Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 292223
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
323 PM PDT Wed Mar 29 2017

.SYNOPSIS...

Dry conditions, light winds and warm temperatures stick around
for one last day before a storm pushes into the region late
tonight into Thursday. The storm on Thursday will bring a strong
cold front through western Nevada with gusty winds as well as
rain, snow, and pellet showers. Cooler temperatures will stick
around through the end of the week behind this cold front.

&&

.SHORT TERM...

Latest visible satellite imagery shows cloud cover increasing
across northern California and northwest Nevada ahead of next
spring storm which will arrive earlier Thursday morning. This
storm will provide a strong and fast moving cold front which will
races through the region early tomorrow morning.

This front will be accompanied by a strong surface pressure
gradient which will result in stout sustained winds and valley
gusts in the 40 to 50 mph range. The strongest winds in the area
are expected through Mineral and southern Mono counties where the
gradient and terrain orientation will be favorable to produce
sustained wind as high as 30 to 40 mph with gusts exceeding 60
mph. High Wind Warnings are in place for Mono-Mineral with Wind
Advisories covering most other areas across the Tahoe Basin and
northwestern Nevada.

Forecast simulations continue to quickly push the cold front near
the I-80 corridor around 6-8am. This front is also rather dynamic
and will provide the best chances for precipitation as it moves
through. There is enough instability and frontogenetical forcing
to yield convective banded precipitation along the front which
could even yield isolated thunderstorms in the morning. Snow level
will lower to around 6,000-6,500` behind the front but could
temporarily drop to near 5,000` right as the front passes. As
such will see a mix of rain and snow showers for valleys with
accumulating snow pellet (graupel) showers possible with the
front. A few inches of snowfall will be possible through the
Sierra but should be a rather quick hit for precipitation with not
much accumulation expected along roadways.

Showers will shift into central Nevada and diminish Thursday
evening into Friday morning. Surface winds will shift out of the
north to northeast and remain breezy Friday. Winds across ridgetop
will also become strong and gusty but will come out of the more
uncommon easterly direction. Winds lighten for Saturday and highs
will rebound back into the mid and upper 60s across western Nevada
with mid and upper 50s for Sierra valleys. Fuentes

.Long Term...Sunday through Wednesday...

On Sunday another fast cold front is expected to be brushing through
NE California and into Nevada. Models have keyed in better with the
timing but continue to struggle with how much they want to dig this
shortwave in as it passes through the area. Currently it is enough
to cause an increase in winds, cloud cover, and bring about a chance
of light precipitation.

Monday and Tuesday will be a return to northwest flow with weak
shortwave building in for at least Monday. Tuesday another shortwave
could move through the flow, but at this time, it is only strong
enough to bring about a slight increase in winds and clouds. A large
scale trough developing in the eastern Pacific begins to increase
the chances for precipitation for the second half of next week. For
more on this check out the new Week 2 Outlook below. -Zach


.Week 2 Outlook...Issued 3pm 3/29

The last few weeks the west coast has been in a fairly typical
spring weather pattern. The Pacific jet stream was retracted to the
west allowing weak fast moving low pressure systems to drop out of
the far eastern Gulf of Alaska with limited moisture potential.

This is expected to change next week as the jet strengthens and
moves into the eastern Pacific. Ensemble models are in good
agreement that a large area of low pressure will deepen along the
west coast. Atmospheric river (AR) detection tools show a strong
signal for an AR to impact the west coast in the 7-10 day time
period.

At this point, it is likely that an AR will reach the west coast by
the end of next week with the current forecasts favoring the
Pacific Northwest; however, intensity and especially latitude are
still in the realm of low predictability. The deepening low
pressure and strengthening jet in the eastern Pacific, along with
strong AR signals for the west coast during the second half of
next week increase the chances for a return of stronger storms
impacting the Sierra and western Nevada. The main question is how
far south will the moisture and jet stream drop next week.
Increased chances are not a guarantee, but definitely worth
keeping an eye on as a direct hit from another AR would again
increase flooding concerns in the region. -Zach

* The Week 2 Outlook discussion is an experimental part of the Area
  Forecast Discussion. This product is designed to highlight the
  potential for significant pattern changes beyond day 7 and will
  not be issued on a daily basis.

&&

.AVIATION...

A strong fast moving cold front will move through the region late
tonight through early afternoon Thursday. Winds will increase this
afternoon and overnight ahead of the front. Along the front, a few
hours of rain/snow pellet showers will be possible, especially for
KTRK/KTVL where reduced VIS/CIGS and mountain obscurations will be
likely. Isolated thunderstorms will also be possible for a few hours
for all terminals as the front moves through. Strong winds at all
terminals are likely with low level wind shear also possible
along the leading edge of the front.

Current estimate for timing at KTRK/KTVL/KRNO/KCXP is this: Best
chance for wind shear and possible light showers 9-12Z. Possible wind
shear with increasing chances of rain/snow and thunderstorms 12-17Z.
For KMMH the timing will be about 4-6 hours later with stronger
winds likely for Mono County. -Zach

&&


.REV Watches/Warnings/Advisories...
NV...Wind Advisory from 5 AM to 11 PM PDT Thursday NVZ004-005.

     High Wind Warning from 8 AM to 8 PM PDT Thursday NVZ001.

     Wind Advisory from 5 AM to 8 PM PDT Thursday NVZ002.

     Wind Advisory from 5 AM to 8 PM PDT Thursday NVZ003.

CA...Wind Advisory from 5 AM to 11 PM PDT Thursday CAZ070.

     High Wind Warning from 8 AM to 8 PM PDT Thursday CAZ073.

     Wind Advisory from 5 AM to 8 PM PDT Thursday CAZ072.

&&

$$

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


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