Severe Thunderstorm Warning 25, NWS Reno, NV

338 
WWUS55 KREV 262241
SVSREV

Severe Weather Statement
National Weather Service Reno NV
341 PM PDT Sun Jul 26 2020

CAC003-262315-
/O.CON.KREV.SV.W.0025.000000T0000Z-200726T2315Z/
Alpine CA-
341 PM PDT Sun Jul 26 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM PDT
FOR ALPINE COUNTY...

At 338 PM PDT, a severe thunderstorm was located near Ebbetts Pass 
and is nearly stationary.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, fencing and trees. 
         Accumulating hail and heavy rain along Highway 4 near 
         Ebbetts Pass. Strong outflow winds from this storms may 
         push into Douglas County.

Locations impacted include...
Grover Hot Springs, Markleeville, Junction CA 89 And CA 4, Turtle
Rock Campground, Indian Creek Campground, Indian Creek Reservoir and
Alpine County Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of 
a building. 

&&

LAT...LON 3858 11985 3866 11993 3877 11976 3852 11962
      3850 11975
TIME...MOT...LOC 2238Z 246DEG 2KT 3860 11981 

HAIL...0.75IN
WIND...60MPH
 
$$

BB

Area Forecast Discussion
National Weather Service Reno NV
253 AM PDT Sun Jul 26 2020

.SYNOPSIS...

Increasing thunderstorm coverage is expected today into northwest
Nevada and northeast California, likely lasting overnight, with
more widespread storms on Monday. Drier conditions along with
typical afternoon breezes and summer heat is expected Tuesday
through the end of next week.

&&

.SHORT TERM...

Deepening low pressure off the coast of California will create
additional forcing for thunderstorms today through Monday with
increasing thunderstorm coverage today and Monday. Sufficient
instability and upper level forcing is expected to sustain
thunderstorms through the overnight hours tonight, mainly in
northwest Nevada and Northeast California, north of I-80. For more
info on the fire weather implications, read the fire weather
section below.

The deepening low pressure along the coast will create southeast
flow over the region today with storm motions increasing to around
10-15 mph. An upper level wave moving over the area will give
forcing for storms to initiate in western Nevada and northeast
California, in addition to storms forming in the Sierra. A second
wave overnight, along with increasing jet level winds, and upper
level divergence, will likely keep at least a few elevated storms
going through the overnight hours north of I-80.

A final upper level wave is forecast to move through the region
on Monday with another day of fairly widespread thunderstorm
activity. With the added forcing, storms are expected to form much
earlier in the day then our typical pattern of thunderstorms
initiated from heat and convergence along the terrain. The jet
streak will be pushed into eastern Nevada by then, but good mid-
level instability will remain. Storm coverage is expected to by
most prevalent in the Sierra and northeast California, and
western Nevada north of I-80.

A break in the thunderstorm activity is expected to start on
Tuesday with a return to average summer temperatures and typical
afternoon breezes. -Zach

.LONG TERM...Wednesday into next weekend...

Not many changes in the long term with breezy conditions midweek
followed by some heat for next weekend. An upper low will get
ejected through northern California Wednesday with an increase in
winds, but timing will dictate how strong the winds will be.
Thursday still looks breezy with southwest flow and a deeper upper
trough off the Pacific Northwest coast. Then it looks to be more
typical afternoon zephyrs into the weekend.

As for temperatures, they look to be near average Wednesday and
Thursday before warming a few degrees above average for next
weekend. Some ensemble members are showing decent triple digit heat
for parts of western Nevada for early August so this will be
watched. No precipitation is expected for the long term.

&&

.AVIATION...

Isolated thunderstorms will continue to be the main concern into
Monday. The best chances will be around KMMH (20-25%), with lesser
chances for the Tahoe/Sierra Front terminals (~15%). Gusty outflow
winds to 40kts are the biggest concern along with small hail.
Outside of thunderstorm winds winds will be a bit more south today
and Monday with peak gusts around 20 kts. Better chance of
thunderstorms for Monday from KTVL-KMEV northward with chances
around 30% and remaining around 20% for KMMH. X

&&

.FIRE WEATHER...

Thunderstorms will increase a bit more today, and will move more,
from south to north around 10 mph. Storms are still expected to be
mainly wet, but cores will not be all that big with a few dry
strikes remaining possible.

The main concern continues to be Monday morning through Monday
evening. Two more short waves are expected to move through ahead of
the offshore upper low. One around sunrise with another during the
afternoon. Upper level instability is there along with some forcing,
but the mid-level moisture isn't ideal. Still expect isolated storms
forming around 3-5 am from Highway 50 northward and many convective
allowing models are showing this scenario. These storms would be
fast movers (20+ mph) and drop only light rainfall. In the afternoon
most models are showing scattered thunderstorms from the Tahoe Basin
and northern Sierra Front toward the Oregon border. Storm motions
will be slower, but still expecting more hybrid storms with numerous
new fire starts possible. Will continue to interrogate this morning
and may upgrade to a Red Flag Warning. More isolated storms are
expected south of Highway 50.

Then it will turn breezy by Wednesday/Thursday with gusts of 30-40
mph possible both days. Wednesday has about a 50-60% chance of
seeing these winds while Thursday is a bit less at 30%. Either way,
a significant dry slot will move in by Wednesday afternoon with
single digit RH in the lower valleys and mid teens in the Sierra. RH
recovery will be poor with the Tahoe Basin having a 75% chance of
seeing significant RH drops (15-20+%) overnight. X

&&

.REV Watches/Warnings/Advisories...
NV...Fire Weather Watch from late tonight through Monday evening
     NVZ420-423-458.

CA...Fire Weather Watch from late tonight through Monday evening
     CAZ270>272-278.

&&

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

Special Weather Statement
National Weather Service Reno NV
320 PM PDT Sun Jul 26 2020

CAZ071>073-NVZ001>004-270015-
Lassen-Eastern Plumas-Eastern Sierra Counties CA-
Greater Lake Tahoe Area CA-Mono CA-
Western Nevada Basin and Range including Pyramid Lake NV-
Greater Lake Tahoe Area NV-Greater Reno-Carson City-Minden Area NV-
Mineral and Southern Lyon Counties NV-
320 PM PDT Sun Jul 26 2020

...Thunderstorms developing over the Sierra and western Nevada...

Several thunderstorms are developing over the Sierra, including the
Lake Tahoe Basin, and much of western Nevada. Gusty outflow winds in
excess of 40 mph, small hail, dangerous lightning and some rainfall
will occur with these storms.

Now is the time to consider a Plan B for outdoor activities through
the rest of this evening. Strong outflows may lead to areas of
blowing dust across western Nevada. Slow moving storms in the Sierra
could produce accumulating hail and a sudden drop in temperatures.

Locations impacted include... Reno, Carson City, South Lake Tahoe,
Stampede Reservoir, Squaw Valley, Tahoe City, Gardnerville, Virginia
City, Topaz Lake, Sonora Pass, and Dayton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

During a thunderstorm, seek shelter inside a sturdy structure and
stay away from windows. Hikers and campers should seek shelter in a
vehicle if possible. If on or near a lake, get out of the water and
move indoors or inside a vehicle. Don't be caught on the water in a
thunderstorm. Strong wind gusts and lightning pose an immediate
danger to boaters.

&&

LAT...LON 3956 11962 3846 11894 3818 11959 3819 11962
      3835 11963 3845 11968 3869 11998 3881 12003
      3885 12016 3920 12025 3943 12037 3949 12044
TIME...MOT...LOC 2214Z 126DEG 10KT 3890 11971

BB