Red Flag Warning 3, NWS Reno, NV

898 
WWUS85 KREV 300248
RFWREV

URGENT - FIRE WEATHER MESSAGE
National Weather Service Reno NV
748 PM PDT Sat Jul 29 2023

CAZ270-278-NVZ458-300400-
/O.EXP.KREV.FW.W.0003.000000T0000Z-230730T0300Z/
Surprise Valley California-Eastern Lassen County-
Northern Washoe County-
748 PM PDT Sat Jul 29 2023

...RED FLAG WARNING WILL EXPIRE AT 8 PM PDT THIS EVENING FOR
GUSTY WINDS AND LOW HUMIDITY FOR NORTHEAST CALIFORNIA AND
NORTHWEST NEVADA...

Wind speeds will continue to weaken in to the evening with
increasing humidity, lessening fire danger.

$$

http://weather.gov/reno

Area Forecast Discussion
National Weather Service Reno NV
213 AM PDT Sat Jul 29 2023

.SYNOPSIS...

Typical dry summertime weather will round out the month of July
with seasonable warmth and late day breezes. Moisture returns for
the first few days of August, which may be sufficient for
isolated showers and thunderstorms each afternoon starting
Tuesday.

&&

.DISCUSSION...

The trough over the PacNW and ridge across the central/southern
Rockies will keep a dry southwest flow over the Sierra and
western NV this weekend/Monday. Winds will be breezy in the
afternoons and early evenings with some increased chop on area
lakes along with localized fire weather concerns. The upper level
jet across northern CA/northwest NV peaks tonight into Sunday
morning which is not ideally aligned with daytime mixing for
widespread stronger winds. However, simulated gradients in the
CAMs guidance indicate sustained winds 20+ mph for 3-6 hours this
afternoon/early evening over far northeast CA and northwest NV for
critical fire weather concerns. Temperatures will stay close to
averages for late July.

Next week, we continue to see signs of the trough retreating,
allowing for a more southerly flow aloft to return and the
afternoon zephyr weakening. Also, deterministic guidance (00z
GFS/ECMWF) continues to indicate a shortwave lifting northward
across the area Tue-Thu, and this weakness in the ridge is showing
up in the mean 500 MB heights cluster analysis. Initially for
Tuesday, it appears there will be a significant amount of high
clouds which would limit convection, although some drying aloft on
the southern edge of the cloud shield could reach as far north as
Mono-Mineral counties and allow for better instability. As the
thicker cloud layer lifts north Wed-Thu, cooling aloft and
increased forcing associated with the potential shortwave would
provide a better environment for showers and thunderstorms.
National blended guidance shows a 10-20% probability for
thunderstorms Tue-Thu, so our forecast will maintain a low end
chance, starting south on Tue and spreading north Wed-Thu. Some
nocturnal convection cannot be ruled out either, especially
Tuesday and Wednesday nights. ECS/GEFS meteograms show PWATs
climbing to 0.70+ inches, highest across western NV. So any
stronger storms will be capable of heavy rain along with the
lightning and gusty wind potential.

Hohmann

&&

.AVIATION...

VFR with little day-to-day change through Monday. Afternoon
southwest breezes will continue with gusts around 25 kts at most
terminals. There will also be periods of increased ridge level
wind gusts of 35-45 kts producing some mountain wave turbulence.
A return chance of thunderstorms is possible Tue-Thu next week.

Hohmann

&&

.FIRE WEATHER...

* Dry southwest flow will persist through Monday with low
  afternoon humidity (5-15%) and generally poor overnight
  recoveries. Fuels will continue to cure as a result.

* Southwest to west winds will generally remain below critical
  thresholds with the exception of CA fire weather zones 270-278
  and NV fire weather zone 458 today where latest high resolution
  guidance is indicating a 3-6 hour period of sustained winds 20+
  mph between 1 pm and 8 pm. As a result, we have raised a red
  flag warning in these locations. Elsewhere, brief periods (1-3
  hours) of critical conditions are possible where fuels are
  ready.

* Signs continue to point to moisture return and isolated
  thunderstorm potential around the middle of next week, starting
  across Mono-Mineral County as early as Tuesday then spreading
  north Wed-Thu. Right now, a hybrid storm environment is most
  probable with storms capable of new lightning starts/erratic
  gusty winds but also locally heavy rain.

Hohmann

&&

.REV Watches/Warnings/Advisories...
NV...Red Flag Warning from 1 PM this afternoon to 8 PM PDT this
     evening NVZ458.

CA...Red Flag Warning from 1 PM this afternoon to 8 PM PDT this
     evening CAZ270-278.
&&