Tomer’s Take: Major storm cycle lasts until 2/10. A storm system continues to spin in CA with heavy rain and Sierra snow. A powerful Subtropical jet is transporting moisture ahead of this storm system on 2/5 into UT/ID/WY/MT and into CO/NM on 2/6. Smaller pieces of energy will dive into the intermountain west behind this storm and keep the snow going through 2/8-2/10.

My afternoon forecast video update:

Current Setup

Radar shows the main storm system spinning in CA. Powerful transport jet wind carries moisture into UT/ID/WY/MT.

Flash flooding continues in Southern CA. Almost a foot of rain in places from a rich AR surge, storm system, and powerful Subtropical jet flow.

Precipitable water (PWAT) valid early 2/5. This is a measure of moisture in the atmosphere. Notice the green/lime plume (or finger) of higher PWAT values pointing directly at Southern California. This is a signature of the atmospheric river (AR) and it enhances precipitation.

Forecast Jet Stream

CA storm system and trough starts to move into the interior Rockies.

Broad trough, storm system and smaller pieces of energy roll through UT/WY/ID/AZ/CO/NM.

Forecast Radar & Satellite

Forecast Totals

CO Snow: 2/6-2/10, 2/14.

UT Snow: 2/5-2/9.

WY Snow: 2/5-2/8, 2/13.

Revelstoke Snow: 2/6-2/8, 2/12-2/13.

VT/NH/ME Snow: 2/9-2/10 (Light), 2/12-2/13.

Tomer’s Take: Current storm cycle lasts through 2/12 then high pressure builds. Next storm system is hitting CA with a moderate/strong atmospheric river (AR) surge 2/4-2/5. Then this storm system breaks loose 2/5-2/8 and hits UT/ID/WY/MT/CO/NM with heavy snow accumulation. A smaller storm system 2/8-2/9 races into UT/AZ/CO/NM and meshes with the prior storm system and keeps the snow going. Another small storm system 2/10-2/12 takes a northern track and moves through BC/MT/ID/WY/UT/CO with light to moderate snow accumulation.

My afternoon forecast video update:

Current Setup

Major storm system with a moderate/strong AR surge continues in California 2/4-2/5. Then this storm system breaks loose 2/5-2/8 and hits UT/ID/WY/MT/CO/NM.

Central CA Radar 2/4 at 3:45pm:

Water vapor satellite shows the storm system off the CA coast. The other storm system will curve into AK/Canada and eventually send energy south into the United States.

Orange/red = drier air aloft.

Forecast Jet Stream

Powerful moisture transport into CA and optimized Subtropical jet stream orientation.

Storm system(s) and trough sliding through the Rockies with heavy snow accumulation.

Storm system and remaining trough exiting CO/NM. Small storm system in BC races southeast into Northern Tier.

Forecast Radar & Satellite

Forecast Totals

UT Snow: 2/5-2/9, 2/12.

CO Snow: 2/6-2/10, 2/12.

WY Snow: 2/5-2/8, 2/10-2/11.

Revelstoke Snow: 2/4, 2/6, 2/8-2/9, 2/11.

VT/NH/ME Snow: 2/10, 2/12-2/13.

Tomer’s Take: Heavy snow continues in the Sierra with storm #1. This storm then moves into UT/WY/ID/MT/CO/NM through 2/4. A Panhandle Hooker storm system develops near the TX/OK panhandles on 2/3. This storm system enhances snowfall totals across parts of CO and NM. Storm #2 delivers a moderate intensity atmospheric river (AR) surge to CA 2/4-2/5. This storm then moves into UT/ID/WY/MT/CO through 2/8. Big grand totals likely measured in feet in CA/UT/WY/CO.

My afternoon forecast video update:

Current Setup

Water vapor satellite shows three different storm systems lined-up in the Pacific riding a powerful Subtropical jet stream.

Red/orange = drier air aloft.

Old Man Winter Rally 2/4

Event takes place in Lyons, CO on 2/4.

2/2: Increasing clouds, rain to snow after 10pm, gusts under 15mph, 37/46F.

2/3: 2-4 inches (mixing with rain), gusts under 15mph, 34/38F.

2/4: Turning drier, wind gusts under 15mph, 32/40F.

Forecast Atmospheric River (AR)

Forecast Integrated Vapor Transport (IVT) valid for the South/Central CA coast. Notice the moderate AR surge with storm #2 on 2/4-2/5.

