textproduct: Reno

KEY MESSAGES

* Widespread minor HeatRisk with areas of Moderate HeatRisk in the Nevada Basin and Range is expected today as temperatures become milder going into the weekend.

* Thunderstorm activity continues today, bringing impacts to fire, recreation, travel and aviation.

* A warming trend resumes for next week, with a return of typical afternoon breezes.

DISCUSSION

Ongoing showers and storms this morning across northeastern California and northwestern Nevada are ahead of an incoming trough that will move onshore to the Pacific Coast into this afternoon and evening. As the heating of the day works to increase instability, we anticipate more storm activity through the day. Main storm threats today are to include potential for 60+ mph gusty outflows, frequent lightning and the possibility for up to 1" hail in any storm. For areas to the north of I-80, there is also another potential hazard, since the available atmospheric moisture is higher, there could be isolated flooding under wet storm cores. This could be mitigated by faster moving storm motions, but if many heavier showers encounter the same areas, we could see some isolated cases of flooding, such as streets or poor drainage areas. Chances for wetting rains will range 20-40%, this afternoon the focus will be for the area from Pyramid Lake, south to the Pine Nut Mountains, and from US-95 to the east to the Carson Range to the west. For this evening the focus shifts to the eastern Lassen County and northern Washoe County areas, with a chance ranging 20-50%. As of this writing, there are some clouds developing along the Sierra Crest, hinting at the active day ahead as we anticipate this activity to increase and storms to develop over terrain before moving due north. Several CAM guidance solutions show a late day storm complex developing over the Pine Nut mountains, then moving north into the Reno-Carson City-Minden area, before outflows from the complex start to move out toward the Carson Sink, where blowing dust may be lofted. As the outflows start to progress, we also anticipate there will be further storm development where outflow collisions occur. These secondary storm features can be difficult to model, but with DCAPE values ranging 1500-2000 J/kg, we expect strong gusty outflows to develop, especially over the Pershing and Churchill County area. The SPC has put us under a marginal risk for severe weather today, as well as a scattered dry thunderstorm fire weather outlook, which is owing to the faster storm motions producing potential bolts outside of storm cores. See the Fire Weather Discussion and Red Flag Warning for details of the fire weather risks for today.

Saturday we will see lingering showers along the Oregon border, with chances for showers around 15-20%, then decreasing through the day as the trough heads east. The region will also experience lower daytime highs, with temperatures in western Nevada hitting upper 80s to near 90 and the Sierra valleys in the upper 70s to low 80s. We will also see a return to typical afternoon summertime breezes. Then for Sunday, we rid ourselves of the showers, and the temperatures nudge up a couple degrees. A nice end to the weekend is in store!

For next week, summer heat returns, with highs climbing back to the upper 90s for western Nevada and upper 80s for Sierra valleys. Around midweek, shower chances look to return to the southern Sierra, but as of now chances remain low, around 15-20%. HRICH

AVIATION

* Ongoing showers this morning near KSVE and KLOL have cleared out this afternoon, with developing storms later for all western Nevada and Sierra terminals. Convective showers will develop around 19-21z, with a 30-70% chance for showers, and a 20-40% chance any given shower will become a strong to severe storm. Gusty outflows up to 60 kts are possible, along with potential for lightning and hail up to 1" as well as isolated heavy rainfall. Fast storm motions will limit flood potential, but storms may continue to develop over the same areas. Terrain obscuration, LLWS and turbulence may be present near storm cores. Sustained surface winds of 20-30 kts will also be present today through tonight.

* Lingering showers for Saturday will be likely along the northern borders of California and Nevada, with a 15-20% chance. Elsewhere, most terminals will return to VFR conditions for Saturday, with typical afternoon breezes of 15-20 kts. HRICH

FIRE WEATHER

Critical fire weather concerns continue today with thunderstorm chances and coverage increasing across the region. Antecedent hot and dry conditions with poor overnight recoveries have helped in drying fuels further which also increases fire danger.

Storms will again move quickly today toward the north-northeast once developed, with a mix of wet and dry storm modes. This increases potential for dry lightning strikes outside of wet storm cores as well as dry storms that produce more lightning than moisture. Gusty, erratic outflows of 60+ mph are possible, increasing the threat of rapid wind direction shifts. NE CA and portions of adjacent NV sees the thunderstorm potential begin in the morning before coverage spreads into W NV during the late morning/afternoon. Outside of storms, afternoon winds gusting up to around 25-35 mph are forecast within the region.

A Red Flag Warning is in effect today for W NV and portions of NE CA. See details in the Red Flag Warning product. HRICH/078

REV Watches/Warnings/Advisories

NV...Red Flag Warning until 11 PM PDT this evening NVZ458.

Red Flag Warning until 9 PM PDT this evening NVZ420-421.

Red Flag Warning until 11 PM PDT this evening NVZ423-429.

CA...Red Flag Warning until 11 PM PDT this evening CAZ270-278.