Tomer’s Take: I’m forecasting three more atmospheric river (AR) surges through 1/15. Beyond 1/15 the atmospheric river is much weaker and fading.
Snow levels will run high 1/7-1/10. Best Sierra snow stays above 7,000ft.
Alta, UT is reporting 11″ in the last 24 hours. The pushes them up to 319″ for the season.
Alta, UT 1/6/2023.
Current Setup
Infrared satellite shows a busy Pacific storm track with atmospheric river contribution. The powerhouse low pressure from 1/4-1/5 still spinning off the coast. The other low pressure’s will rotate around it like spokes on a wheel.
Forecast Pattern
Forecast jet stream valid 1/6-1/11. The jet pattern much less supportive of AR activity. It’s more amplified with definite troughs and ridging.
Atmospheric River
Below is the ECMWF IVT 16-day forecast by latitude. I marked the next three surges.
Tomer’s Take: A monster storm system loaded with atmospheric river (AR) continues today in CA, WA, OR with 100mph wind and high snow levels. Part of that moisture then moves into the interior Rockies including NV, UT, ID, WY, and CO. There are three additional weak to moderate intensity AR surges through 1/14.
My afternoon video update 1/5:
It continues to snow very hard at Mammoth Mountain with more accumulation likely. 7am cam view:
Current Setup
Water vapor satellite shows the big low pressure system nailing the West Coast. It represents a moderate to strong AR surge. 100mph wind and high snow levels are present in the Sierra.
Orange/red = drier air aloft.
Atmospheric River
Below is the GEFS model IVT forecast by latitude. There are three additional weak to moderate AR surges through 1/14. The current storm system is the largest AR surge of them all – look at the brighter colors (pink/purple/red).
Tomer’s Take: I’m forecasting four moderate atmospheric river surges through 1/13. Primary beneficiaries are CA, OR, WA, BC. Snow is also likely through the interior Rockies.
My forecast video 1/4:
Current Setup
Visible satellite shows a monster area of low pressure hitting the West Coast with a firehose of moisture. Notice how well-defined the area of low pressure is – the spiral is photogenic.
Forecast Pattern
Forecast jet stream valid 1/13.
Atmospheric River
Below is the GEFS IVT forecast by latitude out 16 days. The brighter colors (yellow/orange/red) represent larger surges. There are moderate AR surges on 1/4-1/5, 1/7-1/8, 1/9-1/10, and 1/13.
Forecast Timing
Forecast radar/satellite valid 1/4-1/9.
Forecast Totals
Forecast snow totals (inches) valid 1/4-1/6.
By request, I added Eldora, CO to the maps going forward.
Tomer’s Take: I’m tracking three moderate intensity atmospheric river (AR) surges through 1/12. Biggest totals occur in CA, WA, OR, BC.
Current Setup
Infrared satellite shows the Pineapple Express and low pressure systems lined-up.
Forecast Pattern
Forecast jet stream valid 1/12 shows a choppy jet stream with well-defined dips and ridges. This pattern favors the West Coast for biggest snow totals with less through the interior Rockies.
Atmospheric River
The latest GEFS IVT forecast by latitude shows three additional moderate intensity AR surges through 1/12. Beyond, there are weaker AR surges through 1/19. The surges occur 1/4-1/5, 1/8, 1/10.
I continue to worry about catastrophic flooding at the lower elevations of Northern California through 1/12 with potentially 15-20 inches of additional rainfall.
Forecast Timing
Forecast radar/satellite valid 1/3-1/8.
Forecast totals
Forecast snow totals (inches) valid 1/3-1/5.
Forecast snow totals (inches) valid 1/6-1/12.
Forecast snow totals (inches) valid 1/3-1/12. The bulk of this snow occurs 1/4-1/5 and with a possible coastal storm system on/about 1/12.
Tomer’s Take: The atmospheric river (AR) continues through 1/11 with the biggest impacts in CA, WA, OR. A moderate intensity AR surge occurs in CA 1/4-1/5. This storm impacts UT, WY, ID, CO on 1/5-1/6. There appears to be another moderate intensity AR surge for CA/West Coast on/around 1/10.
7-Day Totals:
Brighton, UT is reporting 80 inches in the last 7 days.
Kirkwood, CA is reporting 74 inches in the last 7 days.
Alta, UT is reporting about 69 inches in the last 7 days.
Palisades Tahoe, CA is reporting 69 inches in the last 7 days.
Wolf Creek, CO is reporting 42 inches in the last 7 days.
Steamboat, CO is reporting 35 inches in the last 7 days.
Alta, UT has officially surpassed 300″ for the season so far.
The morning view at Palisades Tahoe before the next AR surge on 1/4-1/5.