Forecast precipitable water content valid 2/3-2/4. The atmospheric river surge/plume is obvious.

This could result in eight inches of rain in Los Angeles 2/4-2/5.

Forecast Jet Stream

Storm #1 moves into UT/WY/CO/ID/MT/NM.

Storm #2 and trough sliding out of CA into UT/ID/WY/CO/NM.

Forecast Radar & Satellite

Forecast Totals

Grand Total snow by 2/10.

Bulk of snow timeline:

UT: 2/2

CO: 2/2-2/3

WY: Late 2/2 – AM 2/4

Bulk of snow timeline:

UT: 2/5-2/7.

CO: 2/6-2/9.

WY: 2/5-2/7.

Tomer’s Take: Grand totals are trending up in UT, CA, and CO with two different storm systems 2/1-2/9. I’m forecasting three grand total bullseyes in the Sierra, Wasatch, and Southwest CO. Both storm systems deliver a moderate intensity surge of Atmospheric River (AR) moisture to CA. Storm #1 hits now through 2/4, and storm #2 hits 2/5-2/9. On 2/3, a Panhandle Hooker storm system develops around the TX/OK Panhandle and forces snow (or rain/snow) development in Denver, Foothills, and Mountains. The intensity and track of this storm system dictates how much accumulation occurs at Loveland, A-Basin, Summit County, Winter Park, Keystone, and Eldora.

My afternoon forecast video update:

Old Man Winter Rally 2/4

Event takes place in Lyons, CO on 2/4.

2/2: Increasing clouds, gusts under 15mph, 35/44F.

2/3: 3-6 inches (mixing with rain), gusts under 15mph, 33/39F.

2/4: 1 inch snow until 9am then drier, wind gusts under 15mph, 32/37F.

Current Setup

Water vapor satellite shows both storm systems lined-up and escorted by a strong Subtropical jet.

Orange/red = drier air aloft.

Central/Northern CA radar shows heavy precipitation inbound. Snow hits Tahoe and Mammoth tonight into 2/1 above 7,000ft.

Forecast Atmospheric River

Forecast Integrated Vapor Transport (IVT) for the Central/Northern CA Coast at 38N/123W. Notice two moderate intensity AR surges.

Forecast Jet Stream

Storm #1 riding strong Subtropical jet 2/1-2/4.

Storm #2 with broad trough 2/5-2/9.

Forecast Radar & Satellite

Forecast Totals

Grand Totals: Storm #1 + Storm #2.

Totals are trending up in the Wasatch, CA, and CO.

Three bullseyes: Sierra, Wasatch, Southwest Colorado.

Storm #1.

Storm #2.

Tomer’s Take: Two different storm systems remain on track 2/1-2/8. Storm #1 (2/1-2/4) delivers a moderate intensity atmospheric river (AR) surge, widespread heavy interior Rockies snow accumulation, and a Panhandle Hooker storm system for Colorado on 2/3. Storm #2 (2/5-2/8) delivers a weak AR surge and moderate to heavy interior Rockies snow accumulation.

My afternoon forecast video update:

Old Man Winter Rally 2/4

Event takes place in Lyons, CO on 2/4.

2/2: Increasing clouds, Rain to snow after 10pm, gusts under 15mph, 34/40F.

2/3: 3-6 inches, gusts under 15mph, 32/34F.

2/4: Drier, cloudy, 29/38F.

Current Setup

Water vapor satellite shows both storm systems lined-up in the Pacific riding a powerful Subtropical jet stream.

Orange/red = drier air aloft.

Forecast Freezing Level

Forecast rain/snow line (daily min/max):

Sierra, CA:

1/31: Falling from 10,000′ to 7,400′.

2/1: Falling from 7000′ to 3600′.

2/2: 2300/5600′.

2/3: 5100/6200′.

2/4: 5600/7200′.

Wasatch, UT:

2/1: 7900/9400′.

2/2: 5600/7100′.

2/3: 3900/5200′.

2/4: 5900/6700′.

Forecast Atmospheric River

Forecast Integrated Vapor Transport (IVT) showing two AR surges.

Forecast Jet Stream

Storm #1 arrives with powerful Subtropical jet stream.

Storm #2. Notice the trough moving west to east through UT/AZ/NM/CO.

Forecast Radar & Satellite

Forecast Totals

Grand Totals: Storm #1 + Storm #2.

