Big Totals Through 2/29

Tomer’s Take: The main trough of low pressure hitting CA breaks loose tonight and slides through UT/CO 2/21-2/22. The pattern shifts on/after 2/25 when the Northern Jet Branch buckles south and merges with the Subtropical Jet. Big totals likely.

Timing

*4:30PM 2/20 Update.

CA 3-6″ Tonight – AM 2/21.

Wasatch 8-16″ Next 24 Hours.

Tetons 1-2″ 2/22.

Colorado 1-4″ Next 48 Hours.

Northern Branch Merger 2/25-2/29, WNW Flow.

Northeast Light/Moderate Snow 2/23, 2/27-2/28.

My afternoon forecast video update:

Current Setup

Water vapor satellite shows the large trough of low pressure hitting CA then breaking loose and moving through UT/CO 2/21-2/22.

The second area of low pressure in the Gulf of Alaska sends a small piece of energy south into CA while the main trough slides into AK/Canada then south into the United States with a buckling Northern Branch.

Orange/red = drier air aloft.

Forecast Jet Stream

Forecast Radar & Satellite

Forecast Totals

Grand totals by late 2/29.

Feet Of Snow Through 2/28

Tomer’s Take: Heavy snow accumulation hits UT PM 2/19-2/21. Light to moderate snow accumulation for the Tetons PM 2/19-2/20. Colorado gets light snow accumulation 2/20 and moderate snow 2/22. California continues to receive heavy snow accumulation now through 2/20. Then the pattern shifts on/after 2/25 with the Northern Jet Branch buckling, merging with the Southern Branch, a preferred NW Flow, and additional energy delivery. Big widespread totals likely. If this spills into early March then it’ll be a solid start.

My mountain weather update video:

Current Setup

Water vapor satellite shows a large trough of low pressure hitting CA. It’s sending waves of snow into the interior Rockies. The entire storm system breaks loose 2/20-2/22 through UT/WY/ID/CO.

The area of low pressure in the North Pacific will become part of the 2/25-2/28 Northern Branch setup.

Orange/red = drier air aloft.

Forecast Jet Stream

Forecast Radar & Satellite

Forecast Totals

Grand Totals by late 2/28.

The Week Ahead

Tomer’s Take: Snow in the Wasatch and Colorado ends tonight with another 1-3 inches in the Tetons. The next storm system arrives 2/19-2/22 in UT/CO/ID/WY with moderate to heavy snow accumulation. Big totals possible 2/25-2/28 with northern jet involvement and energy.

My afternoon forecast video update:

Current Setup

Water vapor satellite shows a large trough of low pressure sending waves of energy into the Intermountain West. The entire trough moves into CA 2/19-2/20 with heavy snow accumulation across the Sierra. Then it hits UT/ID/WY/CO 2/20-2/22.

Orange/red = drier air aloft.

Forecast Jet Stream

Forecast Radar & Satellite

Forecast Totals

Grand totals by late 2/27.

Northeast:

VT/NH/ME light snow accumulation PM 2/22-2/23. Another storm system around 2/27.

Fading El Nino

BTW, EL Nino is fading quickly. We’re officially under a “La Nina Watch”. Neutral conditions by May and La Nina by Summer.

This will slowly shift the pattern for the Western United States. I think we’ll still have a solid March across UT/ID/WY/CO.

Colder values represent La Nina.

Major Snow Ahead

Tomer’s Take: Moderate snow accumulation hits Tahoe & Mammoth tonight into early 2/18. A wave of light snow accumulation overspreads UT/WY/CO on 2/18. A major storm system delivers 1-2 feet of accumulation in the Sierra 2/19-2/20. This same storm system then hits the Wasatch with 1-2 feet (or more) 2/19-2/21, and Colorado’s Central & Northern Mountain Zones with 6-12 inches 2/21-2/22.

On/after 2/25 the Northern Branch gets involved and significant snow is possible.

My afternoon forecast video update:

Current Setup

Water vapor satellite shows three different areas of low pressure. The 2nd storm system is associated with the primary trough in the atmosphere. This is the 2/19-2/22 storm system.

Orange/red = drier air aloft.

Forecast Jet Stream

Forecast Radar & Satellite

Forecast Totals

2/25-2/28: Dynamic period with Northern Branch involvement. Significant snow is likely with this setup and colder air.

Powder Weekend

Tomer’s Take: It’s a powder Friday and a powder weekend with additional snow accumulation likely in ID/UT/WY/CO. A trough of low pressure approaching the West Coast is sending ripples of energy into the Intermountain West generating snow accumulation.

Snow Timeline

Wasatch 4-6″ Today, 4-6″ 2/18.

Tetons 4-5″ Today, 3-5″ 2/18.

Colorado 2-8″ Today/Tonight, 1-2″ 2/18.

Northeast Light Snow 2/17, 2/18.

My afternoon forecast video update:

Current Setup

Water vapor satellite shows the approaching trough sending ripples of energy into the Intermountain West generating snow accumulation.

Orange/red = drier air aloft.

Forecast Jet Stream

Forecast Radar & Satellite

Forecast Totals

Northeast:

Snow: Light 2/17, 2/18.

