Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 272114

Area Forecast Discussion
National Weather Service Reno NV
214 PM PDT Tue Sep 27 2022


Warm Fall days and cool nights to continue this week. Breezy winds
this afternoon will be stronger on Wednesday with fire weather and
recreation concerns. A few isolated light showers will form again
this afternoon from the eastern Sierra front into portions of
western Nevada, mainly south of I-80.


.SHORT TERM...through Wednesday Night...

* Late September warmth continues, though we will see a few degrees
  of cooling after today.

* PWATs are beginning to trend downward, but there is enough
  remnant moisture and instability to pop a few additional
  isolated showers this afternoon. Given the depth of the moisture
  response in forecast simulations, showers are likely to be
  rather shallow and it`ll be hard to see a thunderstorm develop,
  only a 5% chance. Most activity will yield only virga or light
  precipitation totals of a few hundredths of an inch. Showers are
  likely to be focused near and south of US-50, through a stray
  shower may reach I-80, with an eastward progression this
  afternoon due to increasing westerly winds.

* We`ll see some increase in southwest-west winds this afternoon
  with gusts reaching 20-30 mph. Further increases are expected
  Wednesday afternoon as a trough moves into the PacNW coast.
  Latest ensemble meteogram guidance, in addition to operational
  models and the NBM, have all trended upward with wind speeds.
  This is especially true along the Sierra Front in addition to
  areas north of I-80 in western Nevada where gusts may reach 40

* With the stronger winds and drier conditions there are fire
  weather concerns. Please see the Fire Weather Section below for
  additional details. Winds will also bring choppy conditions to
  area lakes and a Lake Wind Advisory has been issued for Pyramid
  Lake Wednesday afternoon and early evening.


.LONG TERM...Thursday onward...

Relatively benign weather is expected through the remainder of the
forecast period. Gusty winds up to 30-40 mph are expected to persist
overnight and into Thursday afternoon for Sierra ridges. Elsewhere,
winds will drop off overnight, with some slightly elevated gusts
between 20-25 mph on Thursday afternoon. Following the shortwave
trough passage to our north, cooler northwesterly flow will develop
over the region on Thursday. This will allow for a brief gradual
cooling trend through the end of the week, with highs reaching
seasonal averages by Saturday.

A ridge will begin building over the western US on Sunday. This
pattern looks to remain through the end of the forecast period,
keeping conditions dry with above-average temperatures through
midweek next week.




Overall, VFR conditions will prevail through the period. Cumulus
buildups with isolated showers are expected to develop this
afternoon, mainly across Mono/Mineral/Churchill counties. Showers
will track east-northeast across the region through the evening.
There is a low chance (5-10%) for a stray thunderstorm to pop in
Mono or Mineral counties between 21-00z.

An upper-level trough passing to our north will bring enhanced
afternoon winds tomorrow for all regional terminals. Gusts to 30-
35 kts are expected. Sierra terminals (KTRK-KTVL) may see lower
level wind shear between 09-15z tomorrow as gusty southwest winds
to 35 kts at mountain top heights are expected to develop before
mixing occurs.




* Wind speeds have trended upward for Wednesday afternoon,
  particularly along the eastern Sierra front and portions of
  northwestern Nevada near and north of I-80. Wind gusts of 30-40
  mph are expected from approximately noon through 8 pm,
  corresponding with minimum humidity values in the 10-18% range.

* We have issued a Red Flag Warning from 1 pm to 8 pm Wednesday
  for eastern Lassen County, the Surprise Valley, and northern
  Washoe County. The EC EFI is showing the strongest signal for
  peak wind gusts in these areas, in addition to where the HREF
  combined probabilities are hitting sustained winds 20+ mph and
  RH < 15%. These locations have the strongest winds along with
  lowest humidity, overlapping with where fuels remain critical.

* While many areas have seen wetting rains recently, along with
  higher humidity values, intel from local partners on fuels status
  indicate that larger fuels (100 hr +) remain critical in the areas
  where the Red Flag was issued, with much of the moisture response
  limited to smaller fuels.

* Fire zone 423 (West Humboldt Basin - Pershing Co) will see
  critical conditions as well, but per intel, fuels are not
  critical. We`ll also be close along the northern and southern
  Sierra Front with localized critical conditions.



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

     Lake Wind Advisory from 1 PM to 8 PM PDT Wednesday for Pyramid
     Lake in NVZ004.

CA...Red Flag Warning from 1 PM to 8 PM PDT Wednesday CAZ270-278.


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