Scientific Forecaster Discussion
fxus65 krev 151109
Area forecast discussion
National Weather Service Reno Nevada
309 am PST sun Dec 15 2019
High pressure builds overhead early this week for quieter weather.
Developing inversions will bring limited ventilation for valleys
Monday and Tuesday. A weak storm is expected Wednesday for a chance
of light snow, mainly in eastern California. Below average
temperatures will rebound to around average mid to late week. A
stronger storm could impact Holiday travel next weekend.
An upper disturbance which brought an earlier burst of light to
moderate snow is moving off into central and eastern Nevada. In
its wake, many roads are slick or lightly snow-covered in eastern
California, western Nevada (except on valley floors in the Reno-
Sparks area), and along Interstate 80 north of Lovelock. As only
minimal additional showers are expected at best, roads should
clear up this morning; however, check with caltrans and/or ndot
for the latest travel restrictions if venturing out this morning.
The next few days will be on the tranquil side as high pressure
builds into northeast California and western Nevada. Inversions
will strengthen starting on Monday as subsidence warming aloft
ensues under the building ridge. This will lead to limited mixing
and ventilation of valley air Monday and Tuesday with some pollutants
possibly building up to moderate levels. Temperatures will remain
below average through Tuesday, with nighttime lows moderating
substantially by Tuesday night as cloud cover increases ahead of a
weak mid-week system. -Snyder
Long term...Wednesday through next weekend...
A weak storm system will move into the Sierra on Wednesday, bringing
a chance of snow to the Sierra along with gusty winds. This system
will be falling apart as it moves inland so not expecting any major
impacts from this storm other than some light accumulations over
the passes Wednesday and Wednesday night.
Ridging increases over the Great Basin Thursday and Friday with the
storm track shifting further north into the Pacific northwest. By
Saturday night and Sunday, a trough will finally swing into California/Nevada
bringing precip into our region. Latest trends continue to lessen
the precipitation for our region as the trough looks to dive south
and bring more of a southerly flow over the Sierra which would
limit the orographic lift and spillover.
Winter storm conditions will be possible in the Sierra during this
time, especially Sunday as the trough swings inland. Ensembles are
still struggling with how much precip we will see on the east side
of the Sierra and into western Nevada, but it does look like the
main impacts of this storm will be mostly in the High Sierra with
snow and less impacts for western Nevada. That being said, we are
still a week out and things could change. Anyone with travel plans
before the Christmas Holiday should continue to monitor the weather
for potential winter weather impacts. -Hoon
Isolated light snow showers remain possible through the early morning
hours, although little to no additional accumulations are expected.
Ceilings will improve through the morning with VFR conditions for all
terminals for today. Could see some IFR freezing fog tonight at
ktrk, mainly after 03z and into Monday morning. -Hoon