textproduct: Reno

KEY MESSAGES

* Gusty westerly winds and low relative humidities have prompted widespread critical fire weather concerns for today.

* Temperatures cool off to near or slightly below early June seasonal averages Sunday through much of next week.

* Gusty winds and shower chances return early next week, then a return to drying out and warming up for late-week.

DISCUSSION

The dry cold frontal passage today has been kicking winds up already, strongest winds will continue through this evening. Gusts are already being observed 35-40+ mph, with ridge gusts creeping up to 55-60 mph territory. This timing will coincide with low relative humidity values, especially across the Basin and Range of western Nevada and portions of northeastern California. This combination, along with fuels that have become more receptive to spark, have prompted the Red Flag Warning for today through 11 PM tonight. See the Fire Weather section below for more details. Exercise caution today, including avoiding creating sparks with dragging trailer chains, target shooting or driving over dry vegetation.

Once this frontal boundary sweeps through the region, Sunday will be marked by cool northerly winds that will nudge temperatures across western Nevada a few degrees cooler than today's high temperatures. This downward temperature trend will continue into Monday, taking daytime highs closer to seasonal averages for the beginning of June. This reinforcement of cooler air will be supported by a secondary frontal passage, with a source region of the Gulf of Alaska. This suggests a more moist and cool airmass, which translates to the cooler temperatures and shower chances that are currently taking aim at the late Monday time frame for our area. In fact, recent modeling suggests the main time frame of concern for showers will be late Monday into early Tuesday. Some CAMs hint at lingering showers through Tuesday evening, but largely are out of the area by overnight Tuesday into Wednesday. Best chances exist along the Oregon border into the northern Sierra, where chances range 40-80%, but are concentrated to the overnight hours as mentioned. Various solutions have suggested other durations, but this trend has been depicted in the majority of 12z runs of both mid-range and CAM guidance. As for the winds associated with the early week FROPA, several context clues lean toward wind speeds similar to today's winds across the ridges, with similar to leaning slightly lighter for valleys. The evidence to this includes a robust jet streak associated with the next front, however the angle at which it approaches is less favorable, despite wind speeds contained within. Another consideration is the lack of thermal gradient due to overall cooling from today's first frontal passage. So, while 700 mb winds are on par for Monday to reflect today's ridge winds, the mixing of the winds to the valley floors looks limited. This will undoubtedly evolve in future iterations of the forecast cycle, so stay tuned as we work out the details.

Alrighty then, we will wish a fond farewell to showers and gusty winds by Wednesday, but we will notice light east winds developing on the backside of the front for late Wednesday into Thursday. By Friday, typical afternoon summer breezes return, along with a ridge that will advance from the Pacific that will bring back a heating and drying trend to our forecast. HRICH

AVIATION

* Gusty winds will be 35-40 kts to area terminals today, with FL100 westerly winds at 30-35 kts. This may induce pockets of LLWS and turbulence with mountain wave behavior. Winds are expected to taper after 06z Sunday.

* Showers are aiming to arrive around 06z Tuesday to KSVE, KLOL, KTRK and even KTVL. Chances range 15-20% for the above mentioned terminals through 12z Tuesday, then decrease to 5-10% as day breaks. Justin/HRICH

FIRE WEATHER

A Red Flag Warning is valid for this afternoon and evening across western NV and portions of northeast CA. The winds will be highest over western Nevada with a 75-95% chance for gusts to 40 mph. Elsewhere in the eastern Sierra, there's a 50-70% chance for gusts to 40 mph in valley locations with stronger winds for midslopes and ridges. Minimum RH ranges 9-13% in NV valleys and 10-18% in northeast CA for this afternoon.

Longer critical wind/RH overlap supports 8-10 hours of Red Flag conditions across western NV and into eastern Lassen County. Other areas such as lower Mono County valleys, including the Chalfant Valley, will also see a couple hours of elevated fire weather conditions.

-Justin/HRICH

REV Watches/Warnings/Advisories

NV...Red Flag Warning until 11 PM PDT this evening NVZ420-423-429-458.

Lake Wind Advisory until 11 PM PDT this evening NVZ001-003-004.

CA...Red Flag Warning until 11 PM PDT this evening CAZ278.

Lake Wind Advisory until 11 PM PDT this evening CAZ073.