Marine Weather and Tide Forecast for South Lake Tahoe, CA

DISCUSSION

Weak low pressure resides off the northern CA coast per 19Z moisture channel imagery and will govern our weather through Thursday as it lifts across the region. The main impact will be increased afternoon breezes today and Wednesday, elevating fire concerns along the Sierra Front into the W NV Basin and Range each afternoon. Winds weaken after Wednesday in the wake of a dry cold front passage Wednesday night.

Weak instability will overspread the Surprise Valley and far N Washoe County Wednesday afternoon as the low tracks across southern OR, supporting a low, 10-20% chance isolated showers and thunderstorms. Otherwise, the weak low will keep it seasonably hot through midweek with regional highs in the upper 70s-80s and upper 80s-90s for Sierra and western Nevada communities, respectively.

Broad high pressure amplifies across the western states at the end of the week as the low departs the region. Temperatures steadily warm Thursday into the weekend in response, culminating in a heatwave over the weekend that may extend into early next week.
While this heat won't be record-breaking, it will increase the potential for heat illnesses/impacts as moderate (2 out of 4)
HeatRisk settles in Sierra and western Nevada valleys. Triple digit heat will be common across western Nevada this weekend -- likely giving Reno its first 100F day of 2025 on Saturday -- with locally major HeatRisk possible in lowest valleys Sunday and Monday. Be sure to make your weekend plans accordingly and practice your heat safety precautions if you venture outdoors!

-Salas

AVIATION

The main weather concern will be breezy west winds (gusts of 20-30 kts) this afternoon and Wednesday afternoon, possibly resulting in low-end LLWS impacts each afternoon -- especially at KRNO-KCXP-MEV.
A warming trend may pose density altitude issues this weekend areawide but most particularly at KNFL-KLOL-KHTH where triple digit heat is expected each afternoon from Friday into early next week.

-Salas

FIRE WEATHER

Gusty west winds and RH reductions to 7-12% will result in 1-3 hours of critical conditions across the Sierra Front and western Nevada Wednesday afternoon. Some localized wind prone sites may see up to 6 hours of critical conditions. Winds shift to N/NW Wednesday night as a dry cold front advances across the region. Winds weaken after Wednesday and become predominantly N/NE.

Strong high pressure will produce above normal temperatures and expand areas of poor overnight recoveries into higher elevations this weekend into early next week. Nighttime RHs will struggle to 30% in western Nevada this weekend.

-Salas

REV Watches/Warnings/Advisories
NV...None.
CA...None.