National Weather Service Raw Text Product

679 
FXUS65 KREV 211929
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
1229 PM PDT Sun Jul 21 2024

.SYNOPSIS...

* Temperatures will continue to run above late July averages with
  100-105 for W.NV and near 90 for Sierra valleys. Continued 
  moderate-major HeatRisk. 

* Daily thunderstorm chances through Thursday. Storms will be 
  trending wetter through the week with increased chances for 
  localized heavy rainfall and flash flooding.

* A cooling trend will arrive for the second half of the week with
  highs returning to near average. Overall drier and breezier
  conditions expected. 

&&

.DISCUSSION...

HEAT: 

* Hot weather will continue through midweek with high temperatures
  100-105 across western Nevada valleys and upper 80s to near 90
  for Sierra communities. This is around 4-8 degrees above season
  averages and could approach daily records. 

* Overnight lows will remain mild as well (10 degrees above avg),
  with W.Nevada valleys only cooling into the upper 60s to low
  70s. This will result in areas of moderate to major HeatRisk so
  be sure to take all your necessary heat precautions. 

INCREASING THUNDERSTORM POTENTIAL: 

* Today: 

  - Afternoon thunderstorms will again fire across the eastern
    Sierra and western Nevada with the best chances and coverage
    expected along and east of US-395 and south of I-80. Ample
    moisture aloft (PWAT >0.85") and modest storm motions could
    produce areas of heavy rainfall and localized flash flooding,
    mainly for burn scar areas across E.Alpine, Mono, Douglas, 
    and S.Lyon. Gusty outflows could yield areas of blowing dust.

  - Farther north across E.Modoc and far N.Washoe counties, storm
    motions will be rather quick (20-25 knots of steering flow).
    This combined with some initially dry boundary layers could
    produce isolated dry strikes with a potential for strong
    outflows(>50 mph) which could exacerbate any new fire starts.

* Monday-Thursday:

 - Isolated to scattered storm coverage will be possible on Monday
   with the best chances (30-40%) largely remaining south of 
   US-50 across the Sierra and western Nevada. 

  -Storm chances will increase and track farther north Tuesday and
   Wednesday as moisture filters northward across the western
   periphery of a high pressure ridge. The best chances will 
   remain south of US-50 (40-60%) with 20% chances up to I-80. 

  -The increased moisture may allow for higher chances for areas 
   of heavy rain and localized flash flooding, particularly in 
   burn scar areas across portions of Alpine, Douglas, S.Lyon, and
   Mono counties. 

  -Moisture will begin to shift eastward on Thursday. Lingering
   shower and storm chances will remain across areas mainly south
   of US-50 once again. Overall, flash flooding threat will begin
   to wane as this moisture filters eastward. 


COOLING TREND WITH BREEZIER AND DRIER CONDITIONS: 

* Temperatures will turn the corner after midweek with a cooling
  trend expected into the weekend. Temperatures will return to 
  right around season averages next weekend with low to mid 90s 
  for W.Nevada and low 80s for Sierra valleys.

* A drier southwest flow associated with a shortwave trough will
  attempt to push in around the Thursday timeframe. As this
  shortwave nudges inland, it will decrease storm chances across
  the Sierra and Sierra Front, but isolated to scattered coverage
  will still be possible across Mono, Mineral, and into Pershing
  and Churchill counties. 

* This will also introduce drier conditions with enhanced
  southwest breezes after midweek. This may materialize into 
  elevated fire weather concerns, particularly in any actively 
  burning areas. Fuentes

&&

.AVIATION...

* Afternoon shower and thunderstorm chances will prevail across 
  the E.Sierra and far W.Nevada terminals today after 20z. 20-30% 
  chances across KTRK,KTVL,KRNO,KCXP,and KMEV with 35-40% chances 
  at KMMH. These storms will be capable of brief periods of 
  MVFR/IFR conditions with periods of heavy rainfall, small hail, 
  and frequent lightning at times. 

* Strong and gusty outflow winds are possible this afternoon which
  could send strong outflows across basin and range terminals
  including KLOL, KNFL, and KHTH. Outflows in excess of 45 kts 
  could result in sudden reductions to visibility due to areas of 
  blowing dust downwind of desert sinks and dry lake beds. 

* Daily afternoon shower/storm chances will continue into the first 
  half of next week with the best potential existing south of US-50. 
  Drier air will then attempt to move in for the second half of next 
  week. Fuentes

&&

.REV Watches/Warnings/Advisories...
NV...Heat Advisory until 8 PM PDT Tuesday NVZ004-005.

CA...None.

&&

$$