121 FXUS65 KVEF 062230 AFDVEFArea Forecast Discussion National Weather Service Las Vegas NV 330 PM PDT Sat Sep 6 2025
.KEY MESSAGES...
* Monsoonal moisture will remain in place through tomorrow, promoting afternoon shower and thunderstorm activity.
* A drying trend is expected the first half of the week as flow becomes more westerly. Relatively cooler temperatures will also overspread the region by mid week.
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.DISCUSSION...Through next Friday. Moisture remains in place today over the southeastern portions of the CWA. PWATs up to 1.20" are currently stretching northward through Mohave County and as far west as eastern Clark County. Values continue to drop further west as some drier air has worked into the western portions of the CWA. The main focus for thunderstorms this afternoon will be over Mohave County and possibly as far west as eastern Clark and eastern San Bernardino counties. Due to the lack of any significant forcing, storms today will be more terrain based and generally more isolated than we have seen over the past few days. With plenty of deep moisture in place, especially over Mohave County, flash flooding will again be a concern, but isolated severe storms are also not out of the question as DCAPEs are running about 1300-1600 j/kg. Any storms that do form this afternoon will die off quickly after sunset and we are not expecting to see a repeat performance of the overnight convection we have seen the past two days.
Moisture will continue to decrease Sunday, but there will still be enough instability for isolated thunderstorms over Mohave County and possibly as far west as the Colorado River and eastern San Bernardino, but those probabilities will remain less than 15%.
Ensembles display rather high confidence in the development of a large upper trough off the California coast. This will push any remaining moisture east of the region, resulting in drier conditions areawide by Monday. With lower heights, we can also expect to see temperatures around 5-10 degrees below seasonal normals by midweek. This means highs in the low 90s for Las Vegas. The drier air will also bring more relief overnight with cool morning lows, including temperatures in the low 70s in Las Vegas by midweek.
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.AVIATION...For Harry Reid...For the 00Z Forecast Package...Isolated thunderstorms this afternoon will quickly dissipate after sunset with mainly clear skies overnight. It is possible that some gusty outflow winds will remain through 02z with gusts to 30 knots, but the probability of a TS at the terminal is less than 10 percent. Outside of convective influences, winds will remain around 8KT or less, and may be somewhat variable through the forecast period. VFR conditions will prevail, with temperatures remaining under 100 degrees. Isolated thunderstorms will be possible Sunday, but most are expected to remain east of the terminal.
For the rest of southern Nevada, northwest Arizona and southeast California...For the 00Z Forecast Package...Thunderstorm coverage is expected to be much less today as drier air begins to work into the region from the west. Thunderstorms will still be possible into this evening over Mohave County and eastern Clark County, with lesser chances across eastern San Bernardino County. Any storms will weaken and diminish after sunset, with winds remaining around 10KT or less outside of convective influences. Exceptions will be across the Owens and Lower Colorado River Valleys, where gusty up-valley winds are expected through the afternoon. VFR conditions will prevail away from storms. Isolated thunderstorms are expected again Sunday with the greatest coverage over Mohave County and possibly as far west as the Las Vegas Valley.
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.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures.
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DISCUSSION...Gorelow AVIATION...Gorelow
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NWS VEF Office Area Forecast Discussion