textproduct: Reno

KEY MESSAGES

* West breezes increase the potential for fire growth this afternoon and evening for the Bug and Stallion Fires.

* Thunderstorms with heavy rain, hail, and strong outflow winds will expand northward Wednesday and Thursday. This will increase the threat for spots of Flash Flooding and new fire starts due to lightning.

* Cooler temperatures arrive Thursday with summer temperatures returning for the weekend.

DISCUSSION

Elongated area of low pressure along the west coast and high pressure near the Four Corners region will increase moisture into the Sierra and western NV the next couple of days. The low also provides instability for shower and thunderstorm development into Friday.

Hot temperatures today will continue to allow thunderstorms to produce strong outflow winds near 50 mph, hail, and spots of moderate to heavy rain from eastern Sierra into western NV south of I-80. High resolution models push a 50-55 mph area of outflow winds over the Carson Sink this evening, so there may be a large area of dust impacting Pershing and Churchill Counties after 4-5 PM.

Increasing moisture Wednesday and Thursday, along with the low pressure system and jet streak overhead boosts instability even with cooler temperatures arriving. This raises the threat for flash flooding for the eastern Sierra, and most of western NV near and south of I-80, including the Bug and Stallion Fires. Areas around the edge of the moisture surge from the Tahoe Basin northward to Lassen and northern Washoe Counties will have a mix of wet and drier storms opening the door for new fire starts due to lightning. If abundant cloud cover develops, strong thunderstorm and lightning activity may be muted, leaving the area under a large area of showers with wetting rains.

By Friday, thunderstorm activity diminishes as a drier southwest flow arrives for the weekend, but that may be a temporary break in the activity. Simulations bring another low near the California coast which may bring a mix of thunderstorms and/or dry-gusty winds back to the region as early as Monday-Tuesday. Brong

AVIATION

Shower and thunderstorm chances increase the next few days with increasing threat for heavy rainfall Wednesday and Thursday across western NV and the eastern Sierra.

For today, main concerns from thunderstorms are strong outflow winds to 35-45 kts, hail, and spots of heavy rain south of TRK to WMC from 21z today to 04z Wednesday. Simulations push strong winds over the Carson Sink, which may lead to dust and low visibility for NFL and LOL.

Smoke from the Bug and Stallion fires north of RNO will lower visibilities in and around the fire perhaps impact RTS (Reno- Stead), but west winds should keep conditions at 6 miles and up for RNO. Brong

FIRE WEATHER

Into this evening...Gusty and dry west to southwest winds of 20-30 mph this afternoon will bring another round of increased fire danger to the Bug and Stallion Fires. Pyrocumulus clouds will form above any strong bursts of fire activity on the Bug and Stallion Fires and may collapse back on onto the fires with strong and erratic winds this afternoon and evening. While thunderstorms with spots of strong outflow winds near 50 mph develop from the eastern Sierra, Carson City and Douglas County eastward into Mineral and Churchill Counties. Rainfall may be limited today.

Moisture increases Wednesday and Thursday leading to cooler temperatures and wetter thunderstorms with heavy rain and spots of flash flooding across much of the area including Bug and Stallion Fires. Lake Tahoe northward to Lassen County will be on the edge of the moisture increase with a mix of wet and dry storms there on Thursday, where we have issued a Fire Weather Watch as lightning will be more efficient at starting new fires. If abundant cloud cover develops, strong thunderstorm and lightning activity may be muted, leaving the area under a large area of showers with wetting rains.

Thunderstorm activity diminished Friday though a mix of wet and dry storm returns to western NV as moisture also decreases. The weekend looks dry, but not hot, with low pressure returning to the west coast which may lead to a return of thunderstorms and/or periods of dry and gusty winds for the start of next week. Brong

REV Watches/Warnings/Advisories

NV...Fire Weather Watch from late Wednesday night through Thursday evening NVZ458.

Flood Watch from Wednesday afternoon through Thursday evening NVZ001-003.

CA...Fire Weather Watch from late Wednesday night through Thursday evening CAZ270>272-278.

Flood Watch from Wednesday afternoon through Thursday evening CAZ073.