FXUS65 KVEF 200923

AFDVEF



Area Forecast Discussion

National Weather Service Las Vegas NV

223 AM PDT Wed Aug 20 2025



.KEY MESSAGES...



* Extreme Heat Warnings and Heat Advisories will go into effect

  this morning, continuing through Saturday as hotter than normal

  temperatures stick around through the end of the week.



* Monsoonal moisture will return to the Southwestern US, bringing

  increased chances for afternoon showers and thunderstorms as we

  head into the weekend. Lightning, strong outflow winds, and

  heavy rain capable of resulting flash flooding will be potential

  hazards with these storms. 



&&



.DISCUSSION...through next Wednesday.



Temperatures will continue to heat up through the end of the work 

week as we find ourselves under a ridge of high pressure centered 

over the Four Corners region. As we continue to heat up, we will see 

high temperatures top out around 4 to 8 degrees above normal by the 

end of the week. In addition to afternoon temperatures being hotter 

than normal, there will be little relief in the form of overnight 

low temperatures as those will be around 5 to 12 degrees above 

normal later this week. These warmer than normal overnight 

temperatures combined with hotter than normal afternoon high 

temperatures will quickly drive HeatRisk up across southern Nevada, 

northwestern Arizona, and southeastern California. Furthermore, with 

the ridge centered over the Four Corners, we will see monsoonal 

moisture increase across the region. This will make things feel 

muggier than normal, especially given how dry this summer has been.



Speaking of the return of monsoonal moisture, we will begin to see 

chances for showers and thunderstorms creep into the eastern portions 

of our forecast area on Thursday afternoon. Chances for afternoon 

convection will become more widespread on Friday and Saturday with 

precipitation chances hanging around into next week. Strong outflow 

winds, localized heavy rain capable of resulting in flash flooding, 

and lightning will be threats with any storms that develop during 

the second half of the week. The monsoonal moisture will stick 

around into next week, recirculating beneath the ridge. Despite the 

presence of anomalous moisture, confidence in anything beyond 

shallow terrain based convection is low due to the subsidence 

beneath the ridge. However, mesoscale phenomena such as an MCV or 

sufficiently strong outflow winds could help with additional 

convective development.



&&



.AVIATION...For Harry Reid...For the 06Z Forecast Package...Quiet 

weather is expected overnight with the typical southwesterly winds. 

Light winds early Wednesday morning should become easterly late in 

the morning, remaining less than 10 knots outside of any sporadic 

gusts as temperatures heat up. Winds should go back around to 

southwesterly around sunset. High clouds will be increasing, but no 

clouds expected at or below 10K feet. Temperature rising above 100F 

around 19Z, peaking around 108F, then falling below 100F around 04Z.



For the rest of southern Nevada, northwest Arizona and southeast 

California...For the 06Z Forecast Package...Generally quiet weather 

is expected through Wednesday evening, with wind gusts of 20 knots 

or less following typical day/night directional patterns. High 

clouds will increase from south to north, but no clouds expected at 

or below 12K feet MSL.

&&



.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report

any significant weather or impacts according to standard operating

procedures.



&&



$$



DISCUSSION...Stessman

AVIATION...Morgan



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