textproduct: Reno

KEY MESSAGES

* Breezy to gusty winds continue today, allowing for elevated to critical fire weather conditions in Northeastern California and Northwestern Nevada.

* Isolated showers and thunderstorms are possible today in Western Nevada and the Sierra.

* A weather system on Friday brings increased chances for showers and thunderstorms and cooler temperatures to the region.

DISCUSSION

For today, model guidance shows the CWA between an upper ridge over the SW CONUS and an PacNW upper low over the coast of BC. This low is projected to slowly make its way eastward today, causing the southwesterly upper air flow over NE CA and NW NV to increase a bit. These quicker winds expect to mix down in the afternoon and allow for southwesterly gusts up to around 25-30 mph (up to 35 mph possible in these areas. With dry conditions prevailing here, there will be elevated to areas of critical fire weather today (see Fire Weather sections for more information). Please practice fire safety and refrain from activities that may cause sparks today.

While the aforementioned portions of the CWA look to stay mostly dry, the latest runs of the CAMs show around a 15-40% chance for isolated showers today for areas along and south of I-80 mostly between 2-10 PM with some chances lingering in the NV Basin and Range until midnight. There also looks to be around a 5-10% chance for a shower to contain lightning today. Forecast CAPE values look to be around 100-200 J/kg in some areas in the Sierra and Sierra Front today and DCAPE values still are over 1000 J/kg this afternoon, so outflow wind gusts up to around 45-50 mph could be possible with storms along with brief periods of heavy rainfall.

Going into Friday, forecast guidance shows the upper low making its way along the Canada/U.S. border and pushing the influence of the upper ridge away from the CWA a bit. This setup not only looks to push some cooler air in from the north, but it also looks to pump more monsoonal moisture into the region. As such, model guidance is showing it to be a cloudy day with increased chances for precipitation. The latest run of the NBM is showing a 40-80% chance for widespread showers through the day in the region on Friday. PW values look to be on the higher side (1+ inches), but this may just allow for the increased cloud cover. QPF values for Friday range between a trace and up to around 0.5 inches in the highest portions of the Sierra. While the increased cloud cover may inhibit some afternoon convection, there still looks to be a 15-25% chance for isolated thunderstorms in the region. Forecast CAPE values currently reach over 1000 J/kg in the NV Basin and Range on Friday, so there could be some strong storm potential. The WPC Excessive Rainfall Outlook shows a marginal (5%) risk for excessive rainfall for most of the CWA on Friday as storms will be capable of periods of heavy rainfall once again. Please watch for forecast updates as they become available, especially if you plan on traveling to the events in Black Rock Desert. Precipitation chances currently look to taper off going into Saturday.

With cooler air moving in and lesser heating from the expected cloud cover, daytime high temperatures are forecast to be around 5-10 degrees lower on Friday when compared to the prior days in the week. The NE CA and W NV valleys will have highs around the 80 degree mark while Sierra communities will be in the upper 60s to middle 70s range. Area temperatures do expect to rebound by a few degrees going through the weekend and into next week. Dry conditions look to be on tap at the beginning of the week, but there are some hints of precipitation possible by the middle of next week with another system. However, forecast confidence out this far is still quite low. -078

AVIATION

TAF sites look to see mostly VFR conditions today and tonight. Area winds will gust up to around 20-25 kts between 27/20Z-28/04Z, with portions closer to the OR border seeing gusts up to around 30 kts.

Forecast guidance shows around a 10-40% chance for showers between 27/20Z-28/06Z in W NV and the Sierra, with the higher end chances in Mono County. In addition, there is a 5-10% chance for an isolated thunderstorm within these shower chances. Not anticipating sub-VFR conditions today due to shower and storm chances, but will monitor conditions and amend TAFs if guidance begins showing otherwise. On Friday, a cooler weather system moves through the region, bringing increased cloud cover and a more widespread 40-80% chance for showers and thunderstorms to the area. -078

FIRE WEATHER

Elevated to areas of critical fire weather conditions are expected again today in far NE CA and far NW NV. SW winds gusting up to 25-30 mph (isolated pockets of up to 35 mph possible in wind prone areas) and minimum RH values between 8-20% are in the forecast in the afternoon for these areas. RH recoveries in these areas will improve slightly to around 35-50% on Thursday night. Elsewhere, there is around a 5-10% chance for an isolated thunderstorm embedded within a 15-40% chance of showers this afternoon. A cooler weather system on Friday brings increased chances (40-80%) for more widespread showers and isolated thunderstorms, which will reduce fire weather concerns for the region. -078

REV Watches/Warnings/Advisories

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