The Morning Intel | Tahoe Sector Watch

Location: #HippieHaus | South Lake Tahoe, CA

Date: Sunday, December 14, 2025

¡Buenos días my friends,

Cup'O'Joe in hand, #StokeLevelSolid, as I read through the NWS reports on a #SoulShineSunday morning. Slow to post, slept in till 0600 for shits-and-giggles, nice to grab a few extra minutes of time behind the eyelids.

Ok, let's go - Forecasting guidance models are all way too kind to us this morning, feels like a set-up or a prank. I am hesitant to go full 13+ on the #StokeLevel, and I am feeling a little Loki effect, that lil-cunning trickster might be spiking my Cup'O as it is looking like the possibility, chance of, could be a #WhiteChristmas are starting to align.

Guidance, as is written this morning, has the #StormDoorOpening, AND in an extended period, as in days, not hours, and over a week? Prognosticators, dropping in numerical values for snow accumulations? 26" to 38"-ish - 12/20-12/28? What? Pinch me, and let's take a run through the numbers...

Current Conditions & Sector Data

Regional Temperatures:

  • South Lake Tahoe (KTLV) at 6,308': 28ºF

  • Truckee (KTRK) at 5,899': 19ºF (Deep freeze TRK Style)

  • Mammoth Mtn Race (MTH03) at 11,034': 32ºF

  • Chair 6 Ridge (9,100'): 39ºF (Inversions locked in)

Regional Winds:

  • HippieHaus: 226º (SW) 2mph

  • Truckee: 212º (SSW) 1mph

  • Donner Pass: 208º (SSW) 6mph

  • Carson Pass: 196º (SSW) 3mph

Roads (CalTrans @ 0519):

  • Sierra Sector: ALL CLEAR (SR88, Hwy 50, I-80).

  • Valley Warning: Dense Fog Advisory for Solano/Yolo/Sacramento lines. Westbound I-80 trucks must stop at the Nyack brake check.

Lake Tahoe Marine Forecast:

  • Today: Cloudy AM with Fog, then clearing. Light winds. Highs 53-58.

  • Mariner Note: Water temp is 48.8ºF. Cold water shock is real; dress accordingly if you are paddling.

Forecast Update: Changes & The Nuance

We are tracking a dynamic situation. Comparing today's data against yesterday, here is what has shifted:

1. Snow Levels Trending Higher (The "Ouch" Factor):

  • Yesterday: We were hoping for snow levels around 9,000'.

  • Today's Change: NWS Reno has bumped snow levels for the Tuesday/Wednesday system up to 9,500' - 10,000'.

  • Impact: This means the initial wave is almost certainly RAIN or Snain at all resort bases and even mid-mountain. #MaNatural will be reserved for the highest peaks only.

2. Wind Intensity Confirmation:

  • Update: The "conceivable" gusts mentioned yesterday are now looking more likely. Expect 80-100 mph gusts on Sierra ridgetops Tuesday afternoon through Wednesday.

3. The Thunder Surprise (AFD Nuance):

  • Critical Detail: NWS Sacramento is spotting something Reno isn't emphasizing—Thunderstorm Chances (15-25%).

  • Timing: Tuesday afternoon through Wednesday.

  • Implication: This indicates high energy/instability. Lightning holds are a real possibility for lift operations mid-week.

4. The Colder End-Game:

  • New Data: While the start is warm, NWS Sacramento notes snow levels diminishing to 6,500-7,500 ft late Wednesday. This suggests the colder air we need is trailing the moisture.

NWS Reno (HippieHaus & Mammoth):

  • The Vibe: "Storm door remains open."

  • Precip: Probability has increased to 60-70% for Tuesday PM - Wednesday.

  • Mammoth Specific: Precip chances are lower for Southern Mono (10-40%) compared to the Tahoe Basin.

  • Long Range: Active pattern likely continues into the last week of December.

NWS Sacramento (Kirkwood / West Slope):

  • The Vibe: "Confidence continues to increase."

  • Key Differentiator: They are explicitly calling out Isolated Thunder chances.

  • Snow Levels: They acknowledge the high start (>8k) but offer hope for a drop to 6,500' late Wednesday.

Aviation:

  • Current Status: LIFR/IFR conditions are locked in this morning due to Freezing Fog (FZFG) and low ceilings at KTRK (Truckee) and KTVL (South Lake Tahoe).

  • Forecast: Fog should burn off around 18z (10:00 AM PST), clearing to VFR for the afternoon.

  • Hazards:

  • Icing: Pockets of icing on roads and potentially airframes in the fog layer.

  • Slantwise Visibility: KRNO, KCXP, and KMEV will struggle with haze due to inversions.

  • Turbulence: Smooth today, but Severe Turbulence is expected to ramp up Tuesday afternoon with the onset of 80-100kt ridge level winds.

Sierra Avalanche Centers

Central Sierra (Tahoe/Carson):

  • Status: Watch Mode.

  • Hazard: Shallow snowpack and obstacles.

  • Forecast: Daily avalanche forecasts will resume next week as the active pattern begins.

Eastside Region (Mammoth):

  • Status: Low Tide.

  • Hazard: Shallow coverage. Isolated wind slabs may exist.

My friends, the data is tantalizing. While the Tuesday wave brings us the "warm sponge" treatment with high snow levels, it is the key that unlocks the Storm Door. If the long-range prognosticators are right about that 26" to 38" window for Christmas week, we are in for a treat. However, and for today? Enjoy the #SundaySoulShine. It feels like spring, the birds are chirp'n, and the Mtn Teams are working magic on the snow surfaces we have. Get out there, rip some turns, and get ready to batten down the hatches for Tuesday.

Stay'nThirsty for POW,

Coop | RS#69

Map of North America showing weather patterns with high and low pressure systems, precipitation areas in green, and various temperature and pressure contour lines.
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ECMWF AIFS ENS [M] 0.25º 6-hr Precip (in.), MSLP (hPa), 850mb Temp.(ºC)

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Chair Six(6) Ridge 12/14 - KirkwoodMtn - 9,100’

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Cooper Marketing & Media - Lake Tahoe Weather - Daily Lake Tahoe Snow forecasts - Accurate Lake Tahoe Weather | Lake Tahoe Snow and Resort Forecast
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