Calpine, California Weather Forecast Discussion

663
FXUS65 KREV 150817
AFDREV
Area Forecast Discussion
National Weather Service Reno NV
117 AM PDT Mon Sep 15 2025
.KEY MESSAGES...
* Warmer temperatures and mostly dry conditions are expected
  through mid-week, then some cooling returns by late week and the
  upcoming weekend.
* Showers and isolated thunderstorms may return as soon as
  Thursday near the Sierra, with increasing chances Friday and
  Saturday.
&&
.DISCUSSION...
An upper level ridge slowly moves east from the CA coast into the
Great Basin from today through Wednesday, leading to dry
conditions, mainly light winds and temperatures warming to above
mid-September averages. Afternoon highs rise to the mid-upper 80s
for lower elevations and around 80 degrees for Sierra communities,
with Wednesday appearing to be the overall warmest day, although
not much of a temperature drop is projected for Thursday.
An area of low pressure offshore from southern CA then approaches
the coast, pulling in some increased moisture with PWs increasing
into the 0.6-0.8 inch range. This moisture push is projected to
reach the eastern Sierra by Thursday afternoon, then spread
northward by Friday and Saturday. Due to varying tracks of this
low among the medium range guidance, confidence is lower on
rainfall amounts and coverage. While rain chances increase to
20-50% from Thursday-Saturday, thunderstorm chances are on the
lower side (10-15%) as some scenarios may not produce favorable
forcing with this system. Increased cloud cover may also limit
instability as temperatures start to trend downward from late
week into the upcoming weekend (70s near the Sierra to lower 80s
in western NV valleys).
For late weekend into early next week, precip chances start to
decline, but will be highly dependent on the eventual track of the
upper low. Scenarios varying from a slow passage across
central/southern CA (cooler with shower chances lingering) to a
quicker exit with high pressure ridge rebuilding into parts of
CA/NV (warmer/drier). MJD
&&
.AVIATION...
VFR conditions and light winds prevail through midweek at the main
terminals. Only exception is at KTRK, where patchy fog could
bring LIFR conditions at times this morning and Tuesday morning
mainly between 10-15Z. Also near KMMH, smoke aloft from the
Garnet Fire may bring hazy conditions and minor reductions in
slantwise visibility this afternoon and evening. MJD
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$

NWS REV Office Area Forecast Discussion