The Morning Intel | Tahoe Sector Watch

Location: #HippieHaus | South Lake Tahoe, CA

Date: Friday, December 12, 2025

¡Buenos días, my friends

Cup'O'Joe in hand, #StokeLevelRising up slightly to a 13.1 as we increase confidence in a pattern change next week with light precipitation. However, we are still uncertain about the timing and impacts. Current forecast model guidance now shows Monday afternoon as the onset of precipitation, with chances of high elevation snow (9k👆).

Forecast guidance and models now show Monday afternoon as the onset of precipitation chances over the mountains, which will shift to an unsettled pattern, with the best chances of impactful weather over the mountains and northern Sac Valley.

With the strength of the current ridge, we may see the forecast trend shift later as it attempts to break down, allowing precipitation to impact the area. The Current Climate Prediction Center forecast points to a >60 percent chance of above-normal precipitation over northern CA, peaking in the north half of our CWA from Dec. 19-25.

Changes from Yesterday's Forecast

  • Timing Shift (Onset): Yesterday, we looked generally at "early next week." Today's Update: The models have dialed in the onset to Monday afternoon (Dec 15).

  • Storm Type: Yesterday, we discussed a generic "shortwave." Today's Update: The NWS explicitly mentions the region being "clipped by the southern tip of an Atmospheric River" moving into the Pacific Northwest.

  • Snow Levels (Elevation Rise): Yesterday, we tracked levels at 8,000-9,000 ft. Today's Update: Snow levels have crept higher to 👆 9,000-9,500 ft. This means snow accumulation is likely restricted to the very highest peaks (30% chance).

  • Precipitation Amounts: Confidence has increased in liquid amounts. Blended guidance now suggests a 40% chance of exceeding 0.7" of liquid along the Sierra crest (up from 0.25" yesterday), though mostly as rain/snain below 9k.

  • Long Range Outlook: Confidence is increasing for the Dec 19-25 window, with CPC outlooks now showing a >60% chance of above-normal precipitation, potentially setting up a white Christmas scenario.

Today's Intel

  • 🚠 Bullwheels Turning: KirkwoodMtn, Heavenly, Mt Rose, MammothMtn, Palisades, Boreal, Northstar.

  • 🌡️ Temps: Unseasonably Warm. Highs 15-20º degrees above average. South Lake Tahoe and Reno challenging records again today.

  • 🌫️ Conditions: Freezing Fog socked in this morning over the lake and Sierra valleys. It should burn off, but low stratus may linger.

  • 🚗 Roads: ALL CLEAR in the Sierra. Dense Fog Advisory in the Sacramento/Solano Valleys (Hwy 50 / I-80).

The RS Mindset: The ridge is stubborn, but the signals are there. We are tracking a pattern shift next week that tries to open the storm door. For now, we celebrate the Mtn Teams keeping the cord-carvaliciously fresh despite the inversions. Patience is the practice.

Looking forward to the next 3–7 days:

  • Potential Rain and Snow Outlook: Dry Pattern Continues through the Weekend. High pressure remains anchored.

  • Forecast Deep Dive:

  • Monday PM: The ridge dents. Precip onset begins in the afternoon.

  • Tuesday: The Sierra gets clipped by the AR tail. Expect breezy conditions and high-elevation rain/snain.

  • Mid-Week: Unsettled zonal flow keeps us on the southern periphery of storms.

  • Temperatures: Near Record Warmth. Highs will be 10-15º degrees above average through the weekend.

  • Winds / Wind Conditions: Light. Winds remain light and terrain-driven through the weekend.

  • Road Conditions: ALL CLEAR. Watch for brake checks on I-80 West.

The Weather Ahead | Temperatures | Winds | Winter

Forecasted Temperatures (Today's High / Tonight's Low):

  • #HippieHaus (SLT / 6,380'): 57° / 33°

  • Kirkwood (Base / 7,800'): 52° / 30°

  • Truckee (North Shore / 5,800'): 57° / 28°

  • Mammoth Mtn (Base / 8,900'): 42° / 38°

Timing of wind direction/wind speeds: Light/Variable winds today (ESE 3mph at HippieHaus). No significant wind events expected.

Seven(7) Day forecast (Lake Level Highs/Lows):

  • Today (Fri): 57° / 33° (Sunny, Freezing Fog AM)

  • Saturday: 57° / 32° (Sunny)

  • Sunday: 55° / 30° (Sunny)

  • Monday: 53° / 32° (Increasing Clouds, PM Showers?)

  • Tuesday: 50° / 34° (Chance of Rain - Snow Level 9k)

  • Wednesday: 48° / 32° (Chance of Rain/Snow High Elevation)

  • Thursday: 46° / 30° (Unsettled)

Sierra Avalanche Center (Tahoe / Carson Pass):

  • Status: #LowTide.