Storm #1.

Storm #2.

Tomer’s Take: Two different storm systems are lined-up 2/1-2/8 both riding a powerful Subtropical jet. Storm #1 (2/1-2/4) delivers a moderate intensity atmospheric river surge, widespread snow across the interior Rockies, and possible panhandle hooker storm system for Colorado (on 2/3). Storm #2 (2/5-2/8) could be strong for CA, then moves into the interior Rockies with another round of snow accumulation.

In the interim, abnormally warm temps continue with high freezing levels: 6-9K PNW/BC, 8-11K UT/CO.

My afternoon forecast update video:

Old Man Winter Rally 2/4

Event takes place in Lyons, CO on 2/4.

2/2: PM Rain to snow (1 inch late), gusts under 15mph, 38/41F.

2/3: 3-6 inches, gusts under 15mph, 32/35F.

2/4: AM flurries then drier, 29/36F.

Current Setup

Water vapor satellite shows the rich feed of moisture directed into the PNW/BC and large trough waiting in the North Pacific. This trough breaks loose and rides a powerful Subtropical jet into the West 2/1-2/8.

Orange/red = drier air aloft.

Forecast Atmospheric River

Forecast Integrated Vapor Transport (IVT) valid next 10 days for C/N CA Coast, 38N/123W. Notice the moderate intensity AR surge PM 1/31-2/1 with storm #1 and 2nd possible weak surge 2/5-2/6 with storm #2.

Forecast Jet Stream

Storm #1 arrives in CA with a powerful Subtropical jet then moves into the interior Rockies.

Deep trough off CA coast with Storm #2. Rapid intensification.

Forecast Radar & Satellite

Forecast Totals

Grand Totals 2/1-2/7: Storm #1 + Storm 2.

Storm #1. Watching for a Panhandle Hooker storm system in Colorado on 2/3.

Storm #2.

Northeast:

Light snow 2/1-2/2.

Tomer’s Take: Most places will feel the heat this week with abnormally warm Pacific air flooding the West. Snow levels jump significantly. Freezing levels run 6-9K in the PNW/BC and 8-11K in UT/CO. The first week of February still looks active with two different storm systems and progressively colder air. Widespread heavy snow accumulation possible.

My afternoon forecast video update:

Current Setup

Water vapor satellite shows a rich flow (Green Arrows) directed into the PNW/BC with high freezing levels through 1/31.

The big trough in the Pacific follows a strong Subtropical jet stream into the West on/after 2/1.

Orange/red = drier air aloft.

Forecast Jet Stream

Storm #1 rides a powerful Subtropical jet into CA then Intermountain West 2/1-2/5.

Storm #2 arrives 2/5-2/7.

Forecast Radar & Satellite

Forecast Totals

Northeast:

VT/NH/ME: Light to moderate snow accumulation PM 1/28-1/29, light accumulation 2/1-2/2.

Tomer’s Take: Snow continues in Colorado and New Mexico 1/26 tapering-off this afternoon/tonight. Then a ridge of high pressure builds across UT/WY/CO/NM 1/27-1/31 with abnormally warm air temps and a higher freezing level. During this timeframe, a rich moisture flow hits the PNW/BC pushing freezing levels high. The first week of February looks active with a strong Subtropical jet stream and trough of low pressure.

My afternoon forecast video update:

Forecast Freezing Level

Revelstoke & Kicking Horse, BC (Min/Max):

1/26: 2800/3800′

1/27: 3400/5600′

1/28: 5100/6100′

1/29: 6400/7100′

1/30: 7200/8500′

Alta/Snowbird, UT (Max/Min):

1/26: 4300/5200′

1/27: 7500/8400′

1/28: 8900/9400′

1/29: 10300/11200′

1/30: 11500/11600′

Current Setup

Water vapor satellite shows a shifting pattern. The bulk of moisture will now be directed into the PNW/BC through 1/31.

Orange/red = drier air aloft.

Forecast Jet Stream

Ridge of high pressure UT/WY/CO/NM 1/27-1/31.

Pattern shifts and door swings wide open with rich moisture transport into the West.

Strong Subtropical jet stream transports areas of low pressure into the West.

Forecast Radar & Satellite

Forecast Totals

VT/NH/ME:

Rain/Snow 1/26, Snow 1/28-1/29, 2/1-2/2.