textproduct: Reno

KEY MESSAGES

* A slight chance (10%) of showers and isolated thunderstorms across NE California and NW Nevada this afternoon, with similar chances areawide Sunday.

* Fog development for fog-prone Sierra valleys again tonight through tomorrow morning.

* Above normal temperatures prevail next week with cooler, unsettled weather possible next weekend.

DISCUSSION

Similar nighttime conditions should allow areas of fog to redevelop across N Sierra valleys early this morning. The Martis Valley and Sierra Valley remain favored for fog, although there may be pockets of fog in the Tahoe Basin and NE California. Fog becomes more patchy by Monday morning as drier air filters in. Be prepared for reduced visibilities in any fog banks, including the stretch of I-80 near Truckee.

Weak low pressure will be slow to depart the Pacific Northwest, maintaining low shower probabilities (15% or less) this afternoon and perhaps Monday. Otherwise, a notable warming trend begins today that culminates in daytime highs in the mid-upper 70s and 80s between Tuesday and Friday. Such temperatures yield a moderate HeatRisk in lowest W Nevada valleys from mid to late week, so be sure to stay hydrated and limit time in the heat. Also keep in mind that mountain lakes, rivers, and creeks are still running cold and swift (water temps in the upper 40s and 50s).

Typical zephyr breezes arrive each afternoon this week amid warming temperatures, but Wednesday afternoon may feature a minor uptick in winds (gusts of 25-35 mph) as a weak upper trough passes to the north. These increased breezes -- coupled with very warm temps, abundant sunshine, and critical RH reductions -- may support 1-3 hours of elevated to locally critical fire weather conditions Wednesday afternoon in W Nevada where cured/drying fuels reside.

The 00Z ensemble suite agree on a compact upper low entering the Pacific Northwest sometime next weekend, but differ on the timing and depth of this feature -- which isn't too surprising this far out. However, consensus on a more northerly approach suggests that wind will be chief concern opposed to showers/storms, at least initially. Latest blended guidance reflects this as odds of 30+ mph wind gusts sharply increase Friday (40-70%) and Saturday (60-90%), but highest shower chances of only 10-20% remain confined to near the Oregon border throughout the weekend. A trend towards a cooler, wetter outcome is certainly possible in coming days depending on the track/depth of the storm, but wind impacts to fire, recreation, and aviation seem much more likely at this point.

-Salas

AVIATION

Fog is expected to redevelop overnight at KTRK/the Martis Valley, lowering CIGS/VIS to IFR/LIFR conditions at times between 10Z and 16Z. Elsewhere, VFR conditions and light winds prevail through the morning.

An increasing cumulus field should develop along higher terrain this afternoon, possibly obscuring mountaintops. Otherwise, expect another day of widespread VFR conditions and breezy W/NW winds in the afternoon.

-Salas

REV Watches/Warnings/Advisories

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