Bieber, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

574
FXUS65 KREV 180852 CCA
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
1246 AM PST Thu Dec 18 2025

.KEY MESSAGES...

* Wet and windy pattern commences this weekend, lasting into much
  of next week. Expect impacts to holiday travel.

* Good potential for heavy rain Sunday with rises on creeks and
  rivers, with a non-zero risk of heavy mountain snow Christmas
  Eve and Christmas Day.

* Dry and with gusty winds most areas today, with light showers
  and stronger winds tomorrow.

&&

.DISCUSSION...

* Impressive plumes of moisture coming off the Pacific into the
  Sierra over the next 5-7 days, with Sunday and Christmas Eve/Day
  the days to really watch with 30-60% chances of at least
  moderate atmospheric river conditions (IVT > 500) making it into
  the Sierra foothills, per CW3E charts. QPF amounts have trended
  up especially for Sunday-Monday and Wednesday compared to NBM
  guidance 24 hours ago. Snowfall trends mid/late next week are up
  but only slightly. Wind potential has ticked up for Friday but
  more notable rises for Sunday vs models 24 hours ago.

* Main unknowns are how far south the heavy rains will go this
  weekend before pivoting back north Monday-Tuesday. Tahoe Basin
  up into Lassen has the best chance of potential impacts from
  heavy rain and rising creeks/rivers. Also how quickly will the
  high rain- snow lines this weekend fall next week in time for
  the Christmas Eve/Day precip peak. That will dictate heavy snow
  potential in the Sierra and even down into the foothills of W
  Nevada around the holiday. 25th and 50th percentile snowfalls
  for mountain communities are zero but 90th is 7-15" each day
  Wednesday-Thursday for places like Tahoe and Mammoth Lakes.

* Can`t forget about winds in this pattern. Friday looking rather
  breezy with 50-80% odds of seeing gusts over 45 MPH along Hwy 395
  communities from Mammoth to Reno and up into NE California. Sunday
  is another day where if we see periods of shadowing, the winds
  could kick up with 30-60% chances of those 45 MPH gusts at times.
  Obviously the Sierra ridges will be howling, with 700mb winds
  projected near 60 knots in the ICON deterministic model, so that
  would easily yield 100+ MPH gusts for the higher terrain Friday
  and again Sunday. Even today 700mb flow is near 50 knots so ridges
  will be breezy.

* We`re entering a busy holiday travel period. Factoring in wind,
  snow, and rain potentials - Saturday and Tuesday probably have
  the best travel conditions. I`d probably stay away from Sunday
  and Wednesday/Thursday due to heavy rain and snow risks,
  respectively.

* The snowpack is in a sorry state not just in the Sierra but
  across much of the west. We`ve had precip just not snow. NRCS
  SNOTEL data showing the Eastern Sierra at or near record lows
  for this time of year going back to at least the early 1980s.
  The forecast pattern mid-late next week does allow for more cold
  air to drop in with a deepening trough, such that any storms
  Tuesday onward should have better snow potential for the
  mountains. NBM showing the rain to snow cross-over at Donner
  Pass and Mammoth Lakes is Monday evening or Tuesday morning
  respectively, where snow is favored over rain in NBM
  probabilistic guidance. But, one concern is it`s never really
  "all snow" even Wednesday & Thursday - e.g. 55-65% chance of
  snow p-type but 15-30% chance of rain...

-Chris

&&

.AVIATION...

* Main aviation weather issues next 24-36 hours center on wind,
  with a strong W/SW flow aloft spreading across the region
  Thursday & Friday. 700mb/ridgetop flow nearing 50-60 knots in
  latest high resolution models.

* For sure we`ll have periods of LLWS for all airfields in the
  Sierra and far W Nevada including RNO. Mountain wave turbulence
  is also expected Thursday and Friday east of the Sierra.

* How much of this flow mixes down to the surface is the main
  uncertainty. NBM guidance showing 30-50% chance of gusts over 30
  knots on Thursday between 21z-03z, with 70-90% chance on Friday at
  RNO/CXP/MEV, TRK/TVL, and MMH.

* A short lived wave of precip is also likely to affect flying
  conditions on Friday during the day. Mainly in the mountain
  areas from SVE to TRK/TVL with periods of MVFR-IFR in rain.

-Chris

&&

.REV Watches/Warnings/Advisories...
NV...Wind Advisory from 7 AM Friday to midnight PST Friday night
     NVZ005.

     Lake Wind Advisory from 4 PM this afternoon to 4 AM PST Saturday
     NVZ002.

     Lake Wind Advisory from 7 AM Friday to midnight PST Friday night
     NVZ004.

CA...Wind Advisory from 7 AM Friday to midnight PST Friday night
     CAZ070-071.

     Lake Wind Advisory from 4 PM this afternoon to 4 AM PST Saturday
     CAZ072.

&&

$$