517
FXUS65 KREV 160929
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
229 AM PDT Sun Jun 16 2024

.SYNOPSIS...

* Gusty winds will impact fire potential and recreation this
  afternoon and evening. Gusty winds will persist for areas south
  of Hwy 50 Monday.

* Much cooler conditions Monday and Tuesday. Tuesday morning lows
  will dip below freezing in Sierra valleys and near freezing for
  colder western NV valleys.

* Warming trend for the second half of the week. Daytime highs for
  lower elevations will return to the 90s to around 100 by next
  weekend.

&&

.DISCUSSION...

Enhanced Breezes Today...

* A weather system dropping southeast into the Pacific Northwest
  will swing a dry trailing edge of an attendant dry cold front
  across northern CA-NV. Hi-Res ensemble guidance projects
  increasing west-southwest winds ahead of the incoming system
  that contributes to wind gusts to 35-40 mph (50+ mph over
  Sierra Ridges) this afternoon that continues overnight through
  Monday morning.

* Impacts to boating activities will surface 1-2 PM. With the
  enhanced breezes and continued dry conditions its advised to
  remain vigilant to prevent any sparking that leads to fire
  starts. Winds will shift to the northwest and north as the
  weather system passes further east into the central Great Basin.
  Winds may be slow to decouple and decrease with 30 mph gusts
  persisting through the overnight hours through Monday morning.
  In fact north winds will remain rather breezy for the Chalfant
  Valley into Mineral County Monday afternoon.

Cooler Monday and Tuesday...

* Following passage of the weather system, look for a few days of
  relief from the early summer heat with afternoon highs dropping
  into the mid to high 60s for Sierra locations, and mostly 70s
  for Monday and Tuesday in western NV valleys.

* Light winds, little cloud cover, and dry air will encourage
  additional radiative cooling at the surface, and allow
  temperatures to drop into the mid-upper 20s in many Sierra
  valleys.

* Across western NV there is a 10-20% chance of reaching freezing
  temperatures for cooler locations like the Carson and Smith
  valleys. Urban areas will still feel the refreshing morning
  chill Tuesday AM with lows in the 40s.

Summer Rises Once More...

High pressure builds into the West Coast through the second half
of this week. The widespread subsiding air will not only coax
drier conditions, but also return daytime highs to the more
summer-like 90s by next weekend. A few lower western NV valleys
may see afternoon highs topping the century make as well. Summer
always finds a way to bump that heat engine up. Some ensemble
simulations are even showing a slight increase in thunderstorm
chances (~10%) over the Sierra and western NV through the latter
half of the week. -Amanda

&&

.AVIATION...

* Breezy conditions return today with west-southwest winds gusting
  to 20-25 kts by late morning today after 17-18Z. Winds gusts
  will increase to 30-35 kts after 20-21Z as the dry trailing edge
  of a cold front passes across northern CA-NV this evening and
  overnight. Otherwise, expect persistent VFR flying conditions
  through the forecast period. Cooler, below average temperatures
  will mitigate elevated density altitude issues til mid-week.

* Wind gusts will edge near 50-55 kts over Sierra Ridges with
  developing mountain waves east of the Sierra crest that
  encourage bumpy departures/arrivals from Sierra and western NV
  main terminals. Winds shift to the northwest and north overnight
  Sunday and early Monday with gusts 25-30 kts persisting into
  Monday across western NV. - Amanda

&&

.FIRE WEATHER...

* We have upgraded the fire weather watch to a warning for the
  Sierra Front and Western Nevada Basin & Range mid afternoon into
  this evening. Latest HREF and ECMWF EFI show a signal for a
  critical combination of gusty winds and low RH (west-southwest
  winds 15-25 mph with gusts to 30+ mph and RH 8-15%).

* Winds will begin to increase late morning and early afternoon
  and enhance further during the late afternoon as gradients
  tighten and winds aloft increase ahead of incoming trough. A
  cold front will swing through this evening and begin to turn
  winds to the northwest. Cooler air will allow for humidity to
  slowly rise after sundown, but winds will likely remain elevated
  through the night. Duration of critical conditions will average
  2 to 4 hours, but will locally last up to 6 hours.

* Another period of critical conditions is possible across the
  Chalfant Valley and Mineral County (where fuels are receptive)
  Monday as northerly gradients remain strong and humidity levels
  stay low.

Hohmann

&&

.REV Watches/Warnings/Advisories...
NV...Red Flag Warning from 2 PM this afternoon to 11 PM PDT this
     evening NVZ420-423-429.

     Lake Wind Advisory from 2 PM this afternoon to 11 PM PDT this
     evening NVZ001-003-004.

CA...None.

&&

$$