Little Valley, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

582
FXUS65 KREV 091045
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
245 AM PST Sat Nov 9 2024


.SYNOPSIS...

* Nighttime inversions will limit mixing and trap any smoke or
  haze in the valleys during the mornings.

* Gusty winds, mountain snow and valley rain arrive Monday with
  possible impacts to travel along the Sierra passes late Monday
  into Tuesday morning.

* Another system may be in the queue for late next week, which
  will keep us showery, cool and breezy.

&&

.DISCUSSION...

A quick glance this morning at fire.airnow.gov shows reduced air
quality close to areas where smoke from ongoing prescribed burning
has accumulated in Sierra valleys.  The overnight fair skies, light
winds, and radiation cooling will continue to aid in the
strengthening of inversions hold smoke particulates within their
margins. Although high pressure is projected to weaken through the
weekend, these inversions will continue to exert influence upon
visibility and air quality in those areas affected which includes
the Truckee Meadows. Hi-Res guidance shows a weak, fragmented
upper short wave trough passing quickly overhead the region
overnight into Sunday morning. This may allow for adequate mixing
into Sierra and far western valleys that clear-out most of this
unwanted smokey air.

A second, stronger storm system will advance into northern CA
overnight Sunday into Monday, and bring a period of gusty
southwest winds, mountain snowfall, and valley rain into western
NV mostly north of Hwy-50.

* Although ensemble multi-run projections show a slight downward
  trend for precipitation amounts, the Sierra will still receive
  at least up to 0.5-0.6 inches of liquid across higher elevation
  areas. This equates close to 6 inches of storm total snowfall
  above 7000 at a liquid to snow ratio of 10:1-12:1 starting
  early morning Monday through Monday evening. This may bring
  about a messy impact to any commute over higher Sierra passes,
  especially going into the evening hours Monday. Blended guidance
  gives an early 40-50% chance for 4+ inches of snowfall across
  Donner pass, as an example for higher Sierra passes. The same
  guidance also projects a 10-20% for up to 8.0 inches of snow
  over the same location. But, this may be a better projection
  for higher ridgetops west of the Lake Tahoe Basin. Speaking of
  the Lake Tahoe Basin, blended guidance gives a 20-30% chance for
  at least an inch at lake level. Much of the liquid rainfall
  amounts will be shadowed eastward into western NV. Showers that
  do make it into western NV through Monday will still deposit a
  few hundredths of an inch of rain, mostly north of Hwy-50.

* Snow isnt the only impactful element with this storm. Gusty
  southwest winds will peak at 70-90 mph across higher Sierra
  ridges. These gusty southwest winds will eventually mix down
  into western NV valleys with wind gusts to 35-45 mph later
  Monday morning through the afternoon. The more wind prone areas,
  such as the US-395 corridors across Lassen County, and Douglas
  County into Mono County, could see gusts to 50 mph. Areas along
  I-580 across the Washoe Valley on Monday may see gusts to 50-55
  mph as well.

Taking a more careful look through the rest of next week, close
alignment of both ECMWF and GEFS simulations heighten confidence
in timing and precipitation projections. Therefore, projections
for the relative strength of storms forming within this late week
period of active weather may yield a higher volume of moisture to
the Sierra and western Nevada. Cluster ensemble guidance points
toward better chances for a long wave trough pattern injecting
periodic waves of energy and moisture into the western US late
next week. But its guidance also shows a higher risk for inside
sliders dropping south- southeast along the Sierra into the
central Great Basin after next weekend. So on the flip side, this
period may see a better chance for colder temperatures spreading
further east into the Great Basin, and south as well.

This combination of factors could project an increased chance for
higher snowfall amounts across the length of the Sierra as well.
This should put a smile on those winter enthusiasts waiting
anxiously for more snow in the high country. But, this forecast
comes with those nuances inherent with long range forecasts --
constant adjustments. More to come, please stay tuned to this
channel. -Amanda

&&

.AVIATION...

* Persistent high pressure with fair skies, dry conditions, and
  light winds will continue to provide for VFR conditions at area
  terminals. Local prescribed burning and overnight inversions
  will also increase the chance of CIG/VIS reductions due to
  smoke/haze trapped in valley areas, particularly for KRNO and
  KTRK. Slantwise visibility may be impacted.

* Passing shortwave troughs will bring mid to high level clouds
  today through Sunday. Also, look for FL100 winds to increase to 15-
  25kts from the southwest today after 15Z that continues to 15Z
  Sunday.  FL100 winds will further increase to 40-45kts late Sunday
  into Monday as a stronger, colder system approaches the Sierra and
  western Nevada. By Monday, an attendant cold front will bring
  periods of gusty surface winds, mountain snow, and valley rain
  that persists overnight Monday night. -Amanda

&&

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

$$