Powder Day! Snow Forecast Next 48 hours & Beyond

Tomer’s Take: The Teton snow bullseye continues next 48 hours with another 12-14 inches. That’ll be three feet in three days. I’m forecasting 6-8 inches today (2/15) across the Wasatch. In Colorado, I’m forecasting 4-8 inches across the Central and Northern Mountain zones 2/15-2/16.

My afternoon forecast video update:

Current Setup

Water vapor satellte shows the current storm system generating snow in UT/WY/CO/ID.

The larger trough of low pressure over the Pacific will move at snails pace sending ripples of energy into the Intermountain West through 2/22.

Orange/red = drier air aloft.

Forecast Jet Stream

Forecast Radar & Satellite

Forecast Totals

Northeast:

Snow: PM 2/15-2/16.

Snow forecast through 2/23

Tomer’s Take: Storm systems hit the West Coast through 2/23 and pieces break off and hit UT/ID/MT/UT/CO. There are a few snow bullseyes including the Tetons, Sierra, NW Colorado, and Wasatch with feet of grand total accumulation.

My afternoon forecast video update:

Jackson Hole is reporting 16″ in 24 hours. I’m forecasting another 2 feet (at least) through 2/23.

Snow Timeline

Tetons: Now-2/16, 2/18-2/20.

Sierra: PM 2/14 – AM 2/15, 2/17 – AM 2/18, 2/19-2/20.

NW CO: PM 2/14-2/16, PM 2/18, 2/21.

Wasatch: 2/15, 2/18, 2/19-2/21.

Current Setup

Water vapor satellite shows a few different storm systems lined-up for the West.

Orange/red = drier air aloft.

Forecast Jet Stream

Forecast Radar & Satellite

Forecast Totals

Grand totals 2/14-2/23.

Northeast:

Snow: PM 2/15 – AM 2/16, 2/23.

Sierra & Teton Snow Bullseyes

Tomer’s Take: The pattern favors two distinct snow bullseyes through 2/22: Sierra & Tetons with feet of grand total accumulation.

Overall, it’s a pattern dominated by storm systems hitting the West Coast then weakening and sending pieces of energy/precip into the Intermountain West.

My afternoon forecast update video:

Snow Timeline

Tetons: Now-2/16, 2/18-2/20.

Wasatch: 2/14 (light), 2/15, 2/18, 2/20, 2/22.

Colorado C+N Zones: 2/14 – AM 2/17, 2/18-2/19, 2/20, 2/22.

Sierra: PM 2/14 – AM 2/15, 2/17 – AM 2/18, PM 2/18-2/19.

Current Setup

Water vapor satellite shows four different storm systems over the Pacific.

Orange/red = drier air aloft.

Forecast Atmospheric River

Forecast Integrated Vapor Transport (IVT) valid near the San Francisco coast (38N/123W) shows low-level/weak atmospheric river (AR) contribution with each storm system.

Forecast Jet Stream

Forecast Radar & Satellite

Forecast Totals

Shifting Pattern and Snow Bullseye For Tetons

Tomer’s Take: The pattern 2/12-2/15 favors PNW/BC/ID/MT/WY. Then the stormtrack shifts south 2/16-2/22 to favor CA/OR/UT/ID/WY/CO. The overlap between both periods is the Teton Range, WY where I’m forecasting 2-3 feet of grand total accumulation. Overall, the pattern continues trending weaker for most locations. What once looked like a major initial storm system 2/15-2/17 now looks weak/fast/ragged.

In the Northeast, the 2/13 storm system continues shifting south, and that pulls snow accumulation out of VT/NH/ME.

Next storm system arrives late 2/15-2/16.

My afternoon forecast video update:

Current Setup

Water vapor satellite shows a trio of storm systems traversing the North Pacific.

Orange/red = drier air aloft.

Forecast Jet Stream

Forecast Radar & Satellite

Forecast Totals

Teton snow: 2/13 – AM 2/16, 2/18-2/20.

Wasatch snow: 2/15, 2/18-2/19.

CO Snow C+N Zones: PM 2/15-2/16, 2/18, 2/20.

Sierra snow: PM 2/14 – AM 2/15, 2/17-2/19.

VT/NH/ME snow: Late 2/15-2/16.

The Week Ahead

Tomer’s Take: The stormtrack now favors the PNW/BC/ID/MT/WY through 2/15. Then it shifts south 2/16-2/21 to favor CA/UT/ID/WY/CO. The initial storm system is trending weaker/faster, but additional waves of moisture get pushed through the interior Rockies by a strong Subtropical jet.

The Northeast gets moderate to heavy snow 2/13 and 2/16. 2/13 stormtrack is trending a little further south.

My afternoon forecast update video:

Current Setup

Water vapor satellite shows a trio of storm systems over the North Pacific. The first two affect the PNW/BC/Northern Tier, and the third is part of the pattern shift after 2/15.

Orange/red = drier air aloft.

Forecast Jet Stream

Forecast Radar & Satellite

Forecast Totals

Teton snow: 2/13-2/15, 2/18, 2/20.

UT snow: 2/15-2/16, 2/18, 2/20-2/21.

CO snow: PM 2/15-2/16, 2/18, 2/21.

Northeast:

2/13 storm system mainly delivers snow to southern VT, southern NH, southern NY, southern ME, MA.

Late 2/15-2/16 delivers snow to most of VT/NH/ME.