Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 211041
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
241 AM PST Tue Nov 21 2017

.SYNOPSIS...

Drier conditions will prevail through Wednesday night as high
pressure builds overhead, with light rain possibly returning on
Thanksgiving Day for northeast California and far northwestern
Nevada. Impacts should be minimal with very high snow levels.
Temperatures will remain well above average into next weekend. A
colder storm system is possible early next week.

&&

.SHORT TERM...

A mild and very moist (relatively anyway) airmass has settled into
northeast CA and western NV behind the recent warm air advection.
In fact, based on SPC climatology from the past 30 years or so,
the evening sounding yesterday from Reno indicated a precipitable
water that was higher than any other reading between late October
and early May, excepting a small period in early January. While
this is a curious statistic, it doesn`t mean much impact-wise
as there is little to no forcing to squeeze out the high
atmospheric moisture content.

High pressure will strengthen over northeast CA and western NV
through Wednesday, directing the storm track into the Pacific
Northwest and keeping a very mild airmass over the region through
Thanksgiving Day (and beyond). In fact, a few sites may even
threaten record highs Wednesday and Thanksgiving Day, including
the Reno airport where the record high is 69 both days.

Thursday/Thanksgiving Day, the upper ridge will flatten a bit as
energy moves into the Pacific Northwest. This is simulated to
bring a brief, weak period of moisture transport into northeast
California and northwestern Nevada. With the energy so far to the
north, the moisture feed should dissipate as it drops into the
northern Sierra and western Nevada so precipitation amounts are
expected to remain very modest. The airmass will remain quite mild
with snow levels 9,000 to 10,000 feet over northeast CA so little
or no impact is expected. -Snyder

.LONG TERM...Friday through Monday...
The overall ideas remain the same this morning with ridging giving
way to a colder trough for late Sunday into Monday. The main changes
with this forecast were to lower snow levels associated with the
trough and also to increase the chance of rain/snow Sunday night.

EC/GFS continue to show the ridging gradually weakening, but
remaining strong enough Friday to keep it dry and mild. It will
remain mild into Saturday as winds aloft begin to increase for
better mixing, along with a small threat of showers north of I-80.

For the trough late Sunday into Monday, the winds look gusty with
700 mb winds between 50-60 kts. It would be quite windy in this
scenario. As far as precip, it does not look to be a big precip
producer as it will be weakening and lifting north as it moves
through. It will be colder though, with snow levels averaging
6500-7000 feet which could impact the passes. Behind the main
cold front, snow levels will drop to 5000 feet or lower. However,
by that time almost all the precip will have ended.

&&

.AVIATION...
VFR through Wednesday, but FG will be an issue around KTRK through
17Z this morning. It will likely form again tonight as the ground
remains moist and skies will be mostly clear aside from some high
clouds. Winds look to be relatively light the next 36 hours. The
next storm to have an impact does not look to hit until late in the
weekend.

&&

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

$$

For more information from the National Weather Service visit...
http://weather.gov/reno


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