Area Forecast Discussion
Issued by NWS Las Vegas, NV
Issued by NWS Las Vegas, NV
194 FXUS65 KVEF 191953 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 1252 PM PDT Wed Jun 19 2024 .SYNOPSIS...First sign of the North American Monsoon expected in the coming days. Tropical moisture will increase over eastern Arizona Thursday, then continue west into western Arizona, southern Nevada and eastern California Friday through early next week. This will bring an increase in shower and thunderstorm chances, while high temperatures slightly moderate with the onset of higher humidity. && .DISCUSSION...Through next Wednesday. First taste of the North American Monsoon set to arrive in the coming days as guidance continues to get more `bullish` on moisture advection into the region. There is now Tropical Storm Alberto in the southwest Gulf of Mexico, which is progged to move inland into mainland Mexico tomorrow. The remnants of Alberto will then continue to move west into the eastern Pacific along the southern periphery of a strong subtropical ridge expanding westward over the Desert Southwest. Moisture presently over west Texas, New Mexico and northern Mexico will advect westward underneath the ridge on east-southeast winds, arriving into eastern Arizona Thursday. That moisture continues to move west into western Arizona, southern Nevada and eastern California Friday into early next week. As the remnants from Alberto cross into the eastern Pacific and southern Gulf of California it could induce a gulf surge transporting additional moisture into the lower Colorado River Valley. Both the GEFS and EPS both indicate precipitable water values peaking over the weekend into early next week with values ranging from 1` to 1.5` from around Las Vegas/Mesquite south through western Arizona and eastern California. Therefore, the chance for showers and thunderstorms has continued to increase, and expand further west from Friday into early next week. Initial storm conditions will likely support gusty winds and dry lightning potential, as moisture deepens storms should transition to seeing more rain reach the ground. For the past two days had some concern for `excessively hot` temperatures occurring over this weekend as massive ridge currently over the eastern/central US migrated back west, repositioning itself over the Desert Southwest. Now with more moisture expected to advect into the region, NBM temperatures have moderated some. Yesterday, NBM probabilities of Las Vegas high temperatures 110+ were 60%-70%, today that has dropped to around 40%. In actual numbers, both Saturday and Sunday highs are now 2-3 degrees lower than yesterday. Therefore, not as many pockets of `Major` HeatRisk expected. But, again that heat will be offset by higher humidity values. && .AVIATION...For Harry Reid...Winds will follow a typical diurnal pattern for the remainder of today and tomorrow. Northeast to east winds will continue through the mid-afternoon before turning to the south-southwest by evening. Prior to the change to the southwest, speeds are expected to remain around 8 knots, although an occasional gust to 15kts can not be ruled out. After the southwest shift, speeds will increase to 10 to 12 knots with a few gusts to 18kts possible through sunset. Light and variable winds will return for tonight and Thursday morning. Skies will remain mainly clear through the TAF period. For the rest of southern Nevada, northwest Arizona and southeast California...Winds will follow a typical diurnal pattern through Thursday with light and, at times, variable winds overnight and breezy conditions in the afternoon and early evening. Occasional gusts to 20kts are possible across the western Mojave Desert and in the Colorado River Valley this afternoon, while gusts elsewhere will be limited. Besides a few clouds around 15kft AGL in the Owens Valley and along the Sierra, mainly clear skies will be seen across the region. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ DISCUSSION...Pierce AVIATION...Planz For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter