414
FXUS65 KREV 141004
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
204 AM PST Tue Jan 14 2025

.SYNOPSIS...

* A chilly morning will give way to a milder afternoon, with breezy
  northeasterly winds continuing along and west of Sierra ridges
  throughout the day.

* By Wednesday, lighter winds and valley inversions will settle in,
  resulting in cold nights and moderately warmer afternoons.

* This weekend, a cold front may bring another round of gusty
  northeast winds and cooler temperatures. The chance of light
  snow showers with this system is low, around 15% or less.

&&

.DISCUSSION...

Today:

* Gusty east-northeast ridge winds will peak this morning, with
  crest gusts reaching 50-60 mph. Daytime highs will rise into the
  40s, while lows this morning will fall into the teens and low-20s,
  with single digits in the coldest valleys of the Sierra.

WednesdayThursday:

* By late tonight, a shortwave ridge builds, bringing lighter
  winds and valley inversions through Thursday. Inversions will
  limit vertical mixing and ventilation, keeping valleys cold
  overnight, though daytime highs will return closer to seasonal
  normals. Mid- and upper slopes (above 7000 feet in the Tahoe
  Basin and 8500 feet in Alpine and Mono Counties) will warm more
  due to the dry airmass aloft.

FridaySaturday

* A weekend trough is expected to track over the Great Basin, with
  most models indicating that the bulk of moisture and cold air
  will remain east of the region. However, a slight westward shift
  could introduce a 5-15% chance of light snow showers for the
  eastern Sierra and western Nevada on Saturday, with minimal
  liquid amounts below 0.05". Anticipated impacts include
  increased breezes, gusty northeast ridge winds, and below-normal
  temperatures. The stronger winds may help erode inversions,
  improving mixing and ventilation. As ensemble guidance shows
  significant variability, further forecast adjustments are
  likely.

Next Week:

* Ridging will likely reestablish after the weekend, limiting storm
  potential through midweek.

Late January Trends:

* Long-range guidance hints at a few weak to moderate systems by
  late January, but confidence remains low. The pattern will be
  monitored for potential changes.

-Johnston

&&

.AVIATION...

Through 06Z Wednesday:

* Gusty east-northeast winds along Sierra ridges will persist into
  this evening. Winds at FL100 are expected to range from 30-40 kts,
  leading to increased turbulence particularly for areas west of the
  Sierra crest.

Mid-to-Late Week:

* Winds will diminish as high pressure sets up, creating inversions
  and cold overnight conditions. While the dry airmass will
  dominate, light frost may form on aircraft surfaces during the
  night, and freezing fog is possible in low-lying locations such as
  KTRK.

This Weekend:

* A weak cold front may bring another round of strong northeast
  winds, with the strongest impacts expected along ridge tops and
  higher elevations. There is also a low-end chance (less than 15%)
  of snow showers.

-Johnston

&&

.REV Watches/Warnings/Advisories...
NV...None.
CA...None.

&&

$$