Area Forecast Discussion
National Weather Service Reno NV
249 AM PST Tue Jan 10 2023
.SYNOPSIS…
Another storm moving into the region this morning will bring heavy
Sierra snow into Wednesday and snow to valley floors through early
afternoon across western Nevada. We`ll see a break in storm activity
late Wednesday through Friday, before more storms affect our region
this weekend and next week.
&&
.DISCUSSION…
NEXT STORM (TODAY – WEDNESDAY AM):
* CURRENT CONDITIONS: As of this writing, the last in a series of
extratropical cyclones (at least for the work week) is making
landfall over the central-northern California coast. Infrared
satellite imagery shows a well-defined baroclinic leaf with a warm
front entering the western Sierra Nevada. A vigorous arc of
convection ahead of a potent mid/upper-level shortwave trough will
move into the Sierra Nevada this morning, leading to heavy
snowfall and snowfall down to valley floors.
* SNOW TO VALLEY FLOORS THIS MORNING: Across far western Nevada,
skies have cleared, leading temperatures to drop 5 to 10 degrees
from the upper 30s to low 30s area-wide. This forming cold dome
has primed the boundary layer for snowfall this morning. A
strong cold front with significant frontogenesis owing to
intense diabatic warming within the convective complex ahead in
the warm sector, and vigorous cold air advection directly behind
the front, will cross the Sierra Nevada into western Nevada this
morning between 4:00 to 7:00 AM PST. The strong cold front and
convection will generate a band of moderate-to-heavy snowfall,
which will affect western Nevada through noon. A quick 2 to 4″
of snowfall is possible down to valley floors, with 3 to 7″
above 5000 feet in far western Nevada. Relatively warmer air
(upper 30s) within the Basin and Range will help to keep snow
levels above valley floors (approximately 4500 feet), leading to
a mix of rain and snow. Trace to 3″ of snowfall is possible
above 4500 feet over Pershing and Churchill counties through
2:00 PM PST. Residual isolated light snow showers will be
possible in the afternoon across western Nevada but will not
generate much, if any impacts. However, the commute this
morning will likely have plenty of travel impacts. So, leave
early and allow time to reach your destination.
* HEAVY SIERRA SNOW (THROUGH WEDNESDAY AM): The warm front
associated with the aforementioned extratropical cyclone is
currently moving into the Sierra Nevada, which will be followed
by the vigorous cold front and convection. Heavy snowfall will
resume through the evening, with moist upslope flow keeping snow
going for the warning areas of northeast California and the
Sierra into tonight. Snow showers will finally wind down early
Wednesday morning across the Sierra. An additional 18 to 36″ of
snowfall is possible in the Sierra above 7000 feet, with about
10 to 20″ likely for the Lake Tahoe Basin. Further south into
Mono County, additional snow accumulations of 4 to 10″ are
possible along US 395, with 1 to 3` of snow above 7500 feet and
localized amounts up to 4 feet at the Sierra crest. Some
isolated lightning is not out of the question in the Sierra and
even western Nevada through the day.
* WINDS: Strong wind gusts 80 to 100 mph will be possible across the
Sierra crest today. Some stronger winds could mix down into the
Sierra valleys (to 45 mph) and across far western Nevada (to 35
mph) during breaks in precipitation. Wind prone areas across
southern Lyon-Mineral counties could see 50+ mph gusts into the
afternoon.
A BREAK (FINALLY) WEDNESDAY THROUGH FRIDAY:
* A quick weather system will bring chances for light snow to the
Sierra and northeast California Wednesday before a weak ridge
builds into the region Thursday and Friday, with mainly dry and
quiescent conditions expected. Most of the light snow showers in
the Sierra and northeast California Wednesday will be focused
along and north of Interstate 80, with some road impacts expected.
* Well, why not keep the storm train going? Ensemble guidance shows
a couple of weather systems impacting the Sierra and western
Nevada this weekend. Snow looks to mainly impact the Sierra
Saturday and Sunday, with western Nevada seeing light rain. There
is the potential for another round of Sierra snow and possibly
valley snow Sunday into Monday, with wind impacts to aviation and
recreation.