  • Hazard: Shallow Obstacles.

  • Discussion: Shallow snowpack. Avalanche concerns exist in isolated areas where hard, supportable slabs of wind-drifted snow exist on top of weak sugary snow.

  • Link: https://bit.ly/SierraAvyForecast

Eastern Sierra Avalanche Center (Mammoth Zone):

⚓ Marine Forecast for Lake Tahoe:

  • Status: NO HAZARDOUS WEATHER.

  • TODAY: Mostly cloudy AM, clearing. Freezing Fog in the morning. Light winds. Highs 52-57. Wave Heights < 1 foot.

  • TONIGHT: Clear. Light winds. Lows 33-41. Wave Heights < 1 foot.

  • SATURDAY: Sunny. Light winds. Highs around 57.

  • Water Temp: 49.0°F.

  • Mariner Note: Glassy conditions. Highly recommend a 4/3 or 5/4 wetty if you are paddling/foiling due to cold water shock risk.

✈️ Aviation Forecast (Detailed for Pilots):

  • Conditions: VFR prevails, BUT...

  • Hazards:

  • FZFG (Freezing Fog): Prevalent this morning at KTRK (Truckee) and KTVL (Tahoe). Should burn off just after sunrise.

  • Stratus: Low stratus deck socked in over Tahoe/Sierra valleys may linger.

  • Haze: Valley inversions producing haze for Western NV terminals.

  • Winds: Light surface winds.

Area Forecast Discussions (AFDs) Summaries

For #HippieHaus & Mammoth (NWS Reno):

  • Fog Update: "Freezing fog and in some areas a low stratus deck are socked in over Lake Tahoe... Light winds this afternoon may not be enough to fully mix out the low clouds."

  • Pattern Shift: "Next Tuesday and Wednesday we'll likely see a little precipitation... clipped by the southern tip of an atmospheric river."

  • Snow Levels: "Hover around 9,000-9,500' 👆during this round... just the highest peaks have the greatest chance (30%) to see any snow."

  • Long Range: "Encouraging sign for those who want POW for Christmas... Trough setting up off the west coast towards the end of the month."

For Carson Pass / KirkwoodMtn Zone (NWS Sacramento):

  • Valley Focus: Dense Fog Advisory continues.

  • Mountain Focus: "Increasingly mild temperatures with sunny skies and dry weather."

  • Precip Update: "Current forecast now shows Monday afternoon as the onset of precipitation chances over the mountains."

On this #FreedomFriday, we hold fast on the #StokeLevel - NO~#OverStoking, NO~Whiners. The fog is lifting, the sun is shining, the winds are on our shoulders, with the long-range models teasing us with a Christmas miracle. Enjoy the weekend, keep your edges sharp, head on a swivel, and stay tuned for the pattern flip. Patience is the practice.

Stay'nThirsty for POW

Coop | RS#69

ECMWF AIFS ENS [M] 0.25º 6-hr Precip (in.), MSLP (hPa), 850mb Temp.(ºC)

A weather map showing North America with isobars, precipitation, and pressure systems. Major high-pressure areas are marked with 'H' and low-pressure areas with 'L'. Green and yellow colors indicate areas of rain, with heavier rain likely in the North Atlantic and eastern Canada, and some precipitation on the west coast. The map includes data on temperature, precipitation, and atmospheric pressure.

ECMWF AIFS ENS [M] 0.25º 500mb Height (dam) and Anomaly - 5 day

A weather map of North America showing 500 mb height and anomalies, with a large cold area over northern Canada in blue and purple shades, and a high-pressure warm area over the southwestern US in red and orange shades, indicating different weather patterns.

ECMWF AIFS ENS [M] 0.25º QPF 10-day Anomaly (Inches)

Map of the United States showing 5-day weather anomaly forecast for December 16, 2025, with areas of precipitation and temperature deviations. Green indicates above-normal precipitation, brown indicates below-normal, and blue and red indicate deviations in temperature or precipitation levels.

ECMWF AIFS ENS [M] 0.25º Precipitable Water Anomaly (Precent of Normal)

A weather map of North America showing 10-day rainfall anomalies, with areas of above-average rainfall shaded in green and below-average rainfall in brown, and notable dry and wet regions across the United States, Canada, and surrounding areas.

ECMWF AIFS ENS [M] 0.25º Precipitable Water (Inches)

Map of North America showing predicted precipitation levels in inches for December 12, 2025, with higher rainfall in the southeastern U.S. and parts of the Pacific Ocean, and minimal precipitation in northern Canada and the Arctic.

