117
FXUS65 KREV 201719
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
919 AM PST Thu Nov 20 2025

.UPDATE...

Due to forecast snow levels lowering further, hovering around
5500 feet later this evening, Winter Weather Advisories have been
expanded and lowered in elevation. Advisories are now in effect
for the Greater Lake Tahoe Area and the Greater Reno-Carson City-
Minden Area above 5000 feet. The advisory elevation has also been
lowered to 5000 feet in southern Lyon and Mineral counties, and
the duration for the Mono County and southern Lyon and Mineral
counties has been extended an hour to 8 AM PST Friday. Expect
hazardous travel conditions through the Thursday evening commute
in all advisory areas.

&&

.PREVIOUS DISCUSSION... /issued 233 AM PST Thu Nov 20 2025/

KEY MESSAGES...

* A wintry storm system brings valley rain and mountain snow to the
  Sierra and western Nevada today through Friday morning.

* Dry conditions with cold morning low temperatures are in the
  forecast over the weekend.

* Looking ahead to the week of Thanksgiving, the weather for
  traveling looks good the early part of the week. Simulations are
  then pointing toward a potential colder storm during the weekend
  after the holiday.


DISCUSSION...

Today and Friday: When looking at the latest radar returns this
morning, the expected weather system has already been producing
light precipitation in NE CA. Snow levels currently look to be
around 5.5-6.5 kft, but are forecast to decrease during the day
until they become 5-6 kft by Thursday night. Forecast guidance
shows the weather-making upper low that is currently off the OR
coast progressing south-southeastward through the day while
staying west of the CWA. The latest CAM runs are showing precipitation
chances will spillover into W NV later this morning while
gradually spreading southward. Model guidance then shows the
valley rain/mountain snow chances increasing quite a bit to around
70-90% for areas closer to the CA-NV border by the afternoon
hours with areas closer to the OR border seeing chances beginning
to decrease. By the evening hours, the better precipitation
chances will be confined to south of I-80 continuing the north-to-south
tapering trend since the system will be moving along its
projected SSE track. Slowly, the precipitation coverage shrinks to
mostly being south of US-50 overnight before exiting the region
out of the south completely by Friday afternoon. As areas above 6
kft in Mono, Mineral, and Southern Lyon counties may see some
impactful snow totals, a Winter Weather Advisory continues for
later this morning into Friday. Please visit weather.gov/rev/winter
for more information on the advisory as well as forecast snow
totals including potential boom and bust scenarios. Other portions
of the Sierra Front may also see some measurable snow with this
storm that could have the potential increase if a band develops
and stays over the area for an extended amount of time. Will be
monitoring this in case an expansion of the advisory is needed.
Please stay tuned for forecast updates and use caution if
traveling today and Friday as roads may be slick due to the
expected wintry precipitation. Conditions look to be on the dry
side after the storm passes within the region for the remainder of
Friday.

The weekend: An upper ridge looks to build over the area on Saturday
and Sunday in the wake of the previous low. This setup aloft will
herald a dry pattern and light winds for the region. But it will
also allow for some chilly mornings as most of the region sees
temperatures in the 20s and lower 30s. Higher elevations in the
Sierra may even see lows dropping into the teens.

Thanksgiving Week: Going into the holiday week, the ridge pattern
continues aloft for most of the week including Thanksgiving permitting
dry conditions to persist. An exception is seen on Monday along the
OR border when a weak upper trough passes by the US/Canada border as
this could cause a low probability (~10%) for precipitation in
the afternoon, but there is low confidence at the moment of this
occurring. For the weekend following Thanksgiving, extended
guidance continues to show potential for a colder weather system
for the region with an upper trough developing in the western
CONUS. It is still to early to get into particular details with
this system being over a week out, but it something to keep an eye
on if you do have post- Thanksgiving travel plans. -078

AVIATION...

Light winds are expected this morning at all area TAF sites with a
winter weather system moving into the region causing MVFR ceilings
in NE CA and the Sierra. W NV terminals looks to stay with VFR
conditions until after 16Z when the better rain chances spillover
causing MVFR ceilings and visibilities. KTRK/KTVL continue to see
light snow chances this morning that may increase a bit, which
may lower visibilities down to IFR after 15Z. The snow chances
move down to spread down into the E Sierra later this morning and
into the afternoon causing IFR conditions at KMMH. The
precipitation coverage expects to begin to taper off from north to
south beginning this evening causing flight conditions to improve
at most terminals expect for KMMH which will continue to see snow
chances going into Friday morning. Models show precipitation chances
exiting out of the southern portions of the region around 21/18Z
followed by a dry period going through the weekend. -078

&&

.REV Watches/Warnings/Advisories...
NV...Winter Weather Advisory until 7 AM PST Friday NVZ001.

CA...Winter Weather Advisory until 7 AM PST Friday CAZ073.

&&

$$