Special Weather Statement, NWS Reno, NV

Area Forecast Discussion
National Weather Service Reno NV
207 PM PDT Mon Aug 7 2017

.SYNOPSIS...

Low pressure stalled over northern California will produce
thunderstorms through midweek with heavy rainfall possible. Drier
weather returns late in the week through next weekend. Temperatures
will remain slightly below average through Wednesday, followed by
some warming.

&&

.SHORT TERM...

Today through Wednesday there is a risk for flash floods from
afternoon/evening thunderstorms with the highest risk near steep
terrain, recent burn areas, and any locations that received heavy
rain over the last few days.

A weak upper low over northeast CA is evident in radar and
satellite imagery this afternoon as showers and thunderstorms are
moving counter-clockwise around the center of the low. The air
mass over the Sierra and western NV is not as unstable today as
yesterday and thunderstorms are taking longer to develop, but
ample moisture is still in place and we can't rule out a few
stronger storms late this afternoon and this evening with heavy
rain and additional street flooding or mud/rock slides possible.

Tuesday and Wednesday should be more active in terms of stronger
thunderstorms as an upper Low over northwest CA shifts east. This
pattern puts the eastern Sierra and western NV under a diffluent
zone which is a classic thunderstorm pattern for us. For Wednesday
additional moisture is also transported eastward into the area,
especially north of I-80 where precipitable water values up to an
inch are expected. Some computer simulations show an upper-level
impulse could also track over the area Wednesday
afternoon/evening. The track and timing of this impulse is
uncertain, but if it arrives during the afternoon it could lead to
stronger and more numerous severe storms Wednesday. JCM

.LONG TERM...Thursday through early next week

A drier southwest flow Thursday-Friday should push the deeper
moisture north of the Oregon border. There is a slight chance for
enough lingering moisture for perhaps a shower or thunderstorm or
two north of Susanville-Gerlach and possibly also in Mineral
County. The air mass continues to dry going into the weekend and
mostly sunny afternoons should provide a warming trend to slightly
above average temperatures for the weekend.

There may be a slightly cooler period with typical
afternoon/evening Zephyr breezes early next week as the models are
trending toward an upper low somewhere off the coast or over the
Pacific Northwest. With this pattern the southwest monsoon
moisture would be over Arizona, so a significant return of moisture
is not expected for the Sierra or western Nevada through early
next week. JCM

&&

.AVIATION...
Scattered thunderstorms are expected today through Wednesday. For
this afternoon and evening the best coverage will be north of
I-80. The chance for a storm today at a KTVL/KMMH is 25% and
at KTRK/KCXP/KRNO is 30-40%. The main threat today is heavy rain
and mountain obscuration, but hail around 1/2" in diameter and
wind gusts to 40 kts are also possible. Peak period for storms
today for the Sierra and Sierra Front is 21-01Z and a few hours
later (00-04z) for the terminals along Highway 95
(KLOL/KNFL/KHTH). JCM

&&

.FIRE WEATHER...

Scattered wet storms are expected today through Wednesday. For
today and Tuesday most storms should produce 1/4 to 1/2" with
locally heavier amounts possible. Wednesday has the best potential
for more numerous and stronger storms. Even though the storms are
wet, a few strikes remain possible outside the rather large
cores. As we saw yesterday, with the heavy fine fuel loads, fires
will still be possible and capable of rapid rates of spread due
to outflow winds. JCM

&&

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

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

Special Weather Statement
National Weather Service Reno NV
141 PM PDT MON AUG 7 2017

CAZ071-072130-
Lassen-Eastern Plumas-Eastern Sierra Counties CA-
141 PM PDT MON AUG 7 2017

...Thunderstorms approaching Eagle Lake...

At 135 PM PDT, Doppler radar was tracking thunderstorms just west of
Eagle Lake, moving east at 5 to 10 mph.

Wind gusts to 35 mph and a few cloud to ground lightning strikes are
possible on Eagle Lake between 150 PM and 230 PM as the
thunderstorms move over or near the lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If on Eagle Lake, get out of the water. Remember, lightning can
strike out to 10 miles from the parent thunderstorm. If you can hear
thunder, you are close enough to be struck by lightning. Do not be
caught on the water in a thunderstorm!

Strong wind gusts and lightning pose an immediate danger to boaters.
Gusty winds could cause a rapid increase in wave heights which may
capsize small boats.

&&

LAT...LON 4054 12093 4072 12098 4093 12073 4069 12064
      4054 12075
TIME...MOT...LOC 2035Z 258DEG 13KT 4065 12087

SS

Special Weather Statement
National Weather Service Reno NV
427 PM PDT MON AUG 7 2017

CAZ071>073-NVZ001>005-080045-
Lassen-Eastern Plumas-Eastern Sierra Counties CA-
Greater Lake Tahoe Area CA-Mono CA-Greater Lake Tahoe Area NV-
Western Nevada Basin and Range including Pyramid Lake NV-
Northern Washoe County NV-Greater Reno-Carson City-Minden Area NV-
Mineral and Southern Lyon Counties NV-
427 PM PDT MON AUG 7 2017

...THUNDERSTORMS OVER NORTHEAST CALIFORNIA AND FAR WESTERN NEVADA...

At 421 PM PDT, isolated thunderstorms were ongoing over northeast
California and far western Nevada. Thunderstorms were moving to the
east or east-northeast at around 5 to 10 mph. Wind gusts to 40 mph,
brief heavy rain, pea-size hail, and occasional cloud to ground
lightning will be possible with storms into early evening.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If on a lake, get out of the water. Don't be caught on the water in
a thunderstorm. Strong wind gusts and lightning pose an immediate
danger to boaters. Hikers and campers should seek shelter if
possible. Tents and trees are unsafe shelters during thunderstorms.

&&

LAT...LON 4089 11980 3969 11907 3857 11966 3924 11995
      3919 12014 3956 12029 3981 12062 4066 12122
TIME...MOT...LOC 2321Z 258DEG 0KT 3963 12039

SS