ECMWF AIFS ENS [M] 0.25º Total Precipitation (Inches)

A weather map showing total precipitation in inches across parts of the Western United States, including California, Nevada, and surrounding states, with no significant rainfall indicated.

Chair Six(6) Ridge 12/11 - KirkwoodMtn - 9,100’

Graph showing wind direction in green, wind speed in blue, and gusts in red over 24 hours, with a switch labeled 'Heat Off/On'. Below is a table with timestamped weather data including air temperature, wet bulb, relative humidity, wind direction, speed, gust, and voltage readings.

NAM 12Km 6hr Precip, MSLP, 850mb Temp (Cº)

A weather map showing 6-hour precipitation, mean sea level pressure, and 850 mb temperature across parts of California, Nevada, and surrounding states. It features black lines for isobars, red lines for temperature contours, and a blue 'H' denoting a high-pressure system.

NAM 12km | Composite Precip Type & Cloud Cover

Map of California and surrounding areas showing composite reflectivity, precipitation type, and total cloud cover. The map includes weather station codes and coastlines, with varying shades indicating different levels of precipitation or cloud cover.
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NAM 3km | 24hr Precipitation (in)

Map showing 24-hour snowfall in inches across the Northwest United States, with the highest snowfall of 20.6 inches in parts of Northern Washington state, valid for December 13, 2025.

NBM 2.5km West-Conus | 24hr Snow (in)

NAM 3km Composite Reflectivity 1000m AGL

Map showing atmospheric reflectivity (dBZ) over California and surrounding areas at 1000 meters altitude, valid for 06z on December 12, 2025.

WPC 2.5km 24hr Snow 90 Percentile (Inches)

Snowfall forecast map for the Pacific Northwest and surrounding regions, showing 24-hour snowfall accumulation in inches, valid for December 13, 2025 at 12:00 UTC, with higher snowfall amounts indicated in pink and purple, especially over northern Washington and western Canada.
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NAM 3km | 2m Temperatures - MAX (ºf)

Map of California showing 24-hour minimum temperatures in Fahrenheit, with colder areas in blue and warmer areas in yellow and orange, indicating temperatures ranging from 15.9°F to 71.1°F.

NAM 3km | 80m Wind Speeds + Streamlines (kts)

Weather map showing wind streamlines and speed in knots for California and surrounding areas, with a low-pressure system offshore bringing strong winds and storm activity.

NAM 3km | 0-6km Wind Shear (kts) + Streamlines

Weather map showing wind shear in knots across the Pacific Northwest and parts of California, Oregon, and Idaho, with color-coded regions indicating varying wind speeds and directions for December 12, 2025.

NAM 3km | 2m Temperatures - MIN ºf)

NAM 3km | 925mb Wind (kts) + Streamlines

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Map showing snow accumulation in inches across parts of Idaho, Oregon, Nevada, Utah, and surrounding states, valid for 6z on December 13, 2025.

NAM 3km | 24hr Snow (10:1 Ratio) Utah

NAM 3km | 24hr Snow (10:1 Ratio) Colorado

Weather map showing snow accumulation in inches over a region of the United States, with a focus on northern states, valid at 6 am on December 12, 2025.

NAM 3km | 24hr Snow (10:1 Ratio) Washington

Weather map showing snow in northern Montana and southeastern Canada with varying intensities indicated by different shades of pink and blue, and several small scattered snow areas across the western United States.

NAM 3km | 24hr Snow (10:1 Ratio) British Columbia

Weather map showing snowfall and snow water ratio across Alaska and parts of Canada, with color coding indicating snow levels in centimeters. Darker blue and pink areas represent higher snowfall, with values up to 25.5 cm, and gray areas indicate little to no snowfall.

NAM 3km | 24hr Snow (10:1 Ratio) Alaska

Map showing 24-hour snow accumulation in centimeters across Alaska, with color coding from light to dark blue and purple indicating higher snowfall, and grey areas indicating no snow.
Map showing snow forecast in inches across parts of the Western United States and Canada, valid for December 12, 2025, at 6 am.

NAM 3km | 24hr Snow (10:1 Ratio) Idaho

NAM 3km | 24hr Snow (10:1 Ratio) Montana

Weather map showing snow accumulation in inches across parts of the Northwestern United States. The map indicates areas with heavy snowfall, especially in the mountainous regions, with some locations experiencing over 20 inches of snow. The map includes a color scale at the bottom for snow depth, and geographic labels for latitude and longitude.

NAM 3km | 24hr Snow (10:1 Ratio) Wyoming

Weather map showing NAM 3 km forecast of snowfall in inches for December 11, 2025, at 06:00 UTC. The map covers parts of the western United States, including areas of heavy snowfall indicated by pink and purple, especially in northern Nevada, Idaho, and parts of Montana. Light snow is spread across other regions.

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