Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 240939

Area Forecast Discussion
National Weather Service Reno NV
239 AM PDT Mon Jun 24 2024


* It is going to be warm and breezy through much of the week with
  temperatures easing a bit but still slightly warmer than
  average. Winds will be strongest Wednesday and Thursday.

* There is a 10-30% chance of showers and thunderstorms south of
  Highway 50. Best chances will be on Tuesday.

* Temperatures will remain very warm next weekend with typical
  afternoon breezes and little chance for precipitation. These
  conditions are likely to persist into the first week of July.



* A trough pattern over the PacNW and ridge over the southern
  Rockies will continue to bring a rather breezy pattern to the
  area this week with temperatures cooling a few degrees by Thu-
  Fri. The trough advances eastward through the northern Rockies/
  northern Great Basin Wed-Thu as another trough upstream drops
  southeastward through the Gulf of Alaska. This will bring a
  period of enhanced southwest winds Wednesday, shifting to the
  northwest behind a frontal system on Thursday. Some chop can be
  expected on area lakes this week, but a period of rougher lake
  waters, aviation turbulence and fire weather concerns is likely
  Wed-Thu as ridge gusts reach 60+ mph and we see gusts 30-45 mph
  at times for lower elevations. This pattern has been fairly
  consistent the past few days and overall confidence is above

* One thing that continues to evolve is the transport of moisture
  around the periphery of the ridge into the eastern Sierra and
  western NV with latest guidance a bit farther north. Confidence
  is certainly below average on this aspect as we have pushed the
  chance for showers/storms to I-80 Tuesday with a few showers
  reaching Mono-Mineral counties as early as this evening.
  Extensive cloud cover may limit instability and forcing is
  rather diffuse. So we may end up with a lot more clouds and
  showers tonight and Tuesday than storms. Right now, the best
  chances for thunderstorms will be Tuesday afternoon as low
  level convergence increases ahead of incoming trough. The
  moisture may also have ramifications for fire weather as
  guidance shows dewpoints rising considerably. More below in the
  fire section.

* For Friday and beyond, things look to go back to dry and very
  warm with typical daytime breezes. The upstream trough mentioned
  above moves into the PacNW, keeping a dry southwest flow aloft
  over the region and confining any monsoon push to our east.
  These conditions may very well persist into the July 4th weekend
  based on latest ensemble clusters. Like this week, we cannot
  rule out a period of enhanced winds as northern stream energy
  allows troughs to brush the Great Basin.




* Some subtropical moisture will stream into the Sierra and
  western NV later today through Tuesday and increase the risk of
  showers and thunderstorms, especially for areas south and east
  of the Tahoe Basin (including KMMH). There is a 10-20% chance at
  KMMH late this afternoon/evening then storms may move as far
  north as I-80 midday Tuesday before getting shunted eastward
  later in the day (KLOL-KNFL).

* Afternoon/evening breezes will continue today and Tuesday with
  most gusts 20-25 kts and a 2-3 hour window of gusts 25-30 kts.
  Ridge winds were gusting to 50+ kts at times, so expect periods
  of light to occasionally moderate turbulence and even some LLWS
  during the early morning hours.

* A cold front will bring more widespread winds, turbulence and
  LLWS Wed-Thu.




* Dry and breezy conditions again this afternoon/evening. Late
  Sunday, we saw locally critical fire weather conditions in fire
  zone 423. It will be similar today with the best combination of
  wind and low RH extending from the Sierra Front zone 420 to the
  West Humboldt Basin zone 423 where there will likely be a 2-4
  hour period of near critical wind/RH.

* Models continue to advance moisture northward into the eastern
  Sierra and western NV tonight and Tuesday with latest guidance a
  bit farther north. We have introduced a low-end chance of
  lightning near Mammoth Lakes and the White Mts late this
  afternoon (10-20% chance), but the best chance will be Tuesday
  as moisture streams northward and deepens. The one caveat will
  be instability as clouds thicken up and limited heating. Still,
  we believe there will be enough heating to get isolated storm
  coverage with best chances across Mono-Mineral-southern Lyon
  counties (15-30% chance) and more isolated elsewhere. It will
  continue breezy over northwest NV where drier air will remain in
  place for locally critical fire weather (north of I-80).

* Our big concern will be Wed-Thu as the next trough approaches
  and southwest winds increases with widespread gusts 25-35 mph.
  The most critical areas will be in fire zones 278-458-423 where
  RH levels will be low enough (10-15%) for critical conditions.
  For Zone 420, RH levels look to stay up around 20%, but any
  change could quickly push the Sierra Front into critical fire
  weather. After additional coordination with the area GACCs later
  this morning, a watch issuance is likely (70% chance). On
  Thursday, gusty north winds and very dry air may bring portions
  of the Basin and Range (especially south of Hwy 50) the near
  critical levels behind the front.



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