Mammoth Lakes, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

351
FXUS65 KREV 190924
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
224 AM PDT Thu Sep 19 2024

.SYNOPSIS...

* A low pressure system will bring scattered showers and
  thunderstorms today mainly south of I-80, with snow in higher
  Sierra elevations.

* Well-below average temperatures continue today, followed by
  near-average temperatures Friday through the weekend.

* Quiet fall-like weather is expected starting Friday, with sunny
  skies and light winds persisting into early next week.

&&

.DISCUSSION...

The center of the low pressure system is making its way down the
coast and headed for SoCal tonight. As it brushes by northern
Nevada, we`re seeing an area of frontogenesis/deformation set up
south of I-80. Rain showers are currently ongoing at the time of
this writing from Storey County down to Mono County, but are
expected to fizzle out by daybreak. Very low chances of around 10%
for lightning are expected out of these showers as well. Through
this morning we`ll have a few showers (20-30%) that linger over Mono
and Mineral counties.

As we get into this afternoon, hi-res models have another round of
scattered thunderstorms mostly south of I-80, although a few showers
may pop up around Pyramid Lake. Current chances are 20-50% across
western Nevada and 70-80% from Lake Tahoe south along the Sierra.
With these afternoon showers, we`ll likely see some degree of
lightning activity, as current chances are 20-30%. Snow will be back
in the forecast today, but only a dusting up to 2" above 9500`.
Tioga Pass will likely see some snowflakes falling again, but only
half of an inch is expected in the morning before the snow switches
over to rain around 10am-12pm. With that low moving further south
throughout this afternoon and instability diminishing after sunset,
we can expect all showers to be done by 11pm tonight.

After today, the weather really quiets down. Temperatures start to
level off around 80 in lower valleys and 70`s in the Sierra. Winds
will be relatively light each afternoon through the weekend and into
early next week. There`s what looks to be a possible Rex Block
setting up just off the West Coast the first half of next week.
High pressure will be working in our favor at first, then as the
Block breaks down, a shortwave trough brushes by northern Nevada
on Wednesday. Not a huge concern as of right now other than the
potential for gusty winds, but something we`ll monitor as we get
closer to Wednesday.

-Justin

&&

.AVIATION...

Ongoing dense fog at KTRK that will likely disperse between 13-15Z
this morning. There are also some rain showers over KRNO/KCXP/KMEV
that will pass by 11-12Z this morning. Expect just a few more
hundredths of an inch of precip this morning from these showers.

A 30-50% chance of showers and a 20-30% chance of lightning are
expected this afternoon from KRNO down to KHTH, including KTRK and
KTVL. KMMH will have a greater chance of seeing thunderstorms at
70%. The best timing of the showers will be from 20Z-05Z. FL100
and sfc winds will be relatively light throughout today, although
we can`t rule out some light turbulence.

With the exception of brief gusts up to 25 kt near t-storms, light
winds will prevail through the remainder of the week. VFR
conditions will prevail from Friday onward as well, with the
exception of fog returning to KTRK tomorrow morning.

-Justin

&&

.REV Watches/Warnings/Advisories...
NV...None.
CA...Winter Weather Advisory until 8 PM PDT this evening CAZ073.

&&

$$