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Area forecast discussion
National Weather Service Reno Nevada
121 am PDT sun Sep 23 2018


The Sierra and western Nevada will remain dry through the week
with warm afternoons and chilly mornings. Breezy afternoons are
forecast again today, followed by several days of lighter winds.
By the first week of October, cooler and wetter weather may be in
store for the Sierra and western Nevada.


trough pushes through the region today bringing enhanced afternoon
winds along with a slight cooldown across the Sierra and western
Nevada. Wind gusts should remain below 30 mph for the most part, but
some localized wind gusts up to 35 mph will be possible. See the
fire weather discussion for fire concerns. Temperatures will cool
behind the frontal passage, but no precipitation is expected with
the dry trough.

Main impact from the trough will be the cooler temperatures by
Monday along with cold air advection induced east winds across the
higher terrain Monday night into Tuesday. The colder air will allow
the east-west gradient to tighten across the Sierra and produce wind
gusts along the ridges between 35 to 45 mph Monday night.
Temperatures will begin to warm up again by midweek as a ridge
develops across the region. Highs will warm into the high 80s to
near 90 for western Nevada valleys with upper 70s to mid 80s in
the Sierra valleys.

By late this week model solutions begin to diverge leading to a
lower confidence forecast. Although the cutoff low in the eastern
Pacific appears to move eastward towards the West Coast by late
week, there are some timing differences to contend with. Both the
GFS and the European model (ecmwf) show the cutoff low making its way across the
region sometime next weekend and into the next week. Either way
the pattern is looking cooler and also trending towards a better
potential for rain by the first week in October. -Edan



Core of strongest winds aloft (250 mb winds 80+ kts) extended
across the Tahoe basin and northern Nevada early this morning. These
winds are forecast to gradually diminish through the day as the
upper level trough swings eastward into the central-northern
rockies. So strongest ridge winds are occurring early this morning
with gusts around 40-45 kts. These winds will gradually subside
during the day before dropping off quickly this evening as
gradients relax. Lee side turbulence will continue today with the
worst conditions this morning and early afternoon. Another round
of gusty surface winds will develop by late morning in the Tahoe
basin and down at lower elevations this afternoon (gusts 20-25
kts). Low level wind shear is possible as these gusty winds move down into the
valleys this morning and early afternoon. Hohmann


Fire weather...

We will continue to headline the dry and breezy conditions today.
While critical fire weather conditions are expected to remain
isolated with short duration, fire weather concerns will be elevated
and any new fire starts could still spread quickly during the peak
wind period from mid-afternoon to early evening.

Areas most likely to see short periods of wind gusts 30-35 mph
combined with minimum relative humidity between 8-16% will be along the Sierra
front and parts of west central Nevada (fire zones 450 and 453). The
strongest upper level and Ridgetop winds are still expected this
morning followed by decreasing winds through the day as the trough
swings southeast. This would most likely result in a shorter period
of wind gusts exceeding 30 mph for lower elevations, although these
winds will likely mix down earlier in the afternoon compared to
Saturday. Some cooling and presence of cloud cover today may also
limit the duration of the lowest humidity during the day, especially
for portions of the Sierra front and areas north of I-80. Mjd


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