textproduct: Reno

KEY MESSAGES

* Periods of rain and mountain snow expected today and tonight with isolated thunderstorms in the afternoon.

* Showery weather continues Sunday into early next week with afternoon thunderstorms possible.

* Drier and warmer weather favored late next week.

DISCUSSION

A somewhat complex weather pattern unfolds today as a deepening upper trough to our north sharpens a deformation zone extending from a weak low approaching from the southwest. These features will focus greatest weather impacts across two areas today: 1) Lassen Co/the Surprise Valley into N Washoe and W Pershing Co, and 2) areas south of US-50.

In the northern area (NE CA/far NW NV), ample surface heating and midlevel height falls should yield enough instability to support a low to moderate likelihood (10-30% chance) of thunderstorms in the afternoon. Occasional lightning and gusty outflow winds will be the primary hazards with any mature storm. In the evening, a cold front will drop south of the Oregon border, delivering heavier rain and mountain snow (above 5500 feet) to far N Lassen County. Snowfall should be light, but highest peaks in Lassen County have a 20-40% of receiving 2 inches or more by Sunday morning.

Areas south of US-50 will feature a more steady form of rain and snow today, owing to stronger forcing for ascent within the deformation zone. Snow levels in Alpine and Mono counties begin around 8000 feet at the onset of precipitation, falling to 6000-6500 feet overnight. Snowfall totals by Sunday morning along the higher terrain of Alpine and Mono County will most likely vary from 3-6 inches with a 20-40% chance of exceeding 6" locally. Be prepared for slick roads along snow-prone stretches of US-395 in Mono County where there is a 20-40% chance of 2" or more. Meanwhile, the White Mountains are favored to be the big snowfall winner with this storm as there is a moderate to high likelihood (40-80% chance) of seeing 6-10 inches of snowfall. Elsewhere, expect periods of rain with a low 10-15% chance of thunderstorms. Additional rain and mountain snow showers are expected Sunday with isolated thunderstorms possible in the afternoon. There is better potential for snow/snow pellet showers near Tahoe on Sunday, so be prepared for slick/wet roads in the mountains. A persistent troughing will maintain daily shower chances into early next week, followed by drier and warmer conditions from midweek onward.

-Salas

AVIATION

Main weather concerns today will be increasing rain and mountain snow showers with isolated thunderstorms possible in the afternoon. Shower chances are highest at KMMH (~80%), resulting in periods of MVFR conditions and mountain obscuration. There is also a 15% chance of thunderstorms this afternoon at KMMH. Elsewhere, shower chances vary from 20-40% for all other terminals with a 15-20% chance of thunderstorms at KSVE.

-Salas

REV Watches/Warnings/Advisories

NV...None. CA...None.