FXUS65 KVEF 201148

AFDVEF



Area Forecast Discussion

National Weather Service Las Vegas NV

448 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 12Z Forecast Package...Winds

will generally follow diurnal patterns, similar to previous days.

Variable winds this morning will veer and settle out of the east 

and southeast this afternoon, before shifting to the southwest 

this evening. Sustained speeds are expected to remain 10KT or 

less, with minimal chances for higher gusts. VFR conditions 

prevail through the forecast period, with increasing mid-level and

high clouds, especially this evening onward. Temperatures today 

will exceed 100F between 18Z-05Z, with a high of 108F around 00Z.





For the rest of southern Nevada, northwest Arizona and southeast

California...For the 12Z Forecast Package...Winds across the

region will generally follow diurnal patterns, with speeds 

remaining around 10KT or less through the forecast period. 

Exceptions are across the Owens Valley, where gusty up-valley 

winds to 20-25KT are expected to develop this afternoon, and 

across the western Mojave, where a period of elevated and 

intermittently gusty westerly winds is expected this evening into 

tonight. Otherwise, VFR conditions prevail with increasing mid and

high clouds through tonight.



&&



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

any significant weather or impacts according to standard operating

procedures.



&&



$$DISCUSSION...Stessman

AVIATION...Phillipson



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