textproduct: Reno

KEY MESSAGES

* Breezy winds overlap with low humidities across northern Washoe County, bringing elevated to critical fire weather concerns this afternoon. * Temperatures peak today, bringing areas of Moderate to locally Major HeatRisk across western Nevada.

* A monsoon moisture surge starting Sunday will bring increased chances for showers and thunderstorms next week into next weekend.

DISCUSSION

Today's temperatures will be the hottest over the next several days, with highs reaching into the triple digits across western NV valleys, Chalfant Valley, and near Honey Lake. Our upper level pattern remains on track with a high pressure over the Four Corners region to our ESE and a low pressure system in the Pacific NW. 700mb temperatures today over western NV range from 15-18C, which if mixed down, means high temperatures will likely range from 99-104F. A Heat Advisory still remains in effect today for Pershing, Churchill, Mineral, and Lyon counties because of this heat, so be sure to carry some water with you today!

Being on the western side of the high pressure, robust southerly flow aloft will drag a fair amount of subtropical moisture over our CWA over the next few days starting Sunday. Fortunately, there are a few shortwave troughs that are off the West Coast that are competing with this high pressure. For the first half of this week through Tuesday, the high pressure dominates and draws up that moisture from the SSE, allowing any storms to thrive across western NV and northeast CA. But by Wednesday, the shortwaves appear to win out and switch the flow aloft to more of a SW flow, drawing in much drier air from off the coast of SoCal. This will likely shut off or strongly inhibit storm development later in the week. Once we get to this upcoming weekend though, we could see the high pressure regain it's dominance over the Desert Southwest and start pulling up more subtropical moisture again.

That being said, any storms that form on Sunday will likely be on the drier side and have more of a wind threat associated with them. 0-3km lapse rates range from 10-10.7 degC/km, fast storm motions of 20+ kt, and surface RHs 10-15%. DCAPE values from the latest CAMs out in the Basin and Range are between 1000-1200 J/kg, indicating wind gusts from outflows could easily get to 45-55 mph. Then on Monday, western NV is able to generate more potential energy from the influx of low-level moisture. The main concerns then shift to small hail, gusty outflow winds, and possible flash flooding if storms start to train. The main area of concern for these storms remains south of I-80, though portions of northeast CA and north of I-80 can see some lighter showers and occasional lightning strikes. Much of the same on Tuesday for all the same areas. Then by Wednesday, the dry air dominates and we end up with a 10-15% chance of showers and thunderstorms in Mono County. We'll have more detailed information as these storms get closer in time, but for now just be aware of the upcoming weather hazards early this week!

-Justin

AVIATION

VFR conditions continue today with mostly clear skies for most of the day. Towards this evening, a layer of upper level SCT-BKN clouds moves in. Typical westerly winds this afternoon with gusts up to 15-25kt for all terminals.

Thunderstorm chances return to the southern Sierra, KMMH, as early as Sunday afternoon. More widespread potential for thunderstorms and showers arrives Monday and Tuesday with a monsoon moisture surge.

-Justin

FIRE WEATHER

* Breezy winds gusting 25-35 mph across northern Washoe County, Surprise Valley, and northern Lassen County will overlap with 7-12% RH this afternoon for roughly 1-5 hours this afternoon. Due to this, we're anticipating elevated to near critical fire weather conditions.

* A monsoon moisture surge forecast for next week from Sunday into Tuesday will usher shower and thunderstorm chances back into the Eastern Sierra and western Nevada, along with much of the Southwest US. First round of storms Sunday will likely be on the dry side with the potential for starts outside of wetter rain cores, but storms will quickly become quite wet Monday into Tuesday with a higher heavy rain risk.

-Edan /Justin

REV Watches/Warnings/Advisories

NV...Heat Advisory from 11 AM this morning to 8 AM PDT Sunday NVZ001- 004.

CA...None.