textproduct: Reno

KEY MESSAGES

* After a brief dip in temperatures through Monday, triple digit heat in western NV valleys returns for the rest of this week.

* Breezy winds through this evening will produce short periods of elevated fire weather concerns from northeast CA to parts of western NV mainly from I-80 northward.

* Current active fires producing areas of haze and smoke could reduce air quality in parts of western NV and northeast CA late tonight through at least Tuesday.

DISCUSSION

Today and Monday bring a temporary dip in temperatures for lower elevations behind a trough passage along the northwest US-Canada border. The other effect of this trough today will be afternoon- evening wind gusts edging up to 25-30 mph with a few gusts to 35 mph for areas near and north of I-80. This would lead to elevated fire weather concerns as afternoon humidity bottoms out in the single digits for western NV and parts of eastern Lassen County and 10-15% for areas north of Susanville-Gerlach to the OR border.

While highs Monday drop closer to early August averages in the mid-upper 90s for most valley areas (but remain near 90 for Sierra communities), one trade-off resulting from a northerly low-mid level flow will be increased areas of haze and smoke carried in from large active fires across Oregon. At a minimum, expect hazy skies to advance into more areas of western NV and northeast CA from late tonight through Tuesday. While the amount of smoke settling to the surface impacting air quality is less of a certainty, it would be a good idea to close windows later this evening and check airnow.gov for the latest air quality information during the next few days.

From Tuesday through next weekend, triple digit heat returns to most western NV valleys with prolonged peak heat (temperatures similar to yesterday) from Wednesday-Saturday as high pressure expands northward from the southwest US. Overnight lows are also poised to trend upward later in the week with HeatRisk rising to the Major category in more areas, so having a plan to stay safe (especially for those more sensitive to heat) during this longer heat period becomes more important.

The continued dry air mass with warm air aloft continues to keep conditions unfavorable for rain or t-storms, although later this week afternoon cumulus buildups are projected to return for areas south of US-50. For next weekend, PM shower/thunder chances edge upward to near 10-15% for southern portions of Mono and Mineral counties.

Longer range outlooks still attempt to spread the outer fringes of a monsoonal moisture push into parts of the eastern Sierra and western NV, but also hint at additional low pressure/trough activity affecting the Pacific NW. This would generally favor shower and t-storm potential for Mono-Mineral-Churchill counties with decreasing chances for areas farther north and west, where winds may increase. In addition, this pattern would displace the high pressure ridge away from CA/NV, with the majority of extended range guidance backing off from triple digit heat during the week of August 10. MJD

AVIATION

Widespread VFR conditions prevail today with W/SW of 20-25 kts in the afternoon. A weak frontal passage will deliver smoke from OR wildfires to areas near and north of Reno/Tahoe Monday morning, which may result in reductions to slantwise visibilities to KRNO- KCXP-KMEV Monday into Tuesday.

-Salas

REV Watches/Warnings/Advisories

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