Tomer’s Take: This is an afternoon update with new numbers for the Northeast. It assumes a stronger storm system.
Potential East Coast/Northeast storm system 11/25-11/26 with a big dip in the jet stream. Intensity and track are still in question.
Moisture starts sneaking through the ridge into the PNW/BC on 11/22.
Deeper moisture breaks the ridge 11/25-11/29 affecting more of the West. A trough could sit across the West through 11/29.
Current Setup
Infrared/visible satellite shows the storm track, Western high pressure ridge, and amplifying low pressure systems that will eventually displace the high.
Afternoon Update: New Numbers for East
This assumes a stronger East Coast storm system.
Forecast jet stream valid 11/25/2022. This is a powerful, amplified jet flow capable of generating a large storm system.
This assumes a stronger storm system.
Forecast snow totals (inches) valid 11/21-11/27.
Let’s see what the afternoon numbers look like out West after the pattern shift.
A see-saw jet stream setting up East versus West through Thanksgiving (ridge West, trough East).
Robust high pressure ridge over AK/BC/PNW is problematic through Thanksgiving keeping most of the West drier than normal.
Out East, a strong storm system possible for Thanksgiving Weekend.
When will the pattern flip? Possibly on/after 11/27. See below.
Current Setup
Infrared satellite shows the robust ridge over the PNW/BC/AK and ridge amplifiers to its West over the NPAC.
This also creates the see-saw jet pattern with large trough over the East.
Thanksgiving Pattern
High pressure remains strong through 11/24 with jet axis bending far north into Canada. This leaves most of the Rockies drier than normal.
Forecast jet flow valid 11/27. Now this is a different story with a breakdown of the ridge and lower atmospheric pressures plus a strong jet buckling south. This pattern would feed moisture into the PNW and interior Rockies.
East Coast Storm System?
Forecast jet stream valid 11/26 shows a large dip in the jet stream over the East/Northeast and powerful jet streak. Best snow with this setup occurs interior-north through NH, VT, ME. But, this is not set in stone and my feeling is the track and intensity are still a question mark.
Current fast N-S jet flow through MT, WY, CO gradually ends.
Much drier pattern for West continues.
Pattern shift for PNW/BC, MT, ID, WY on/after 11/21 but it’s not optimal.
Jet axis bends even further north keeping most of the Rockies drier than normal.
Eastern/Northeast: A larger Thanksgiving weekend storm system possible 11/25-11/27.
Current Setup
Infrared satellite shows the storm track, fast N-S jet flow with cold front, and robust PNW high pressure ridge.
Thanksgiving Pattern
Forecast jet stream flow on Thanksgiving 11/24 shows the shifting pattern with the jet axis bending far to the north. Some moisture feeds into the PNW/BC/Banff. The trend is for this bend to bend even further north keeping CA, UT, CO, NM drier.
Forecast jet stream flow on 11/26. The axis stays put with CA, UT, CO, NM staying dry.
Northeast Storm System?
Forecast jet stream flow valid 11/25 suggests a large dip supporting a developing area of low pressure. This is something to watch.
Forecast Timing
Forecast radar/satellite valid 11/18-11/23.
Forecast Snowfall
Forecast total snowfall (inches) valid 11/18-11/20.
Talk about an incredibly dry period with robust ridging over the PNW/BC.
Forecast total snowfall (inches) valid 11/21-11/26.
Even after a pattern shift on/after 11/21 the jet axis bends far to the north leaving most of the Rockies dry.
Fast N-S jet flow 11/17-11/18 delivers light snow accumulation to WY and CO and much colder air temps.
In Colorado, moderate snow accumulation likely in the Foothills of Boulder and Larimer Counties with 5-10 inches of total accumulation.
PNW/BC stay dry through 11/20 then pattern shifts on/after 11/21.
Best snow on/after 11/21 favors PNW/BC/Banff and northern tier of the Rockies.
Pattern does not immediately favor UT, CO, NM, CA but might in the longer term.
Watching Thanksgiving weekend for possible East/Northeast coastal low.
Current Setup
Infrared satellite shows the storm track, robust Eastern Pacific high pressure ridge, and strong cold front racing through MT, WY, CO on a fast N-S jet.
Thanksgiving Pattern Shift
Forecast jet flow valid 11/18 shows the robust PNW high pressure ridge and fast N-S jet flow through MT, WY, CO.
Forecast jet flow valid 11/25 shows a complete pattern shift. A powerful jet stream has replaced the PNW high pressure ridge. The axis is so far north that the best snow favors PNW/BC and northern tier of the rockies.
In Colorado, moderate snow accumulation likely in the Foothills of Boulder and Larimer Counties with 5-10 inches of total accumulation. Eldora, Longs Peak, Cameron Pass, and the Indian Peaks all included.
Overnight lows into Friday morning reach -10 to -20F on the CO 13ers/14ers.
Today, a coastal low is spreading moderate snow to northern VT, northern NH, and northern ME.
Significant lake effect snow near the Great Lakes will follow.
A robust ridge of high pressure leaves the PNW/BC/CA high and dry through 11/20.
Then a pattern shift is likely on/after 11/21.
