Glenbrook, Nevada

... Gulf of Alaska storm should reach the area Wednesday...

A cold area of low pressure in the Gulf of Alaska is forecast to
drop south toward the Sierra and western Nevada later this week.
This storm will bring a cold front with a period of moderate to
heavy precipitation into the area between Wednesday afternoon and
Thursday.

Ahead of the front Wednesday afternoon and Wednesday night... windy
conditions are possible along and south of Interstate 80. Gusts of
40 to 45 mph may occur along Highway 395 from Reno south to
Mammoth Lakes. Sierra ridge gusts could reach 100 mph as the cold
front approaches.

Along the front rain and snow should move into northeast California
and northwest Nevada Wednesday afternoon and reach the Reno-Tahoe
area Wednesday evening. Several inches of snow are possible in the
Sierra as snow levels drop below 6000 feet Wednesday night.

Once the front passes Thursday snow levels could drop to the
western Nevada Valley floors as cold air moves into the area.
There is potential for a second burst of precipitation moving into
the area Thursday... which could bring snow accumulations to the
western Nevada Valley floors.

Check our website at weather.Gov/Reno or listen to NOAA Weather
Radio for updates on this developing storm.

.Long term... Friday through Monday...
uncertainty continues for the medium range period... especially
Friday and Saturday when another shortwave may affect the region.
The latest ECMWF came in colder and wetter than its previous run and
the current GFS/Canadian/ensemble guidance data. Based on the
trajectory of this system... qpf values on the ECMWF appear to be too
high for the Sierra. The ECMWF has often been a trend setter when
dealing with changing conditions... but even this model also has been
jumpy from run to run during the past few days. Since all of the
medium range guidance has been struggling with weather features in
the ern Pacific... .confidence in the track and timing of any system
affecting ern CA-wrn NV is below average.

Due to the shaky confidence... pops will be capped as slgt chc for
the current forecast... starting late Fri in nern CA-far nwrn NV and
extend to most zones Fri ngt and into Saturday. One element of the
forecast which appears more likely is for below normal temps to
continue for Fri-Sat due to the multiple shortwave passages
occurring starting with the Wed-thurs system. Even if this system
for Fri ngt-Sat does not produce much precip... snow levels should be
down to near most valleys with Max temps unlikely to reach 50
degrees either day. The ECMWF scenario would lead to even cooler
temps... which would extend thru the remainder of the weekend.

For Sunday-Monday... more consensus appears for ridge rebuilding near
the West Coast with the axis then progressing east into the Great
Basin. Weak sfc flow and low sun angles will produce inversion
conditions that will limit rises in temps for the lower
elevations... with Max temps only in the lower-mid 50s by Monday.
Mjd


.Aviation...
VFR conds with wdsprd mid-high cloud coverage thru Tuesday. Cigs
should remain near or above 10000 ft agl during periods of thickest
cloud cover btwn 06z-18z. Ridge gusts in the Sierra 40-50 kt thru
12z tues... but sfc wind gusts at area taf sites expected to remain
20 kt or less. Mjd