Mammoth Lakes, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

362
FXUS65 KREV 140924
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
224 AM PDT Mon Apr 14 2025

.KEY MESSAGES...

* Warmer weather through Wednesday with increased snowmelt resulting
  in streamflows running fast and cold.

* Afternoon showers and thunderstorms are possible through midweek
  with isolated flash flooding potential in the Sierra on Wednesday.

* A cold front may bring light mountain snow, more thunderstorms,
  gusty winds, and cooler weather Thursday and Friday before a
  warming and drying trend prevails Easter weekend.

&&

.DISCUSSION...

Noticeably warmer weather is in store for the first half of this
week with daytime highs in the 60s and 70s for Sierra and western
Nevada communities, respectively. It`s likely that we`ll be several
degrees shy of record breaking warmth, but the warmer weather will
increase snowmelt and lend to very cold, fast-flowing creeks and
streams. No flooding impacts from snowmelt are anticipated, but it`s
a good reminder to start preparing as we`re nearing the time of the
year when snowmelt flooding becomes a greater concern.

A multi-day period of afternoon showers and thunderstorms begins
today and lasts through midweek as our warmer weather overlaps with
large scale ascent and increased moisture. The prospect of showers
and storms is lowest this afternoon (~10 chance) as we`ll remain
decoupled from the greater moisture aloft until Tuesday. However,
a lifting deformation zone may provide just enough forcing for
ascent to initiate a few showers and/or a stray thunderstorm this
afternoon in the Sierra from the Tahoe Basin southward.

An upper cyclone will deepen off the southern California coast
Tuesday into Wednesday, drawing moisture aloft northward into the
region and positioning us in a favorable location for large scale
ascent beneath the left exit region of an upper jet. In response,
chances of thunderstorms increase Tuesday and Wednesday afternoon to
10-20% and 15-30%, respectively, and spatially favors the Sierra
around and south of the Tahoe Basin and higher terrain south of the
I-80 corridor. However, showers and storms may drift into adjacent
foothill and valley locales (including the Greater Reno-Carson City-
Minden area) each afternoon. With that being said, increased upper
cloudiness may serve as a limiting factor and decreases confidence
in the extent of thunderstorm coverage Tuesday and Wednesday. Any
thunderstorms that do develop are expected to remain sub-severe
given a lack of deep-layer shear, but the strongest storms will be
capable of brief downpours, strong outflows, and occasional
lightning. Storm motions will be rather slow owing to weak
steering flow in the cloud-bearing layer, which may pose an
isolated flash flooding risk in the Sierra on Wednesday when storm
potential is greatest.

After a few days of spring-like weather, it appears that we`ll
briefly revert back to winter late this week as a slider-type trough
and attendant cold front moves through the region. Light mountain
snow and lower snow levels, gusty north winds, much cooler
temperatures and lower snow levels, and even a chance of
thunderstorms/pellet showers are among possible outcomes on Thursday
and Friday, but there is still some uncertainty in details that will
need to be sorted out. A warming and drying trend will likely make
for a mild Easter weekend.

-Salas

&&

.AVIATION...

VFR conditions and light afternoon breezes expected today areawide
with cumulus build-ups in the Sierra south of Tahoe. Showers and
perhaps a stray thunderstorm or two appear possible this afternoon
between KTVL and KMMH, although odds of lightning within 10 miles
of KTVL and KMMH are only 10% or less from 20Z to 02Z. Impacts
from showers and thunderstorms are most likely on Tuesday and
Wednesday afternoon, especially at Sierra terminals.

-Salas

&&

.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&

$$