textproduct: Reno

KEY MESSAGES

* A quick-moving low pressure system will bring gusty winds and increased chances for light rain/mountain snow showers today.

* Dry and mild weather prevails after Tuesday with temperatures trending warmer through the week.

DISCUSSION

For today, model guidance shows a Pacific upper low moving across N CA this afternoon and into N NV tonight. There is also quite a robust upper jet (around 100 kts at 250 mb) wrapping around this low and moving over the Sierra this morning. With these increased winds aloft, they will mix down during the day allowing for Sierra ridgetop winds to gust up to around 60-80 mph out of the southwest through the afternoon. These strong winds expect to also mix down into eastern Sierra valleys and along the Sierra Front, with surface gusts up to 25-35 mph, potentially reaching 50 mph in wind-prone areas. A Lake Wind Advisory is in effect today for Lake Tahoe as well, with lake winds gusting up to around 30 mph bringing choppy and hazardous lake conditions through this afternoon. Keep these winds in mind if you have travel or recreational plans for today.

As for precipitation concerns today, the 06Z run of the RRFS projects light rain and mountain snow showers generally moving west to east across the region during the afternoon and evening hours as the low pressure system passes through. The latest timing on these shower chances begins in NE CA and the Tahoe region around 1-2 PM PST, before spreading into the Sierra Front and Eastern Sierra around around 3-4 PM, then moving into the NV Basin and Range around 5-6 PM, and finally departing the region around 9 PM. Sierra and NE CA precipitation chances will be around 40-80% while the remainder of the region generally sees ~15-30% chances. Accumulations continue to look light as QPF values range between a trace and 0.2 inches, with the higher amounts at the Sierra crest. Snow levels today generally will be around 6500-7500 ft in the Tahoe region and 7000-8000 ft in Mono County. Snowfall amounts look to be mostly little to none in areas that see snow showers, with the exception of the Sierra crest having a 40-70% probability of 1+ inches of snow by this evening. Donner Pass has a 15-30% NBM probability of 1+ inches of snow as well. Road going over the Sierra could be slick due to this snowfall, so use caution if traveling through the area. Overnight low temperatures will drop once again in the wake of these showers, with Sierra communities seeing lows in the mid teens to middle 20s and W NV lows being between the upper 20s and mid-30s.

On Wednesday, forecast guidance projects the upper low departing to the east with a ridge moving over the area. This ridge is briefly flattened by a weak trough passing through the NW CONUS on Thursday, but it begins to redevelop going into the weekend. This signals dry weather for the remainder of the week and through the weekend. Daytime high temperatures cool by a few degrees on Wednesday in W NV, but temperatures trend warmer across the entire region Thursday through the weekend. Currently, forecast high temperatures on Sunday for NE CA and W NV valleys are in the mid-60s to around the 70 degree mark with highs in Sierra communities ranging between the lower and mid-60s. The latest run of the NBM then shows precipitation chances returning next Tuesday, which could be the start of a wetter weather pattern for midweek. -078

AVIATION

Increased winds and light rain/mountain snow shower chances are expected in the region today, with Sierra ridgetops gusting up to around 60-70 kts causing potential mountain wave turbulence and LLWS along and east of the Sierra. The window for precipitation still looks to be between 03/22Z-04/03Z with showers generally moving west to east across the region. Area terminals could see brief periods of MVFR conditions if a shower occurs nearby. Not anticipating much if any snowfall accumulation at Sierra terminals with snow levels forecast between 6500-7500 ft. KTRK could see freezing fog developing between 04/04-18Z, but not enough confidence to add to the TAF at this time. Drier conditions are expected going into Wednesday and through the remainder of the week. -Justin/078

REV Watches/Warnings/Advisories

NV...Lake Wind Advisory from 9 AM this morning to 4 PM PST this afternoon NVZ002.

CA...Lake Wind Advisory from 9 AM this morning to 4 PM PST this afternoon CAZ072.