Mammoth Mountain

000
FXUS65 KREV 312041
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
141 PM PDT Sat Oct 31 2026

.KEY MESSAGES...

* A Pacific storm will bring rain, mountain snow and travel impacts, 
  and thunderstorm chances through Sunday morning. 

* Monday will be warmer and drier, with a return of increased winds 
  and showers around midweek.

* Dry weather is favored after the middle of next week, with a 
  potential return of unsettled weather around Veteran's Day.

&&

.DISCUSSION...

Rain and high elevation snow will remain light and sporadic during 
the afternoon, with a low 10-20% chance of isolated thunderstorms 
along the E Sierra and portions of W Nevada. Showers become more 
widespread during the evening and overnight hours, greeting 
Halloween festivities with wet, unpleasant weather. Be sure to make 
your evening plans accordingly, especially if traveling through the 
Sierra.

A bulk of the rain and snow will fall overnight, with heaviest 
snowfall rates of 0.5-1"/hours along the Sierra (above 7000 ft). 
Highest peaks in Alpine and Mono County may even see snowfall rates 
in excess of 1"/hour at times. Initially, snowfall and subsequent 
travel impacts will be confined above 7000 ft, but lowering snow 
levels will allow snow down to around 6000 ft Sunday morning. As 
such, greatest snowfall totals of 4-8" (up to 12" locally) will 
favor higher Sierra terrain, but light accumulations of a trace to
3" will be possible between 6000 and 7000 ft -- including Donner 
Pass and stretches of US-395 in Mono County. Be prepared for 
slick, snow-covered roads if traveling around/across the Sierra 
tonight or Sunday morning. 

One notable change to the forecast is that Sunday morning's snow 
levels have trended higher in latest blended guidance, which 
suggests rain-snow lines only fall as low as 5500 ft. Thus, valley 
floors will likely just see rain with this storm. Foothill areas may 
still see snow falling -- or at least a rain-snow mix -- but very 
little to no accumulation is expected. Rain and snow will gradually 
clear out to the east as the morning progresses, but there is a 10-
20% chance of lingering showers south of US-50 Sunday afternoon. 

Transient high pressure will deliver warmer and drier weather Monday 
before another Pacific storm increases the potential for gusty winds 
and showers Tuesday into Wednesday. Looking ahead, ensembles favor a 
period of dry and mild weather after the middle of next week, but 
signal a return of wet, unsettled weather around Veteran's Day.  
  
-Salas

&&

.AVIATION...

Low clouds and spotty -SHRA will maintain mountain obscuration 
impacts and brief periods of MVFR conditions at all area terminals 
through the afternoon. Thunderstorm chances increase to 10-20% in 
the afternoon, although KTRK-KTVL and KRNO-KCXP-KMEV have a 
relatively higher likelihood of t-storm impacts through around 02-
04Z.

Showers increase in coverage and intensity after 00Z this evening, 
resulting in longer stints of MVFR conditions and mountain 
obscuration through Sunday morning. Rain may briefly become a rain-
snow mix after midnight at KTRK and KTVL, but shower activity should 
be wrapping up by then so any reductions to IFR conditions will be 
brief. At KMMH, rain will become a rain-snow mix -- or perhaps all 
snow -- as early as 04Z, creating periods of IFR conditions through 
Sunday morning. A dusting of snow is possible on the KMMH runway by 
sunrise Sunday morning.  

Showers will taper off through the morning hours Sunday, with 
additional light showers possible at KTVL and KMMH Sunday afternoon. 
Elsewhere, expect VFR conditions to prevail Sunday afternoon into 
Monday. 

-Salas

&&

.REV Watches/Warnings/Advisories...
NV...Winter Weather Advisory until 7 AM PDT Sunday NVZ002.

CA...Winter Weather Advisory until 7 AM PDT Sunday CAZ072-073.

&&

$$