146
FXUS65 KREV 241332
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
532 AM PST Sun Nov 24 2024

.UPDATE...

The Winter Storm Watch has been upgraded. Here are the following
updates for the upcoming winter storm early this week:

-A Winter Weather Advisory is in effect from 4 PM today until 4 AM
 Wednesday PST for Lassen-Eastern Plumas-Eastern Sierra Counties.

-A Winter Storm Warning is in effect from 7 AM Monday to 4 AM
 Wednesday PST for the Greater Lake Tahoe Area.

-A Winter Storm Warning is in effect from 4 AM Monday to 4 AM
 Wednesday PST for Mono County.

For more details on snowfall amounts and impacts, please visit
weather.gov/reno.

-Johnston

&&

.PREVIOUS DISCUSSION... /issued 235 AM PST Sun Nov 24 2024/

SYNOPSIS...

* Enjoy a short break in the active weather through early Monday
  morning with just a few lingering showers and afternoon breezes.

* Another storm brings more valley rain, mountain snow and gusty
  Sierra ridge winds Monday through Wednesday morning.

* For the Thanksgiving weekend expect generally dry conditions and
  cool temperatures.

DISCUSSION...

It is break time! Enjoy generally fair weather conditions today
into very early tomorrow morning. We are only expecting a few
brief rain and snow showers through the day as the environment
remains a bit unsettled, and some breezy and typical afternoon
winds. Winds remain a bit gusty over the Sierra crest ahead of the
next system, otherwise no significant impacts are expected.

Another wave approaches the area on Sunday evening. The first hint
of this will be winds increasing over the Sierra ridges tonight.
Winds continue to strengthen overnight resulting in gusty winds
again by Monday afternoon. Winds are not expected to be as strong
as this past weekend, but expect gusts in the 30-45 mph range in
the valleys with stronger winds over wind prone areas. Ridgetop
winds will keep blowing until at least Tuesday morning. Wind conditions
improve by Tuesday afternoon and/or evening.

The snow levels with this system will be fluctuating between 5-7
kft from Monday through Wednesday. HREF members show at least two
distinct bands of precipitation, one focusing over NE CA and the
other towards the Eastern Sierra. Therefore, it appears that
impacts start over Lassen and Plumas on Sunday night. Amounts will
be in the range of 5-8 inches above 7000 ft with isolated areas
up to 10-12" in the highest peaks. The second band will be
affecting the Tahoe Basin and the Eastern Sierra. The greatest
amounts will be expected over Mono county as ECMWF EFI indicates
an anomalous event in the southern side of the Sierra. Current,
forecast accumulations also show a signal for heavy snow in the
area. The Tahoe basin near the Sierra crest has a 10-30% of
observing 2 ft of snow, while near the crest in the Eastern Sierra
the chances shoot up to 60-90% above 8000 ft. Mono county could
still see impacts into Wednesday afternoon as the system leaves,
but there is still some uncertainty with the timing. Snow amounts
in the Sierra between 5000-7000 feet near the Tahoe basin will
range from 4-9 inches with a 20-60% chance of exceeding 6 inches.
Therefore, expect winter warning and advisories in the mountains
to highlight impacts.

For western NV, we are expecting mostly rain, as snow levels
remain too high. Anyway, between 0.2 to 0.5 inches of rain are
likely, especially the farther west we go. There are some low
chances for snow (around 20%) in the valleys towards the end of
the event on Wednesday. It is unlikely that we will see any snow
accumulations as the moisture leaves the region with the arrival
of the colder air on Wednesday morning.

Conditions improve on Wednesday afternoon as the system moves
east, and it is replaced by a northwesterly dry and cool flow.
Therefore, expect drier conditions with a few lingering showers,
especially south of Highway 50. Temperatures will be in a slow
warm up trend, but we should remain below normal for late
November.

-Crespo

AVIATION...

VFR conditions prevail through 12Z Monday, especially over western
NV. A few exceptions likely due to brief showers across the region.
KTRK, and similar areas will be developing FZFG in the early morning
hours between 09-15Z. We are also expecting mountain obscurations as
low clouds remain in the Sierra. Winds will be light and VRB during
the overnight hours, then become from the S and SW between 5-10 kts
and gusts up to 20 kts from 20Z to 01Z. Stronger winds expected
overnight at KMMH and vicinity. Turbulence and LLWS return after 03Z
tonight as FL100 winds start to increase with the approach of the
next system.

Conditions continue to deteriorate on Monday after 12Z with the
next system bringing valley rain and mountain snow above 5 kft.

-Crespo

&&

.REV Watches/Warnings/Advisories...
NV...     Winter Storm Warning from 7 AM Monday to 4 AM PST Wednesday
     NVZ002.

CA...Winter Weather Advisory from 4 PM this afternoon to 4 AM PST
     Wednesday CAZ071.

     Winter Storm Warning from 7 AM Monday to 4 AM PST Wednesday
     CAZ072.

     Winter Storm Warning from 4 AM Monday to 4 AM PST Wednesday
     CAZ073.

&&

$$