Truckee, CA 96161 Weather

Key Messages

* Areas of light rain from northeast CA to west central NV will diminish this morning, with isolated showers lingering near the Sierra today.

* Gusty northeast to east winds tonight into Saturday bring choppy conditions on Lake Tahoe and low wind chills on exposed Sierra peaks.

* Dry weather and cold nights prevail this weekend. A weaker storm may bring increased breezes and low chances for showers near the Oregon border early next week.

Discussion

Latest radar loop shows an area of mainly light rain (recent rates generally less than 0.10"/hour) near and north of I-80 across northeast CA-western NV. As the upper low centered over north central NV weakens and drifts into eastern NV later today, this rain area will diminish through the morning as it moves into Pershing/Churchill counties. A cold front dropping southward across western NV and the eastern Sierra may support isolated light rain and high elevation snow showers into Mineral-Mono counties through this afternoon, but little or no additional precip amounts are expected.

Otherwise for today, brisk northwest to north winds will reinforce the colder post-frontal air mass with highs only in the 50s for most areas today. A short period of choppy lake conditions may occur on Pyramid Lake this morning with gusts near 30 mph, before decreasing to near 20 mph during the afternoon.

For tonight, winds shift to the northeast and east with stronger ridge gusts of 50-60 mph over the Sierra crest. A lake wind advisory remains in effect for Tahoe tonight into Saturday morning as some of these gusty winds mix down and produce choppy conditions for western shores. While most areas will see clearing skies, moist upslope flow will lead to a lower cloud deck forming along the eastern Sierra and into adjacent parts of western NV tonight into Saturday morning.

For the remainder of the weekend, dry conditions and light winds prevail, with a slow warmup to near late October averages in the 60s for most areas by Sunday. Nights will remain on the cool side with lows mainly in the 20s to lower 30s, and teens for Sierra valleys and typically colder low elevation sites.

For early next week, a weaker low pressure tracking across the Pacific NW may brush across far northeast CA and northwest NV with 15-30% chances for light rain showers Monday afternoon-night. Otherwise, this system is more likely to bring a period of increased afternoon breezes (current forecast gusts 25-30 mph, locally up to 35 mph) mainly from I-80 northward, followed by slight cooling Tuesday. The bulk of next week still favors dry conditions prevailing, although longer range guidance shows signals for a more active storm pattern returning as soon as the end of October, but more likely delayed until early November. MJD

Aviation

Areas of -RA with periods of MVFR CIGS and terrain obscurations at the main terminals (excluding KMMH) this morning with improving conditions after 14-16Z. Patchy fog/low stratus may produce brief IFR periods at KTRK thru 16Z. For KMMH, clouds increase later this morning with terrain obscurations and patchy MVFR CIGS. Otherwise, VFR conditions prevail this afternoon with NW-N breezes 15-20 kt at times.

For tonight, increasing NE-E FL100 winds with gusts 40-50 kt produce areas of mountain wave turbulence near and west of the Sierra crest and Carson Range. Lighter NE flow with residual moisture produces a SCT-BKN deck of stratocumulus for the E Sierra/western NV terminals (KMMH-KMEV-KCXP-KRNO) this evening thru Saturday morning (mainly 04-18Z), mainly producing terrain obscurations but can't rule out periods of MVFR CIGS especially at KMMH. Lower chances (20-30%) of patchy FZFG at KTRK between 10-16Z Saturday AM with leftover moisture from recent rain, but also a limiting factor of drier NE-E winds.

For the remainder of the weekend, VFR and light winds prevail, except for patchy FZFG at KTRK (30-50% chance) between 10-16Z Sunday morning. MJD