Northstar California

000
FXUS65 KREV 300934
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
234 AM PDT Fri Oct 30 2026

.KEY MESSAGES...

* Chances of light rain and mountain snow continue through the day
  mainly for the Sierra and vicinity areas. 

* A storm system on Saturday and Sunday brings colder temperatures
  along with light valley rain, and mountain snow above 7000 ft.

* Drier and warmer conditions return by Sunday afternoon through
  mid-week next week. 

&&

.DISCUSSION...

Current radar imagery shows a band of light rain and light mountain
snow over Central CA and the western slopes of the Sierra. Most 
of it is being blocked at the crest with a few light showers 
spilling over to the eastern slopes of the Sierra and western NV. 
Rain amounts are very light or none at all. This is expected to 
continue through the morning hours per the HREF and REFS. Although
more spillover is expected later this morning especially for the 
Sierra and Sierra Front. Rain also develops in areas east of 
US-95, especially closer to far eastern Churchill/Pershing 
counties today. Activity will be more spotty this afternoon and 
evening, so expect breaks with the light rain in western NV, and 
the rain snow mix in the Sierra. Snow levels will be around 
7000-7500 feet, above those elevations a trace to 3 inches of snow
are possible through the evening hours today. Chances of 
exceeding 3 inches are 10-50%+ above 10 kft south of US-50, and a
10-40% of exceeding one inch above 7 kft.

The models are finally starting to align with better consistency
for a clearer scenario on Saturday and Sunday. The broad upper 
low off the PacNW generates a secondary low in the Eastern Pacific
and pulling a plume of warm and moist air which, merges with the 
colder and drier air from the northern system over California and
Nevada. This scenario has led to an increase in precipitation 
with snow levels starting around 7-8 kft Saturday and potentially 
dropping to 5 kft or lower by Sunday morning. The main area of 
concern will be in the Sierra above 7000 ft, where snow amounts 
of 3-6 inches are likely with a 10-40% chance of exceeding 6 
inches north of US-50 and 30-60% to the south of US-50 by Sunday 
afternoon. At Lake Tahoe level and US-395 in Mono county, there 
is a 10-50% chance of reaching 2 inches of snow by Sunday 
afternoon too. A Winter Weather Advisory remains in effect for the
Sierra for the above reasons. Checking with CalTrans and NDOT 
(for Mt. Rose Highway) for the latest road conditions is 
recommended as travel through these areas, especially the passes 
will be hazardous. 

Western NV and NE CA valleys will see mostly rain with a low 
(5-15%) chance of a wintry mix making it to valley floors on 
Sunday morning. The moisture is mostly leaving as the really cold 
air makes it in. So, a few snow showers amounting up to a trace or
a dusting of snow are possible by Sunday morning in the valleys.

By Sunday evening through Tuesday or Wednesday next week warmer 
and drier conditions are expected with an upper ridge developing 
in the region. Model uncertainty continues with the ending of the
precipitation on Sunday as some ensemble members keep showers in 
the area through Sunday night, albeit light. Then again with the 
approach of the next system sometime between Tuesday evening and 
Thursday, and a potentially subsequent system for the following
weekend. However, based on how guidance has behaved this week, I 
wouldn't put much trust in them until at least early next week.

-HC

&&

.AVIATION...

VFR conditions with brief periods of MVFR are expected through 
Saturday morning over western NV and northeast CA. The periods of 
MVFR will be due to -RA primarily reducing CIGs. VIS reductions 
should be minimal, except near the strongest showers. Rain 
chances are 5-30% through Saturday morning. For KTRK, KTVL and 
KMMH, expect periods of VFR and MVFR due to low clouds and 30%+ 
chances of -RA/-SN. Snow chances will be higher in the early 
morning hours, especially around sunrise. Little to no snow 
accumulations are expected. Mountain obscurations prevail through
the weekend. Periods of turbulence and LLWS are expected through 
this morning, then return again late this evening.

More valley rain and mountain snow is expected on Saturday and
Sunday with the next system.

-HC

&&

.REV Watches/Warnings/Advisories...
NV...Winter Weather Advisory from 8 AM Saturday to 7 AM PDT Sunday 
     NVZ002.

CA...Winter Weather Advisory from 8 AM Saturday to 7 AM PDT Sunday 
     CAZ072-073.

&&

$$