Mammoth Lakes, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

038
FXUS65 KREV 252107
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
207 PM PDT Thu Jun 25 2026

.KEY MESSAGES...

* Warm, dry, and breezy weather continues today with choppy lakes
  and isolated critical fire weather conditions this afternoon for
  W.Nevada.

* Critical fire weather concerns expected for W.Nevada due to gusty
  winds and dry conditions with a strong cold front on Friday and
  Saturday.

* Temperatures cool 10-20 degrees below average over the weekend
  with light showers possible Friday-Saturday.

&&

.DISCUSSION...

For today, forecast guidance depicts a generally westerly flow over
the CWA that begins to turn a bit more west-southwesterly late this
afternoon and evening as a PacNW upper trough begins to move down
into the W CONUS. With this pattern above, the region looks to see
one last day of above late June normal temperatures. W NV valleys
will experience highs in the lower 90s this afternoon with Sierra
communities ranging between the upper 70s and lower 80s. While dry
conditions will prevail through the rest of today, area winds expect
to increase in the late afternoon with gusts up to 25-35 mph that
will last through the evening hours. A Lake Wind Advisory remains
in effect for the rest of today for W NV lakes including Pyramid
Lake as choppy lake waters are expected. Sierra ridge winds also
look to gust up to around 60 mph through the night. With portions
of the W NV seeing relative humidity dropping down to the lower
teens to upper single digits in the afternoon, a few hours of
elevated to isolated areas of critical fire weather conditions
are expected this afternoon into the early evening. Low temperatures
tonight cool down to the upper 50s to lower 60s in W NV with NE
CA and the Sierra ranging between the lower 40s to the lower 50s.

For tomorrow, models have the trough moving over the CWA by early
Friday morning and remaining in the W CONUS through the day. With
this setup aloft, the first in a series of cold front passages looks
to move through on Friday. The region sees cooler daytime high
temperatures on Friday with W NV valleys in the middle 70s to lower
80s range and the Sierra communities in the middle 60s to lower 70s
range. According to the latest run of the RRFS, the front will allow
for a band of light showers to move through portions of W NV
generally north of I-80 during the early morning that will progress
into the remaining W NV portions of the CWA going through the rest
of the morning. Behind it going into the afternoon, there looks to
be around 20-40% chance for isolated showers north of US-50 with the
higher end chances around the Tahoe Basin. Within these showers,
there is a 10-15% chance for an isolated thunderstorm in the
afternoon though not anticipating these storms to be severe. QPF
values do not look to exceed 0.1 inches through the day though
locally higher amounts could be possible from a thunderstorm
producing a brief downpour. Winds increase on Friday with sustained
winds of 20-25 mph gusting up to 35-45 mph in the forecast bringing
another day of lake wind concerns as well as potential blowing dust
near W NV desert sinks and playas. Critical fire weather conditions
are also expected with these winds and thunderstorm chances on
Friday in W NV (please see the Fire Weather section and the Red Flag
Warning for more information). Overnight low temperatures drop to
the 40s and 50s with portions of the Sierra cooling to the middle to
upper 30s. Chances for showers near the OR border also increase up
to around 50-60% overnight with another approaching cold front.

Forecast guidance then projects the upper trough to remain over the
W CONUS on Saturday though having its axis pass over the CWA during
the afternoon hours. Chances for precipitation in N Washoe, N
Pershing, E Modoc and Lassen Counties will increase even more to
around 55-85% during the Saturday morning hours with a 10-15% chance
for isolated thunderstorms. By late afternoon and going into the
night, these chances will decrease to around 25-65% while
spreading south down to around US-50. The latest QPF values for
Saturday range from a trace around US-50 up to around 0.3 inches
in northern portions of Lassen County. Temperatures continue to
cool with the secondary cold front passage causing a chilly Saturday
night with lows in the 30s and 40s (some portions of the Sierra
dropping below freezing). Snow levels lower to around 6.5-7.5 kft
in NE CA as well which may allow higher elevations in the
northern Tahoe Basin and the Warner Mountains to see a dusting of
snow by Sunday morning. Mostly similar winds to those seen on the
previous day will allow for similar maritime impacts (Lake Wind Advisory
now continues through Saturday) as well blowing dust and fire weather
concerns. One difference from Friday winds is that ridge winds are
forecast to gust up to around 65-75 mph for the first half of the
day.

Well-below normal temperatures continue on Sunday with some lingering
morning shower chances in eastern Pershing and Churchill Counties.
Area temperatures then begin to rebound as they gradually trend
warmer going through next week with mostly dry conditions at least
through the middle of next week. -078

&&

.AVIATION...

VFR conditions are expected through the rest of today and tonight
within the region. Afternoon winds gusting up to around 25-30 kts
expect to subside by around 26/04-05Z. However, areas of mountain
turbulence and LLWS are in the forecast going into the night for
all TAF sites (with exception of KMMH) as FL100 winds of 35-40
kts are to be expected. A series of cold fronts will bring shower
and thunderstorm chances to the region tomorrow and Saturday along
with winds gusting up to around 35-45 kts (Sierra ridge winds up
to to 55-65 kts). LLWS and mountain waves may pose hazards on
these days with portions of the W NV Basin and Range seeing
potential blowing dust lowering visibilities. -078

&&

.FIRE WEATHER...

* Critical fire weather concerns are expected this weekend across W
  NV as series of potent cold fronts track through the area. Red
  Flag Warnings remain in effect for the Sierra Front eastward into
  the W NV Basin and Range Friday and Saturday.

* Elevated to isolated areas of critical fire weather conditions are
  expected late this afternoon in W NV as afternoon westerly gusts
  increase to 25-35 mph when afternoon RH drops into the upper
  single digits and lower teens.

* Friday will see more widespread gusty conditions as the first
  front moves through. West-southwesterly sustained winds of 20-25
  mph with gusts of 30-35 mph are expected across both the Eastern
  Sierra and W NV by mid-afternoon through early evening. RH
  continues to trend a bit higher in the latest forecast guidance
  with afternoon minimums now around ~15-25% across W NV. In
  addition, there will be a 15-25% chances of light showers with a
  10-15% chance for an isolated thunderstorm which may raise fire
  weather concerns.

* Critical fire weather conditions will lull Friday night into early
  Saturday as humidity recoveries increase to around 40-70%, but
  winds will remain breezy for mid-slopes and ridges.

* Saturday will see stronger wind potential as the main front sweeps
  through the region. Higher sustained winds of 20-30 mph with gusts
  of 30-40 mph are still expected with W NV afternoon RH dipping
  back down to ~10-20%.

* Overall, slightly higher RH values on Friday and Saturday may be
  negated by the stronger winds, dry fuels/grasses, and recent
  lightning holdover potential from last week`s storms.

* Eastern Sierra fire weather zones are also expected to see these
  same strong winds on both days with ridgetops seeing wind gusts
  near 80 mph. However, fuels have not been reported to be critical
  and minimum RH is expected to be around 30-40%. Fuentes/078

&&

.REV Watches/Warnings/Advisories...
NV...Red Flag Warning from 11 AM Friday to 11 PM PDT Saturday NVZ420.

     Lake Wind Advisory from 11 AM Friday to 11 PM PDT Saturday
     NVZ001>004.

     Lake Wind Advisory until 11 PM PDT this evening NVZ004.

     Red Flag Warning from 11 AM Friday to 11 PM PDT Saturday NVZ423-
     429.

CA...Lake Wind Advisory from 11 AM Friday to 11 PM PDT Saturday CAZ071-
     072.

&&

$$