textproduct: Reno

KEY MESSAGES

* Gusty winds will pose impacts to holiday travel and recreation, with elevated fire concerns across Mono and Mineral counties.

* Chances of rain and isolated thunderstorms increase across Lassen, the Surprise Valley, and N Washoe County this afternoon.

* Warmer and drier weather is favored next week with low shower and thunderstorm chances along the E Sierra around midweek.

DISCUSSION

An upper shortwave embedded within the broader western trough will pivot through the Pacific Northwest today, dislodging a surface cold front as it does so. In response, S-SW gusts increase to 30-40 mph in the afternoon, shifting to W-NW in the early evening when the front passes through. Ridgetop winds will gust to 60+ mph at times. Be prepared for rougher lake waters, turbulent flights, and blowing dust/reduced visibilities near desert sinks and playas. Dry and windy conditions will also elevate fire concerns from Mono County into S.Lyon/Mineral counties this afternoon (more details below).

Shower and thunderstorm development will be focused near the Oregon border closer to the center of the upper low where deeper moisture, weak instability, and forcing for ascent are co-located. Rain chances increase to 30-60% across N Lassen County, the Surprise Valley, and far N Washoe County this afternoon, with hi-res ensembles suggesting a 20-40% probability of isolated thunderstorms. Potential thunderstorm hazards include brief heavy rain, strong outflow gusts of 45+ mph, small hail/graupel, and occasional lightning.

Labor Day is favored to be dry and mild as the upper trough departs to the east. The remainder of the week has trended much drier and warmer as ensembles advertise high pressure expanding across the region. Low 10-30% chances of rain and thunderstorms are still in the forecast for midweek as moisture beneath the ridge overspreads the region, but are limited to the eastern Sierra from the Tahoe Basin southward. Elsewhere, a warming trend will culminate in daytime highs in the upper 70s and 80s between Tuesday and Friday. Thursday is favored to be the warmest day of the week with lower W NV valleys flirting with 90F highs. The prospect of cooler, windier, and showery weather increases next weekend as guidance hints at a return of PacNW troughing of some variety, but uncertainty is rather high at this extended range.

-Salas

AVIATION

SW FL100 winds will increase to 30-35 kts through 15Z this morning, presenting LLWS concerns at KTRK-KTVL-KMMH and mountain wave turbulence from the Sierra crest eastward into far W Nevada. S-SW surface gusts are expected to increase to 25-35 kts arrive after 19Z. Gusty winds may produce areas of blowing dust in the afternoon, possibly reducing visibilities at KHTH-KNFL-KLOL. At KRNO and KCXP/KMEV, a dry frontal passage will shift surface winds to W/NW after 23Z, posing additional LLWS impacts as the front moves through. Weakening winds aloft and at the surface should mitigate any LLWS and mountain wave turbulence issues by 06Z.

Chances of showers and thunderstorms increase to 30-60% this afternoon near the Oregon border, otherwise VFR conditions will prevail today.

-Salas

FIRE WEATHER

A dry frontal passage will produce a broad swath of 30-40 mph S/SW gusts this afternoon across the Sierra Front, and Mono and Mineral counties. RH reductions of 10-20% will be focused from valley and midslope areas of Mono County into S.Lyon and Mineral counties where 2-5 hours of critical fire weather conditions unfold this afternoon. While afternoon RH will be sub/near-critical across the Sierra Front and portions of west-central Nevada, humidity will be low enough (20- 25%) to warrant elevated fire concerns across these areas today. Winds shift to a more westerly direction in the wake of the frontal passage in the late afternoon and early evening.

Fortunately, nighttime recoveries will be moderate to good (up to 50- 80%) Sunday tonight into Monday morning. However, the exception to this will be across of the Chalfant Valley and other lower elevations near the Mono/Inyo Co border where RH struggles to exceed 40%.

-Salas

REV Watches/Warnings/Advisories

NV...Lake Wind Advisory from 11 AM this morning to 11 PM PDT this evening NVZ001>004.

CA...Lake Wind Advisory from 11 AM this morning to 11 PM PDT this evening CAZ071>073.