textproduct: Reno

KEY MESSAGES

* Colder temperatures arriving this morning, with lighter afternoon winds accompanying increasing shower chances.

* Valley rain showers and snow on the highest peaks possible through Tuesday morning.

* A gradual warming trend resumes starting Tuesday, with dry conditions and light afternoon breezes returning as well.

DISCUSSION

Current infrared satellite reveals an influx of moisture streaming in from the south associated with the remnants of Tropical Storm Rachel. This feature is interfacing with the frontal passage that is bringing the colder air from the northwest. The result has stalled the northerly trough from its eastward progression, which will impact the weather outcomes for the next couple days. Since the source regions for each of these features is contrasted in both temperature profile and moisture profile, their interactions will dictate just how much colder we get, and how much moisture we can expect from this tropical system. The current position of the moisture plume extends from just south of the Sierra Mountains to Utah and Wyoming. This is near enough to us that we can expect some showers and mountain snow out of this, but there is still quite a bit of uncertainty in model discrepancy, leading to low confidence for some forecast details. For instance, earlier NBM runs had a 10-25% chance for up to and inch of snow at Tahoe lake level, now showing no accumulations for that area. What we can say is that there is a 20-50% chance to see wet stuff falling from the sky today across the Sierra and Sierra Front, with 30-60% chances for precipitation over the far eastern reaches of Pershing and Churchill counties, an area that is much closer to the main plume of atmospheric moisture. While we are expecting light snow on the highest peaks of the Sierra today, amounts will be limited to up to an inch through early Monday morning. With snow levels hovering around 6500-7500 feet early Monday morning, there could be snowflakes in the air for many Sierra communities. Snow levels will rise to 7000-7500 feet Monday afternoon, as stronger showers depicted in CAMs glide southeast along the Sierra through Monday into Monday evening. The timing of these showers in consideration with sunset on Monday evening will be the difference maker in the forecast for snow amounts. If the showers wrap up and move eastward in advance of sunset and the tumbling snow levels to around 6000-6500 feet, snow accumulations will be on the lighter side. If the showers intensify around sunset, it is a better setup to accumulate measurable snow. For now, there is a 20-40% chance to see up to 4 inches of snow on the top of Mt. Rose, along Tioga Pass or at the top of Mammoth Mountain. US-395 south of US-50 may see variable conditions from dry pavement to 2 to 3 inches of snow along the higher terrain.

Once we clear the showers out to the east for Tuesday, the sunshine will work to start a gradual warming trend along with drying conditions and a return to light afternoon breezes. HRICH

AVIATION

* Clouds and showers will increase today, with chances 20-40% for precipitation for all terminals. Sierra terminals may see snow showers tonight into Monday morning, but amounts will be light. Afternoon wind gusts will approach 15-20 kts today. HRICH

REV Watches/Warnings/Advisories

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