textproduct: Reno

KEY MESSAGES

* Patchy fog may reduce visibilities and create slick roads for this morning's commute in the eastern Sierra, especially near Truckee.

* Warm and dry weather prevails today and Friday.

* Chances of rain and mountain snow showers, thunderstorms, and gusty winds increase this weekend and linger into early next week.

DISCUSSION

Minimal change in the weather pattern and another night of clear skies should support localized fog/freezing fog in the eastern Sierra this morning. The Martis Valley/Truckee area continues to be favored for freezing fog, including the stretch of I-80 between Boca and Donner Lake. Webcam and satellite obs revealed that fog/low clouds were able to form on and east of Lake Tahoe yesterday morning, so there may be additional fog in the Tahoe Basin this morning. Be prepared for reduced visibilities and slick roads before fog mixes out around 9 AM PDT.

Warm and dry weather rounds out the work week as transient high pressure overspreads the region. Further drying and confluent flow aloft will continue to limit afternoon shower chances to 10% or less today and Friday. Respectively, daytime highs today will be in the low 60s and low 70s for Sierra and lower NE CA/W NV valleys, warming into the mid 60s and upper 70s Friday afternoon.

A compact, eastern Pacific low remains on track to bring increased potential for rain/mountain snow showers, thunderstorms, and gusty winds between Saturday and Wednesday. In general, shower chances begin to increase Saturday, peak/expand Sunday and Monday, before decreasing Tuesday and Wednesday. Thunderstorm activity follows a similar trend with greatest coverage/likelihood Sunday and Monday afternoons. Sunday appears to be particularly favorable for thunderstorms -- mainly in the Sierra and Sierra Front where odds are ~30% -- as low-levels moisten and large scale ascent overspreads the region. Furthermore, deep-layer shear weakens and becomes more easterly on Sunday, which is conducive for deeper vertical growth within upslope flow in the lee of the Sierra. This storm doesn't appear to be a major snowmaker by any means given that snow levels will be high, but light accumulating snow is possible along highest mountain peaks early next week. Warmer and drier weather returns towards the latter half of next week as low pressure shifts east.

-Salas

AVIATION

Redeveloping FZFG is expected to yield periods of IFR/LIFR conditions at KTRK/Martis Valley through 16Z. Otherwise, widespread VFR conditions and light east breezes prevail today and Friday.

-Salas

REV Watches/Warnings/Advisories

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