textproduct: Reno

KEY MESSAGES

* Gusty southwest winds today bring critical fire weather conditions and lake recreation impacts to parts of northeast CA, northwest NV.

* Showers and isolated thunderstorms continue across parts of the eastern Sierra and western NV today and tomorrow.

* Seasonal temperatures, overall dry conditions and afternoon breezes prevail for much of next week.

DISCUSSION

A few light showers persist early this morning over portions of the CWA. Most of this activity should be done by sunrise. However, more showers and thunderstorms are expected this afternoon over portions of western NV and the eastern Sierra. The main area of concern will be Mineral, and eastern Mono/Churchill/Pershing counties, where we have the highest chances of precipitation of 30-40%. However, storm chances remain at 15-25%. Therefore, expect scattered showers and isolated to scattered thunderstorms in the aforementioned areas. The main concerns with any storm will be gusty outflow winds to 40 mph, frequent lightning, periods of heavy rain with the strongest cells that could lead to flash flooding, and small hail.

Furthermore, the position of the upper ridge centered over the Desert Southwest and an upper trough moving inland into the PacNW will tighten our pressure gradient at the surface this afternoon leading to westerly gusts of 30-35 mph with isolated locations having a 30-60% chances of observing gusts to 40 mph over NE CA and NW NV including the Sierra Front. Lake Wind Advisories and a Red Flag Warning are in effect for this reason. For more about fire weather, please read the Fire Weather Section below.

By Sunday, the winds and our chances for showers and thunderstorms decrease as the upper trough pushes the ridge farther east towards the Southern Plains, which sets the plume of monsoonal moisture towards central and eastern NV. So, the best chance for precipitation will be in the NV Basin and Range. Winds will be typical for this time of the year.

For Monday and beyond, we remain under a sort of blocky pattern with the ridge retrograding back towards the Desert Southwest and a longwave trough persisting off the PacNW coast (occasionally sending shortwaves inland). This pattern leads to seasonal temperatures, afternoon breezes and generally dry conditions. However, the proximity to the monsoonal moisture plume could allow for isolated showers and thunderstorms in areas south of US-50. Plus, the incoming shortwaves have the potential to increase afternoon gusts every other day bringing back fire and recreation concerns throughout the week.

-HC

AVIATION

Mostly VFR conditions continue with mid to high level clouds. Mountain obscurations persist in the Sierra through 21Z-00Z this afternoon. SHRA/TSRA has a 10-40% chance to develop this afternoon for terminals south of Interstate 80, decreasing to 10-30% Sunday for KBAN/KHTH/KNFL/KLOL. Storms could bring periods of reduced CIGS and VIS. Gusty winds to 30 kts return between 20Z-03Z with some locations up to 35 kts. There is low potential for minor turbulence and LLWS after 00Z this evening.

-HC

FIRE WEATHER

Fire weather concerns return late this morning through the evening, as wind gusts increase to the 30-40 mph range across northeast CA, northwest NV, and the Northern Sierra Front. While humidity values aren't exceedingly low (minimums 10-18%), most of these areas did not receive much rainfall last week, resulting in a greater extent of dry vegetation where fire could spread more quickly when the winds pick up. Therefore, a Red Flag Warning continues in effect for these areas. So, be extra cautious and fire safe, avoid outdoor recreation or work activities that could spark any fires. From Sunday through next week, afternoon breezes continue but at lower speeds compared to Saturday. The next period to watch is next Tuesday or Wednesday, when winds potentially trend upward, while afternoon humidity decreases as a dry air mass settles in.

-MJD/HC

REV Watches/Warnings/Advisories

NV...Red Flag Warning from 11 AM to 11 PM PDT Saturday NVZ420-458.

Lake Wind Advisory from 11 AM to 11 PM PDT Saturday NVZ003.

CA...Red Flag Warning from 11 AM to 11 PM PDT Saturday CAZ270-278.

Lake Wind Advisory from 11 AM to 11 PM PDT Saturday CAZ071.