Topaz, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

499
FXUS65 KREV 181916
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
1216 PM PDT Wed Sep 18 2024

.SYNOPSIS...

* Low pressure will bring scattered showers and thunderstorms
  this afternoon through Thursday, with snow in higher Sierra
  elevations.

* Well-below average temperatures continue through Thursday.

* A warming and drying trend starts on Friday with near to above
  average temperatures returning next week.

&&

.DISCUSSION...

The main weather event for the upcoming week arrives this
afternoon through Thursday, as an upper low moving southward along
the CA coast generates an area of deformation/upper divergence
across the eastern Sierra into parts of western NV. While isolated
cells are currently developing near the Sierra, the primary time
frame for best coverage will be from 2-8 PM. As for location of
the heaviest rainfall, the high resolution guidance favors areas
from Carson City southward to Douglas, Lyon, Alpine/far northern
Mono counties, and also north of Tahoe from I-80 to eastern Sierra
County. We`ll be keeping an eye on the Davis and Bear Fire burn
areas, where the risk of flooding or debris flow may be enhanced
if heavier rainfall rain rates occur.

Bands of showers and possible embedded thunder will linger into
the overnight hours across parts of far western NV and the eastern
Sierra, with the focus gradually shifting to areas near and south
of US-50 as the upper low continues its southward trek. Then for
Thursday, these similar areas south of US-50 will have the best
overall afternoon shower/thunder chances, with most cells moving
from east to west. For the duration of this event, the highest
probability of 1/2" or more total rainfall (35-70%) are favoring
eastern CA from eastern Sierra County southward across the Tahoe
basin to Alpine/northern Mono counties, and western NV in
Douglas/southern Lyon counties. This probability for at least 1/2"
of rain is not quite as high, but still a meaningful 20-40% for
the Reno-Carson area, the remainder of Lyon County and much of
Mineral County.

For higher Sierra elevations, the risk of accumulating snow
continues, mainly for Mono County where snow levels mainly
between 9000-10000 feet could impact the higher seasonal passes
(Sonora, Tioga) and the upper portion of CA-203 beyond the Mammoth
Mountain entrance. With the cold core of the upper low remaining
west of the Sierra, the snowfall amounts in the advisory area will
be more limited to heavier shower bands that linger tonight into
Thursday morning. Afternoon accumulations will be harder to come
by with the higher sun angles and precip likely to occur in short
bursts, as opposed to persistent larger scale snow areas. Also for
the Sierra ridges, a period of slightly enhanced NE-E winds
(gusts 30-40 mph) are anticipated from Thursday morning through
early Friday.

This weather system will depart with leftover showers diminishing
Thursday night, followed by a drier weather pattern from Friday
through the middle of next week. Temperatures will begin a slow
recovery starting Friday through the weekend (highs mid-70s to
near 80) with high pressure off the west coast keeping a light
north-northwest flow aloft. Then as the high shifts eastward into
the Great Basin next week, further warming is expected in lower
elevations with highs returning to the mid 80s by the middle of
next week, along with typical afternoon SW-W breezes. MJD

&&

.AVIATION...

Periods of SHRA/TSRA are expected through 04Z this evening, with
a 20-35% chance of lightning for all the main terminals, except
slightly lower (10-20%) at KRNO and KMMH. Mountain top
obscurations will occur, while the stronger cells could produce
brief periods of MVFR conditions in CIGS/VIS. Snow is less likely
to occur at KMMH (less than 10% for any accumulations) with snow
levels mainly near or above 9000 feet.

For Thursday, the best shower/thunder chances shift southward with
15-30% chance of lightning from KMEV/KTVL southward to KMMH,
dropping to 5-10% northward to KRNO/KTRK mainly between 19-04Z.
Again, the stronger cells will be capable of producing MVFR
conditions, with mountain top obscurations likely continuing into
Thursday evening.

With the exception of brief gusts up to 25 kt near t-storms,
light winds will prevail through the remainder of the week, with
VFR conditions prevailing from Friday onward, other than some
early morning fog around KTRK each day into the weekend. MJD

&&

.REV Watches/Warnings/Advisories...
NV...None.
CA...Winter Weather Advisory from 2 PM this afternoon to 8 PM PDT
     Thursday CAZ073.

&&

$$