Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 130409 AAA
AFDREV

Area Forecast Discussion...UPDATED
National Weather Service Reno NV
909 PM PDT Tue Sep 12 2017

.UPDATE...

Storms this afternoon/evening were not overly strong with most
wind gusts around 40 mph or less, small hail and brief torrential
rains. There were a few measured amounts close to a half inch.
They did produce copious amounts of lightning and even at the 9
o`clock hour were still producing a fair amount across the Basin
and Range associated with a complex of storms there. Latest
radar/satellite imagery show storms are on the decrease. Isolated
storms will still be possible overnight as an upper low near the
central CA coast keeps the Sierra and western NV in a favorable
spot for large scale lift. This low will begin to move inland
Wednesday with another day for scattered showers and storms.
Hohmann

&&

.PREVIOUS DISCUSSION... /Issued 112 PM PDT Tue Sep 12 2017/

SYNOPSIS...

Low pressure near the California coast along with above normal
moisture will produce good chances for showers and thunderstorms
through Wednesday. The first cold front of the Fall season will
bring gusty winds Thursday along with another chance for showers
or storms. The cold front will bring much cooler temperatures
Thursday and Friday, with a modest warm up for the weekend.

SHORT TERM...

Current satellite imagery shows scattered showers and thunderstorms
are developing and moving from south to north. For this afternoon
and again tomorrow afternoon the ingredients are in place for
scattered thunderstorms and localized heavy rain. Computer-modeled
vertical profiles of the atmosphere show long skinny CAPE and not
a lot of shear both afternoons, which suggests small hail and
wetting rains are likely. There is also potential for some
stronger/severe thunderstorms. Latest runs of high resolution HRRR
model is consistent with this, showing areas of showers along
with pockets of stronger cells. Any stronger cells that do develop
will have potential for flash flooding (especially in steep
terrain or on burn scars), gusty outflow winds 40 to 50 mph, and
possibly up to 3/4 inch size hail.

For tonight and again tomorrow night, areas of rain are likely to
persist overnight, with isolated embedded thunderstorms possible.

For Thursday, a cold front will bring westerly winds with peak
gusts 25-35 mph in valleys and 35-50 mph along ridges. The relative
humidity/wind gust combination doesn`t look too critical, although
a few hours of red flag conditions in Mineral County may be possible
Thursday afternoon. Showers (especially north of I-80) and a slight
chance for thunderstorms (mainly east of highway 95) are also possible
with the frontal passage Thursday. JCM

LONG TERM...Friday into next week...

Computer guidance continues to show troughiness for Friday into
next week. If skies are clear overnight there is potential for
frost in colder valleys, so gardeners should check their forecast
overnight temperatures and be prepared. Light northerly flow
Friday/Friday night will shift to a dry southerly flow Saturday as
the next trough approaches. This should lead to a slight warming
trend for afternoon temperatures Saturday and Sunday, with highs
forecast to be 75-85 in western NV and 65-75 for most Sierra
communities. A cold front passage could bring strong gusty winds
Sunday night/Monday along with much cooler temperatures early next
week (highs could be mainly in the 60s Tuesday). The trough could
also bring a chance of showers to the Sierra and northern CA by
Monday afternoon, possibly spreading south and east across the
eastern Sierra and western NV Monday night/Tuesday. JCM

AVIATION...

There is a 40% chance of thunderstorms at all main terminals
(KRNO/KTVL/KTRK/KCXP/KMMH) this afternoon and evening, and then
an equal chance again tomorrow. The main threats from these
thunderstorms are erratic wind gusts up to 40 kts and heavy rain.
Storm coverage and intensity should decrease after 03Z this
evening and again tomorrow evening but scattered showers and a few
thunderstorms could continue overnight both nights.

A cold front passage on Thursday will bring gusty winds and
chances for showers and thunderstorms. Thunderstorms on Thursday
are not expected to be as strong but erratic wind shifts and
brief MVFR conditions will still be possible. JCM

&&

.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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