textproduct: Reno

KEY MESSAGES

* Gusty S/SW winds will continue this afternoon and Sunday, leading to critical fire weather conditions and recreation impacts.

* Isolated showers and thunderstorms are possible today in Mono, S Lyon, Mineral, and Churchill counties, diminishing Sunday.

* Seasonably hot temperatures will persist through the weekend with warmer temperatures and periods of moderate HeatRisk next week.

DISCUSSION

The synoptic pattern this weekend features a broad upper-level ridge centered over the central/southern U.S., with a belt of SW flow aloft extending across the Great Basin. Because of that SW flow, we're still on the edge of a monsoonal moisture surge over the Southwest and Intermountain West, with seasonably hot temperatures building over the Great Basin.

Deep vertical mixing and stronger southwesterly flow aloft will continue to produce gusty W/SW winds this afternoon and again Sunday. Widespread SW/W winds of 15 to 20 mph with gusts of 30 to 40 mph can be expected across much of northeast California and western Nevada. Specifically, the Greater Reno-Carson City- Minden Area, Surprise Valley/Northern Washoe County, and Lassen/ Eastern Plumas/Eastern Sierra Counties can expect gusts up to 40 mph this afternoon, and 35 mph Sunday. The Greater Lake Tahoe Area will also experience gusts up to 30 mph both days. These winds, coupled with low relative humidity values (as low as 5-15%), will contribute to critical fire weather conditions. Winds are expected to decrease slightly on Monday, generally remaining around 10-15 mph with 20-25 mph gusts.

Seasonably hot temperatures will prevail through the weekend. Today, highs in lower elevation valleys such as Reno, Fallon, and Hawthorne are forecast to reach 100-102 degrees. Mountain communities like Lake Tahoe and Mammoth Lakes will see highs in the low to mid-80s. Overnight lows will offer limited relief, ranging from the upper 50s to mid-60s in the mountains and upper 60s to low 70s in the valleys. A warming trend is expected to commence next week. Lower elevation valleys will see temperatures climb into the triple digits, with NBM guidance showing highs reaching 100-107 degrees by Friday for locations such as Reno, Fallon, and Surprise Valley. Mountain areas will also experience increasing heat, with highs in the upper 80s to mid-90s. Overnight lows will remain warm, providing minimal relief from the daytime heat. Moderate HeatRisk is anticipated across lower elevation valleys.

Mid-level moisture and weak instability, as indicated by the 12Z REV sounding (MUCAPE 175 J/kg, PWAT 0.64 inches), may support isolated showers and thunderstorms this afternoon. The highest chances for precipitation (10-20% POPs) are over Mono, S Lyon, Mineral, and Churchill counties this afternoon. Moisture is expected to scour out on Sunday, reducing shower/storm chances to 10% or less.

Next week, winds are expected to be lighter and more typical of afternoon breezes compared to the gusty conditions of this weekend, generally in the 10-20 mph range, which should mitigate fire and recreation impacts.

-Justin

AVIATION

VFR conditions will continue across the region, with only KHTH having a 20-25% chance for a thunderstorm this afternoon. Otherwise, W/SW winds will prevail with gusts up to 25-30kt this afternoon. These winds may yield minor LLWS this afternoon.

Sunday, winds ease up by 5-10kt, back to a more typical afternoon breeze, and drier conditions are expected.

-Justin

FIRE WEATHER

SW/W winds of 15 to 25 mph with gusts of 30-40 mph will overlap with minimum RHs of 5-15% for a 3-6 hour period this afternoon across portions of far NE California and NW Nevada, including the Biscar and Macy fires. A Red Flag Warning remains in effect until 9 PM PDT, but strongest winds arrive after 12 PM PDT. Nighttime recoveries will be moderate to poor in these areas each night, which may allow fires to actively burn overnight, especially in W NV where RH struggles to exceed 20-30%.

A few hours of critical wind/RH are expected Sunday afternoon across a similar area, but the duration/coverage should be more limited compared to today. We did go ahead and upgrade our Fire Weather Watch to a Red Flag Warning for Sunday though, due to the sheer dryness, even with marginal winds. A hot, dry, and breezy weather pattern remains in place next week.

-Salas/Justin

REV Watches/Warnings/Advisories

NV...Red Flag Warning until 9 PM PDT this evening NVZ458.

Red Flag Warning from 1 PM to 9 PM PDT Sunday NVZ420-458.

Red Flag Warning until 9 PM PDT this evening NVZ420.

CA...Red Flag Warning until 9 PM PDT this evening CAZ270-278.

Red Flag Warning from 1 PM to 9 PM PDT Sunday CAZ270-278.