Jet pattern on/after 11/21 is strong but axis might favor northern tier of the Rockies.
Current Setup
Infrared satellite shows the storm track, high pressure ridge, and amplifying area of low pressure. Also notice the N-S fast moving cold front racing south from Banff into MT, WY, CO, northern NM.
Northeast Snow
Forecast snow totals (inches) 11/16-11/22. Most of this falls today (11/16) with the coastal low.
Pattern Shift PNW
The current jet stream flow is dominated by high pressure over the PNW/BC and a fast N-S jet from Banff to MT to WY to CO.
Lower atmospheric pressures and a powerful jet stream move into the PNW/BC on/after 11/21. While this is great for the PNW/BC, it doesn’t favor the southern tier of the Rockies given the northern axis of the jet.
PNW/Western BC/CA stay mostly dry through 11/20 with high pressure ridge.
Then the pattern shifts on/after 11/21 as the high gets dislodged and lower pressures move into the PNW/BC with a powerful jet.
Between 11/14-11/21 the Intermountain West stays active with fast-moving north to south cold fronts but only light snow accumulations. This favors Banff, MT, WY, CO, NM.
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My forecast video 11/14:
Current Setup
Infrared satellite shows the storm track, high pressure building into the PNW, and powerful low tracking into AK. This low will reinforce the high pressure ridge across the PNW/BC/CA through 11/20 before the pattern changes.
Pattern Change On/After 11-21
Forecast jet stream flow valid 11/16. Notice the high pressure ridge draped across CA/PNW/BC and fast N-S flow from Banff to MT to WY to CO.
Forecast jet stream valid 11/22. Notice the high pressure ridge is gone from the PNW/BC and is replaced with a powerful jet stream/streak. This would translate into precipitation for the PNW/Banff/BC.
There are no big storm cycles on the immediate horizon for the West.
This week favors the Intermountain West including MT, WY, CO, NM. Total snowfall next 8 days is 10″ or less for all resorts in this grouping.
Beyond 11/20, the PNW turns more active as high pressure slides east and a trough of low pressure replaces with a powerful jet stream. Details and graphic below.
Southern Track Low
Visible satellite shows the storm track, big high building into the PNW, a cold front racing south from Canada, and a southern track low headed for NM and southern CO.
November 13-22
Forecast jet stream flow valid 11/14.
Forecast jet stream flow valid 11/20. Notice the high pressure ridge sliding east opening the door for the low and powerful jet lurking over the Pacific.
Forecast jet stream flow valid 11/22. Big pattern change here. Powerful jet knifing in with low pressure replacing the high pressure ridge. This would equate to wind, colder temps, and snowfall.
Currently a weak low is sliding south from the PNW to CA. It’s headed to NM and southern CO as a southern track low through 11/14.
This low opens the door for a large trough to develop across the Intermountain West (MT, WY, CO) with a stiff northerly flow from Canada through 11/19.
The PNW/BC/West Coast gets a large ridge of high pressure through 11/19.
What’s beyond 11/19? Data is mixed but the PNW could turn slightly more active.
Bottom line: No big storm cycles on the horizon.
Current Setup
Infrared satellite shows the storm track, weak low pressure in the PNW sliding south, a second low headed for AK/Canada, and a high pressure that will become the dominate feature for the PNW/West Coast through 11/19.
November 12-19
Forecast jet stream flow 11/14. Notice the weak low sliding south through CA with light snow accumulation. Behind it a large ridge of high pressure amplifies the jet stream. This in turn sends it south through MT, WY, CO with colder air and fast-moving cold fronts and light snow chances.
Forecast jet stream flow valid 11/17. Big dip in the jet continues for MT, WY, CO.
Below is one possible pattern valid 11/24/2022. It shows a slight preference for lower mid-atmosphere pressures in the PNW/BC. Higher pressures are possible for parts of the Intermountain West.
This would mean most of the snow/colder temps are in the PNW/BC.
Pattern is now in transition. A low slides down the West Coast but it weakens and dries up with only light mountain snow accumulation.
This low becomes a weak southern track low that slides through the southern tier of the Rockies through 11/14. Behind it the pattern changes quickly to a high pressure ridge in the PNW/BC and large trough across the Intermountain West.
This is a colder, drier pattern overall with only light snow accumulation.
Bottom line: No big storm cycles on the short-term horizon.
What about the end of November? Pattern appears to turn slightly more active for the West. This could last into early December. But, the overall signal is weak.
Current Setup
Infrared satellite shows the first low moving through the PNW and headed south into CA. It will weaken as it moves with only light snow accumulation. It then becomes a weak southern track low.
The 2nd low pressure slides into AK/Canada.
Mid November Pattern
Forecast jet stream flow valid 11/14 illustrates the PNW/West Coast high pressure ridge. You can also see the southern track low with some southern branch support, but overall it’s weak.
Forecast jet stream valid 11/17 shows a progressive west to east flow with larger high pressure ridging. Lack of amplification means no big storm systems.
What about late November?
Some data suggest a slightly more active pattern for the West and West Coast. This could last into early December. But, the overall signal is weak.