textproduct: Reno

KEY MESSAGES

* Isolated showers and thunderstorms return this afternoon near the Oregon border and parts of west central NV southward to Mono County. * Typical July warmth continues through midweek with breezy afternoon winds and lower humidity posing minor fire and recreation impacts.

* Hotter temperatures with Moderate to isolated Major HeatRisk arrive later this week and into the weekend.

DISCUSSION

Sunday's shower and t-storm activity was mainly confined to northeast CA/Surprise Valley and far northwest NV, with about 80 total cloud to ground lightning strikes and spotty wetting rainfall up to near 0.30". Elsewhere from the eastern Sierra to far western and west central NV, a swath of thicker mid-level clouds was accompanied by occasional very light rain showers and cooler high temperatures in the 70s for Sierra sites and 80s for lower elevations, but no lightning was detected.

For today, residual moisture and instability will allow for isolated afternoon showers and t-storms favoring two areas: 1) Surprise Valley/far northwest NV and 2) West Central NV (mainly Lyon/S Churchill/Mineral counties) and Mono County. With less organized forcing, storms that form today are more likely to be shorter duration, pulse-type cells with brief heavy rainfall, very small hail, and outflow gusts to 40 mph. A few storms could also be supported by low level convergence along the zephyr boundary east of Reno-Carson-Minden. The most likely time frame for today's convection is between 3-8 PM with a few stray cells as early as 1 PM or as late as 10 PM.

Without the thick cloud cover that spread across much of the region yesterday, temperatures today will rebound to near early July averages of lower-mid 90s for lower elevations and lower 80s for Sierra communities. Zephyr-type breezes are expected to be a bit weaker today, with gusts up to 25 mph.

From Tuesday through Wednesday, weak troughing along the west coast will bring drier air into eastern CA/western NV, essentially ending the threat for PM t-storms. Highs will be typical for July, mainly in the 90s for lower elevations and low-mid 80s near the Sierra with decent cooling overnight. Zephyr-type breezes with gusts 25-30 mph and brief gusts to near 35 mph combined with afternoon RH dipping into the single digits across western NV will produce elevated to locally critical fire weather concerns both days. A prolonged gusty wind event is not anticipated, but with the drier conditions including overnight RH recovery becoming more limited, it's important to remain fire-safe and avoid activities that could spark a fire in dry vegetation.

Later this week, the west coast trough lifts out and allows for a high pressure ridge to expand across the southwest US and into the Four Corners region. We'll see temperatures climb upward a bit on Thursday, with the heat peaking Friday and Saturday as triple digit heat returns to western NV valleys (with Moderate to isolated Major HeatRisk), while Sierra locations push into the upper 80s.

As we get to next week, a more southerly flow aloft over CA-NV will direct more moisture into the region. Cloud cover looks to increase starting Sunday, with a better chance for showers and t-storms returning Monday. Afternoon highs will ease back a bit but remain above average, while overnight lows trend upward a few degrees. There is potential for this type of pattern to persist into mid-July, but confidence is lower this far in advance. MJD

AVIATION

VFR conditions prevail at the main terminals through the upcoming week. Low chances for showers/t-storms linger this afternoon between 21-03Z, about 10-15% at KMMH and less than 10% at the other main terminals, but then drop to near zero at all terminals from Tuesday through late week.

Typical PM breezes are expected at the main terminals with gusts 20-25 kt most days between 22-04Z. Occasional gusts to 30 kt could occur Tuesday-Wednesday afternoons for the far western NV sites southward to KMMH. For KTVL/KTRK, winds this week will be a bit lighter. MJD

REV Watches/Warnings/Advisories

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