Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 250955

Area Forecast Discussion
National Weather Service Reno NV
255 AM PDT Wed May 25 2022

Record highs today along with isolated showers and possibly a few
thunderstorms. Elevated fire concerns will exist on Thursday,
particularly for lower elevations with dry grasses with additional
showers and storms possible across the Great Basin. Breezy winds
will persist from Thursday through Memorial Day Weekend, along with
cooler temperatures, some showers and possible thunder. A few
snow showers are also possible in the Sierra Sunday and Monday.


.SHORT-TERM (Through Thursday Night)...

* Temps: The short-term period will be "hot hot hot" with
  temperatures well above average with respect to late May. Almost
  no change in the forecast thinking concerning temperatures over
  the next couple of days. Highs today will flirt with Reno`s
  daily record of 92, Tahoe City`s 80, and South Lake Tahoe`s 83.
  Out of these three cities, Reno will have the best shot at
  meeting or exceeding its record. Thursday looks to be only
  slightly cooler (by a few degrees) across the Sierra and the
  Sierra Front, but may actually be a hair warmer over
  Pershing/Churchill/Mineral counties as the ridge axis shifts
  eastward. Low temperatures will also be mild across the region
  with morning temperatures running 5-15 degrees above average.

* Winds: While nothing substantial, impactful winds look to arrive
  by Thursday and might just hang around through at least Sunday
  (see long-term discussion for the weekend`s outlook). With an
  uptick in boating activities likely starting to ramp up for
  those who managed to sneak out of work a few days early, there
  is increasing confidence in poor marine conditions on Thursday.
  Memorial Day Weekend is typically the initiation of when we`ll
  issue Lake Wind Advisories beyond just Tahoe/Pyramid. Given the
  extended duration of gusty conditions lasting into the weekend,
  it appears prudent to go ahead and start these a day or 2 early.
  Friday, winds will remain elevated south of US-50 but likely
  remain just below advisory criteria so only Washoe/Rye
  Patch/Lahontan/Pyramid will continue through Fri. For more
  details on how this relates to elevated fire weather concerns,
  please see the related discussion below.

* Convection: The forecast still calls for isolated showers with a
  few rumbles of thunder today with abundant surface heating and
  low-level convergence along the Eastern Sierra Front and Lassen
  county aiding in plenty of towering Cu development and a few Cb
  with the stronger updrafts. These will traverse northeastward
  throughout the day. Heavy precip will be hard to come by due to
  dry air and their high bases, but this could aid in gustier
  winds and more concern for lightning started fires. Development
  of showers and isolated thunder looks to repeat itself on
  Thursday afternoon, but likely initiating near and east of US-95
  in western Nevada where the greatest instability and moisture
  will overlap.

.LONG TERM (Friday Through The Remainder of May)...

Call it a tradition, quirk or a jinx, but the infamous history of
having less than optimal outdoors weather in eastern CA-western NV
for Memorial Day weekend appears to be setting up again this year.

Friday is looking dry with gusty winds similar to Thursday and
some cooling from the mid-week heat, but still above average
(highs upper 70s-lower 80s for western NV valleys and near 70 for
Sierra valleys).

However, the trends continue toward cooler and increased shower
chances for much of the Memorial Day weekend. While a couple of
days ago the cooler and wetter scenario was indicated by only
10-20% of the ensemble guidance simulations, currently more than
half are showing this scenario. In addition, the upper low
responsible for these shower chances could linger through more of
Monday as well.

While the details are likely to change as we get closer to the
weekend, Saturday still shows the best chance for showers and
isolated thunder for northeast CA-northwest NV, with a couple
stray showers possibly reaching the Tahoe basin. Gusty winds
remain on the table as well, with speeds similar or even slightly
stronger than Thursday-Friday.

Sunday and Monday are shaping up to have temperatures 10-15
degrees below average, resulting in highs mainly in the 60s for
lower elevation and 50s for Sierra valleys. Lows could bottom out
in the upper 20s-lower 30s near the Sierra, and upper 30s-lower
40s in western NV for early morning Monday and Tuesday. Breezy
winds will continue although speeds are expected to decrease from
Saturday. While precip amounts look to be light with travel
impacts unlikely on the main passes, this cooler trend does
warrant a mention of snow levels which range from 7000-7500 feet
Sunday afternoon-evening, and possibly to near 6000-6500 feet by
Monday morning. We have already recommended packing winter
clothing for those planning outdoor activities especially for the
Sierra, and we can`t rule out a touch of snow in the air and on
unpaved surfaces around the Tahoe basin and eastern Sierra
locations for early risers on Monday.

After the holiday weekend ends, temperatures begin to rebound
Tuesday with precip chances decreasing, although a small
percentage of the model simulations attempt to slow the departure
of the upper low, so leftover clouds and stray showers aren`t
fully out of the picture yet. MJD



Zephyr breezes develop this afternoon in the Sierra and far western
NV with peak gusts near 20-25 kts. Warming temperatures will bring
a 10-15% chance for PM -TSRA across parts of western NV, mainly
east of the main terminals. Cumulus buildups start to build around
21 UTC along RNO-MEV-MMH then push to the east toward LOL-NFL-HTH
as the zephyr breezes develop. Stronger storms may produce gusty
outflow winds to 40 kts.

For Thursday-Friday, winds increase with gusts 25-35 kt at the main
terminals with turbulence and mountain wave activity developing.
The winds may edge upward even more on Saturday as an upper level
jet streak moves overhead. MJD



Atmospheric conditions (windy, warm, and dry) will combine on
Thursday to produce an elevated fire weather concern across the
Eastern Sierra Front and much of western Nevada. Overall fuel
status outside of critical levels will preclude the issuance of a
RFW, but initial attack of new fire starts will be more difficult
in the lower elevations where some finer fuels have locally
cured. For Thursday:

Temps: Highs in the low 90s over western Nevada and Chalfant
Valley. Warmest temperatures in Dixie Valley with highs in the
mid/upper 90s.

RH: Poor overnight RH recovery tonight into Thursday morning of
25-40% across western Nevada and portions of Eastern Sierra Front.
Afternoon minimum relative humidity values of 10-20% with a few
warmer valleys across the Great Basin possibly dipping into single

Winds: Sustained out of the west at 15-25 mph with widespread
gusts of 35-45 mph. Isolated gusts on the order of 50 mph
possible in wind prone areas, and the higher elevations of the
Sierra Front.

Thunder: Isolated showers and a few thunderstorms will develop
Thursday afternoon, primarily east of US-95 on Thursday. Due to
very strong mixing heights, these will likely produce little
rainfall and will be more prone to cause new fire starts. Gusty
outflows will of course be possible as well...


.REV Watches/Warnings/Advisories...
NV...Lake Wind Advisory from noon to 8 PM PDT Thursday NVZ002.

     Lake Wind Advisory from noon to 8 PM PDT Thursday NVZ001.

     Lake Wind Advisory from noon Thursday to 8 PM PDT Friday for
     Washoe Lake in NVZ003.

     Lake Wind Advisory from noon Thursday to 8 PM PDT Friday NVZ004.

CA...Lake Wind Advisory from noon to 8 PM PDT Thursday CAZ071.

     Lake Wind Advisory from noon to 11 PM PDT Thursday CAZ073.

     Lake Wind Advisory from noon to 8 PM PDT Thursday CAZ072.



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