

Forecast mid-mountain snow forecast valid 10/11-10/13.

Forecast Rain/Snow Line

Wasatch Mountains, UT

10/11: 9200’/7200′ (max/min)

10/12: 8200’/7200′

Central Mountains, CO

10/11: 13000’/9200′

10/12: 8400’/7100′

Teton Range, WY

10/11: 9000’/7900′

10/12: 8900’/8200′

Forecast High Peaks

Kings Peak, UT

10/11: 2-3″

10/12: 4-8″

Grand Teton, WY

10/11: 1-2″

10/12: 4-6″

Maroon Bells, CO

10/11: 3-6″

10/12: 4-6″

Mount of the Holy Cross, CO

10/11: PM 3-6″

10/12: 4-6″

Longs Peak, CO

10/11: PM 2-3″

10/12: 1-3″

Quandary Peak, CO

10/11: PM 1″

10/12: 2-4″

Forecast Radar

Cold Front with Snow CO, UT, WY 10/11-10/12

Tomer’s Take: A strong cold front with snow for CO, UT, WY is still on track between 10/11-10/12. Storm track has shifted a little north pulling the bigger CO totals a little further north. Light to moderate accumulation in UT, moderate in WY (exception is Hogadon Basin and Snowy Range with heavy snow coming), with moderate to heavy totals in the Central and Northern Mountains of CO. Air temps drop 15-30 degrees forcing snow levels to drop.

Mountain Towns

The mountain towns of Aspen and Vail, CO start as rain on PM 10/11 then change to a mix and then finally snow 10/12. Bulk of snow accumulation occurs at higher elevations.

The mountain town of Steamboat Springs, CO stays as rain both days.

Current Setup

Water vapor satellite shows the shifting storm track with penetrating Polar Jet and area of low pressure. Red/orange colors = drier air aloft.

Forecast Mid-Atmosphere

Below is forecast mid-atmospheric pressure anomalies valid 10/12. Notice the lower pressure anomalies over the CO, WY, UT.

Forecast Jet Stream

Below is forecast jet stream velocities valid 10/12. The Polar Jet delivers the cold front and area of low pressure.

Forecast Snowfall

*PM 10/10 Updated Snow Forecast Totals. I also put Hogadon Basin, WY on the map.

Forecast mid-mountain snow totals 10/10-10/13.

Forecast radar valid 10/12 10:15am:

High Peaks Forecast

Grand Teton, WY

10/10: PM 1-3 inches

10/11: 2-4 inches

10/12: 1-2 inches

Kings Peak, UT

10/11: 1-2″

10/12: 1″

Capitol Peak, CO

10/11: PM 1-3″

10/12: 3-6″

Longs Peak, CO

10/12: 3-6″

Quandary Peak, CO

10/11: PM 1-2″

10/12: 2-4″

Forecast Radar

Cold Front Delivers Snow to CO, UT, WY 10/11-10/12

Tomer’s Take: A dip in the jet stream delivers a strong cold front and area of low pressure to Colorado, Utah, and Wyoming between 10/11-10/12. Light accumulation in Utah and Wyoming. Heavier accumulation in Colorado (4-8″). Air temps drop 15-30 degrees.

The bulk of the snow accumulation in CO stays above 10,000ft in the Central and Northern Mountains, but snow accumulation is also possible between 8000-10,000ft at many mountain towns including Aspen and Vail where it will start as rain then change to snow. Steamboat Springs stays mostly rain.

Jet Stream

A buckling jet stream delivers colder air, falling snow levels, a strong cold front, and developing area of low pressure.

Below is forecast jet stream velocity valid early 10/12.

Moisture

Absolute moisture and relative humidities increase 10/11-10/12.

Below is forecast relative humidity at about 10,000ft. Saturation is likely from Denver vertically through the 14ers. Notice the highest moisture (darker colors) favor the Central and Northern Mountain zones.

Snow Forecast

Forecast snow accumulation. Notice the heaviest accumulation occurs in Colorado. The darkest blue band = 4-8 inches. Lightest blue band = 1-3″. Magenta = 6-12″+.

Forecast radar snapshot valid 10/12 at 6am. Full forecast radar loop is at bottom of post.

High Peaks Forecast

Grand Teton, WY

10/10: 1″ late

10/11: 1-3 inches

10/12: 1″

Kings Peak, UT

10/11: 1″ late

10/12: 1″ Early

Maroon Bells, CO

10/11: PM 1″

10/12: 6″+

Mount of the Holy Cross

10/11: PM 1-3″

10/12: 6″+

Longs Peak

10/11: 1″ late

10/12: 4-6 inches

Quandary Peak

10/11: 1″ or less

10/12: 2-6 inches

Forecast Radar

Winter Forecast 2023-2024

Tomer’s Take: A Strong El Nino is likely with a screaming Subtropical Jet across the Southern Tier by January, February, March, April, and May 2024. I believe we’ll see a 30% El Nino Modoki contribution. This puts several major ski resorts on ‘The Bubble’. Atmospheric River (AR) setups are likely along with large East Coast storm storm systems.

My full forecast video:

Pikes Peak Ascent, Run Rabbit Run, Next Colorado Snow Inbound 9/14-9/15

Tomer’s Take: It’s a busy weekend ahead for athletes with both the Pikes Peak Ascent/Marathon and Run Rabbit Run 50/100M. Both events will have weather impacts early in the weekend, drier later. I’m forecasting new snow accumulation above treeline on 9/14 and 9/15 with a cold front and active Subtropical Jet Stream.

Pikes Peak Summit

Snow accumulated on 9/10-9/11. I’m forecasting an additional 3-6 inches between 9/14-9/15.

LIVE summit cam 9/13:

Setup

Below is the forecast jet stream valid 9/14-9/15. Notice the active Subtropical jet and cold front merger.

Snow

Below is forecast snow accumulation between 9/13-9/15. The lightest blue shade is 1-3 inches with escalating values by color. Some mountain locations above treeline (above 13K in particular) could see 6″ or more.

Mountain & Event Forecast

Pikes Peak, Summit Level.

9/14: PM 1-2 inches snow,10-25mph gusts, 25/37F.

9/15: 2-4 inches snow, 10-25mph gusts, 25/28F.

9/16: AM dry, sun, PM flurries, 10-20mph gusts, 20/39F.

9/17: AM dry, sun, PM 40% rain/snow, 15-25mph gusts, 25/43F.

Run Rabbit Run, 10K Level.

9/14: 100% rain after 8am, 44F to 36F.

9/15: Overcast and valley fog, AM 20% rain/snow, PM 40% rain/snow, 35/43F.

9/16: Dry, sun, 37/52F.

Longs Peak, Summit Level.

9/14: PM 3-6 inches snow, 31F to 21F.

9/15: AM 1-3 inches snow, 20/24F.

9/16: Dry, sun, 21/35F.

Nolan’s Course, Summit Level.

9/14: PM 2-4 inches snow, 20/37F.

9/15: 1-4 inches snow, 23/31F.

9/16: Dry, sun, 19/42F.