Dense Smoke Advisory 3, NWS Reno, NV

Area Forecast Discussion
National Weather Service Reno NV
337 AM PDT Sun Aug 16 2020

.SYNOPSIS...

Isolated to scattered showers and thunderstorms can be expected
each afternoon through the middle of the week. Hot temperatures
are forecast through the week with heat impacts possible for
sensitive groups and those with limited cooling options for their
homes.

&&

.SHORT TERM...

* Nocturnal convection is moving up through the Bay Area and
  northern California this morning. These storms are expected to
  push through the northern Sierra and northeast California by late
  this morning.

* Thunderstorm activity will increase by this afternoon across the
  rest of the forecast area as temperatures heat up. Strong storms
  will be capable of producing winds gusts over 50 mph, small hail,
  and a brief periods of heavy rain. The flash flooding and debris
  flow threat appears to be rather low due to faster storm motions,
  though any slower moving storms could easily drop a burst of heavy
  rain which would be a threat near burn areas or in steep, sparsely
  vegetated terrain. A Red Flag Warning has been issued for the
  combined potential of new lightning starts and gusty outflow winds
  from thunderstorms today. Please see our fire weather discussion
  below for additional information.

* Heat Advisories have been issued through Tuesday evening for the
  western Nevada zones and Surprise Valley. Above normal temperatures
  continue across the region for the next several days. Yesterday,
  we hit a tied a record high temperature at the Reno-Tahoe
  International Airport with 102 degrees, which matched a 102 degree
  day back in 1933. Temperatures will be a few degrees cooler today,
  although still well above normal with temps near 100 degrees in
  the desert valleys and highs near 90 in the Sierra. Warm overnight
  temperatures are being seen all across the region this morning due
  to abundant cloud cover. The combined heat and mild overnight lows
  will bring heat impacts to sensitive populations, those exposed to
  the afternoon sun for long periods of time, and to those who do
  not have adequate home cooling. If you have outdoor plans be
  prepared for the heat and definitely carry extra water if you are
  going to be outside for several hours.

* Strong high pressure remains over the Great Basin through the
  first half of this week with well above normal temperatures and
  chances for afternoon and evening showers/thunderstorms. Storms
  will initiate over the higher elevations of the Sierra and
  northeast California and move off to the north and east into
  western Nevada through the late afternoon and evening hours. -Hoon

.LONG TERM...Tuesday through next Sunday...

Only minor changes were made in this forecast cycle. The main foci
in the long term are when we will get a reprieve from this heat and
when chances for thunderstorms decrease.

* Heat: Model guidance is still in agreement that the hottest days
  will be Tuesday and Wednesday across the Sierra and western Nevada
  as the center of the anomalously strong ridge comes closest to our
  area. Afternoon highs will be in the mid-90s to low-100s for
  western Nevada valleys and 80s to around 90 in Sierra valleys.
  Residual subtropical moisture will limit radiational cooling
  Wednesday morning, so lows will struggle to get below the mid-to-
  upper 60s in western Nevada. However, the good news is that by
  late Wednesday into the early part of the weekend the ridge begins
  to retreat to the Desert Southwest as a strong Gulf of Alaska
  trough moves near the Pacific Northwest. Ensembles are in good
  agreement that we will gradually cool into the weekend to a few
  degrees above normal instead of the 7+ degrees above normal we
  will be seeing this week. Heat-health impacts will likely continue
  with the prolonged above normal heat. As always, limit your
  outdoor exposure and recognize the symptoms of heat-related
  illness.

* Thunderstorms: Convection begins to move south and east through
  the late part of the week as the subtropical moisture plume begins
  to move east as the ridge retreats to the Desert Southwest.
  Afternoon thunderstorms will be mainly restrained to the Eastern
  Sierra and portions of western Nevada south of US 50 where
  moisture convergence will be focused. By Friday and Saturday, the
  stronger southwesterly flow aloft will likely push the locus for
  convection out of Mono and Mineral counties and over northern Nye
  County.

* Wind: Typical zephyr breezes will be present through the latter
  half of the week with gusts to around 20-25 mph each afternoon.

-Johnston

&&

.AVIATION...

Isolated to scattered showers and thunderstorms to develop each day
through early next week between 20z-04z. Note that a few showers or
thunderstorms are also possible early today in eastern CA and
extreme wrn NV as an upper wave moves by. Afternoon and evening
thunderstorms could bring outflows 35-45 kts, small hail, and
brief moderate to heavy rain. Overnight storms could bring sudden,
erratic gusts to 35 kts with little or no rainfall.

Smoke and haze from the Loyalton Fire may limit flight visibility
(terrain obscuration) around the eastern Sierra Valley up to around
Doyle at least for the next couple days. -Snyder/Hoon

&&

.FIRE WEATHER...

We have upgraded to Red Flag Warnings for today for the the risk of
fast moving thunderstorms producing lightning capable of new fire
starts and gusty outflow winds, with only short periods of rainfall.

High resolution model guidance (especially the HRRR) continues to
indicate potential for convection across northeast CA, northwest and
far western NV starting around mid morning and pushing north through
early afternoon.

Then during the afternoon, additional showers and thunderstorms are
projected to develop across western NV and portions of the eastern
Sierra. The main concern is that these cells will be relatively fast
moving with high cloud bases limiting precipitation amounts. The
uncertainty remains as to how much lightning will occur with the
morning-midday activity, while the afternoon storms may become
wetter and move a little slower. With the extreme activity on the
Loyalton fire observed yesterday and similar overall weather
conditions expected on Sunday, any new fire starts would have the
potential for rapid growth.

Another round of thunderstorms is expected on Monday, although it
appears that storm motion will be a little slower with increasing
moisture, resulting in a transition to wetter storms. Still,
lightning strikes outside precipitation cores could produce a few
new fire starts, while outflow gusts near existing fires could
produce hazardous conditions and rapid growth.

Thunderstorm potential will slowly decrease as we get to mid-late
week, but with above average temperatures, overall dry conditions
and some afternoon zephyr breezes along with probable ongoing fires,
elevated fire weather concerns are likely for the next several days.
-MJD/Hoon

&&

.REV Watches/Warnings/Advisories...
NV...Red Flag Warning from 9 AM this morning to 9 PM PDT this evening
     NVZ420-458.

     Heat Advisory until 11 PM PDT Tuesday NVZ001-003>005.

     Red Flag Warning from 1 PM this afternoon to 9 PM PDT this
     evening NVZ421-423-429.

CA...Red Flag Warning from 9 AM this morning to 9 PM PDT this evening
     CAZ270-278.

     Heat Advisory until 11 PM PDT Tuesday CAZ070.

     Red Flag Warning from 1 PM this afternoon to 9 PM PDT this
     evening CAZ274.

     Red Flag Warning from 9 AM this morning to 7 PM PDT this evening
     CAZ271-272.

&&

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