My forecast video 1/2:
Current Setup
Infrared satellite shows the Pineapple Express flow with areas of low pressure lined-up. The big low in the northern Pacific (north of HI) hits CA/West Coast 1/4-1/5 with moderate level AR intensity.
Forecast Pattern
Forecast jet stream valid 1/11. The flow continues to favor CA, WA, OR for biggest AR impact. The jet is choppy for the interior Rockies with less snow accumulation.
Atmospheric River
The long term forecast for AR is below from the GEFS model. You’re looking at forecast IVT plumes/transport across latitudes. It includes two more moderate intensity surges for CA, WA, OR. These are represented by the brighter colors (yellows, oranges, reds). The first is 1/4-1/5. The second is on/around 1/10. The AR surges beyond 1/10 are not as robust but could still be weak intensity AR surges. Bottom line, the above average precipitation continues for the West Coast beyond 1/10.
I worry about catastrophic flooding in the Northern California.
Tomer’s Take: 2023 features a continuation of the atmospheric river through 1/9. A moderate level intensity moisture surge occurs on 1/4-1/5 in CA, OR, WA. The jet becomes choppy through UT, WY, and CO on/after 1/4 with some ridge stress cutting down on snow totals.
My forecast video 1/1:
Current Setup
Infrared satellite shows the Pineapple Express and low pressure systems lined-up. The big low in the north Pacific hits the west coast 1/4-1/5.
Forecast Pattern
Forecast jet stream valid 1/10. Notice how choppy the jet becomes with some ridge stress through UT, WY, CO.
Tomer’s Take: The atmospheric river (AR) continues through 1/9, but the storm systems weaken 1/3-1/9 once they move into UT, CO, NM. Snow levels remain elevated in the Sierra because of this warm, moist AR. They’re also elevated on 12/31 in the Wasatch with rain reported at the base of Park City. Snow levels should gradually fall on Sunday 1/1 at Park City as slightly colder air filters in.
My forecast video 12/31:
Steamboat received 8 inches in the last 24 hours. That puts them at 188″ for the season. It’s their snowiest December in a decade. And more snow is on the way through 1/9.
8am 12/31/2022.
Current Setup
Infrared satellite shows the rich flow of moisture and areas of low pressure lined-up.
Forecast Pattern
Forecast jet pattern valid 1/9. Notice the pattern turns more amplified with well-defined troughs of low pressure. This places more ridging stress on the Intermountain West with weaker shots of snow 1/3-1/9 through UT, CO, NM.
Forecast Timing
Forecast radar/satellite valid 12/31-1/4.
Forecast Totals
Forecast snow totals (inches) valid 12/31-1/2.
Forecast snow totals (inches) valid 1/3-1/9.
Forecast grand totals 12/31-1/9. Central and Northern Mountains of Colorado:
Tomer’s Take: The atmospheric river now looks to continue through 1/8. Feet of additional snow accumulation likely in CA, UT, WY, CO. But, the 2nd period appears to generate less snow for UT than previous updates.
My forecast video 12/30:
Current Setup
Infrared satellite shows the Pineapple Express and parade of low pressure systems lined-up through 1/8.
Forecast Pattern
Forecast jet stream valid 1/8. The west-to-east orientation continues to act like a conveyor belt for moisture transport into the Western United States.
Moab-Grand Canyon
Per request, here’s what I see for the Moab-Grand Canyon area January 1-7, 2022.
Moab
GC
1/1
100% Rain, 47/38, Gusty
100% Mix, 40/33, Gusty
1/2
90% Mix, 38/32
50% Snow, 31/25
1/3
30% Snow, 34/29
90% Snow, 29/23
1/4
20% Snow, 34/26
30% Snow, 30/20
1/5
30% Snow, 35/26
40% Snow, 33/20
1/6
30% Snow, 36/29
30% Snow, 33/22
1/7
20% Snow, 34/27
20% Snow, 34/21
Forecast Timing
Forecast radar/satellite valid 12/30-1/3.
Forecast Totals
Forecast snow totals (inches) valid 12/30-1/1.
Forecast snow totals (inches) valid 1/2-1/8. The Wasatch totals for this period have decreased. A storm system on 1/5-1/6 is weaker after departing CA. And, a storm system on 1/7-1/8 also appears weaker after departing CA.
Tomer’s Take: It now looks like the atmospheric river (AR) continues through 1/6 generating feet of grand total snow across the West.
Awesome sunrise view at Palisades Tahoe this morning in-between storm systems.
The first storm system delivered 13-22 inches of snow at higher elevations with a rain/snow problem lower.
My forecast video 12/28:
Current Setup
Infrared satellite shows the Pineapple Express. The initial low pressure systems is tracking through the Intermountain West. All other waves of moisture will follow its lead.
Forecast Pattern
Forecast jet stream valid 1/5 shows the powerful west to east jet stream acting like a conveyor belt for Pacific moisture.
