textproduct: Reno

KEY MESSAGES

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

* Current active fires producing areas of haze and smoke could reduce air quality in parts of northwest and west central NV. * Typical afternoon winds will bring short periods of isolated elevated fire weather concerns.

DISCUSSION

Early August heat will have its first peak today with afternoon highs at least 100 degrees in most lower elevations and approaching 105 degrees along the US-95 corridor of west central NV where the Heat Advisory continues. A shortwave trough passage across the Pacific NW this weekend bring a slight increase in afternoon breezes each day with gusts 25-30 mph near and north of I-80. This would lead to elevated fire weather concerns as afternoon humidity bottoms out in the single digits to near 10%.

Behind this trough passage, temperatures ease back about 2-4 degrees Sunday across most elevations, with another slight dip Monday, as blended guidance shows a 20% or less chance of 100 degree highs across western NV communities. One trade-off of this break from the triple digit heat is potential for increased haze and smoke from ongoing fires across the Pacific NW spreading southward into northwest and west central NV during the day Sunday and Monday.

However, this temperature dip looks to be short-lived as a high pressure ridge over the southwest US attempts to rebuild northward into CA/NV. Latest blended guidance is favoring highs returning to triple digits starting Tuesday and continuing through the remainder of the week. While Thursday appears to favor the overall peak heat (highs similar to today), this could vary depending on the eventual position of the ridge, and whether shortwave trough passages across the Pacific NW are sufficient to suppress the ridge's northward expansion. Overnight lows are also poised to creep upward later in the week, so having a plan to stay safe during a potentially longer period of heat becomes more important.

The continued dry air mass with warm air aloft continues to keep conditions unfavorable for rain or t-storms, although by later next week afternoon cumulus buildups are projected to return for areas south of US-50. By the start of next weekend, PM shower/thunder chances edge upward to near 10% for southern portions of Mono and Mineral counties. Longer range outlooks hint at a further increase in monsoonal moisture across the southwest US with western NV on the fringe of this moisture push. While it's too soon to determine whether meaningful rain and t-storm chances return to the region by the second week of August, the majority of extended range guidance backs off from triple digit heat near and after August 10. MJD

AVIATION

* VFR conditions prevail through the weekend, with density altitude concerns at western NV terminals peaking today due to high temperatures at least 100 degrees. Daily SW-W gusts of 20-25 kts this weekend starting 20-22Z and tapering off between 02-04Z, with lighter afternoon winds Monday-Tuesday. MJD

REV Watches/Warnings/Advisories

NV...Heat Advisory until 8 AM PDT Sunday NVZ001-004.

CA...None.