Area Forecast Discussion
Issued by NWS Las Vegas, NV
Issued by NWS Las Vegas, NV
827 FXUS65 KVEF 142044 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 144 PM PDT Sat Sep 14 2024 .SYNOPSIS...A trough of low pressure approaching the northern Great Basin will bring an increase in south to southwest winds to the region tomorrow and Monday. Increasing moisture in the Colorado River Valley will also result in a slight chance of shower and thunderstorm activity over eastern Mohave County tomorrow and Monday. A second trough of low pressure will move across the area mid-week bringing cooler air that will lower temperatures to well below normal levels. && .DISCUSSION... A taste of fall is in store for the region this week as a series of low-pressure troughs move through the Great Basin. As the first trough approaches the area tonight and tomorrow, increasing south-to-southwest winds will spread across the region. Widespread winds of 20 to 25mph are expected Sunday afternoon over eastern California and northwest Arizona, resulting in the need for the Lake Wind Advisory that was issued earlier today. The latest high- res model runs also show increasing confidence of a belt of winds gusting over 40MPH developing Sunday evening across the Mojave Desert and spreading into southern Nevada and northwest Arizona on Monday. If this trend in guidance continues, wind advisories may be needed for those areas. Another concern is remnant moisture from Tropical Storm Ileana. The latest track from the NHC has the system hugging the eastern coast of the Gulf of California today, then dissipating by tomorrow evening. The GEFS and ECMWF ensemble both show the majority of the moisture from this system moving off to the east over Arizona and New Mexico. However, a modest increase in moisture in the Colorado River Valley is indicated in these models, as well as the NBM tomorrow and Monday. This uptick in moisture, coupled with increasing instability from the approaching trough, should be enough to cause a few showers and embedded thunderstorms tomorrow afternoon over Mohave County, generally east of Kingman. A few showers are also possible across northern Inyo, Lincoln, Nye, and Esmeralda counties on Monday as the base of the trough passes. As the first trough passes through the region on Monday, temperatures will fall to well below normal levels. High in Las Vegas on Monday will drop into the mid-80s, and lows will fall to near 60 on Tuesday morning. Some of the outlying areas of the valley will see lows down into the upper 50s. This colder air could also result in some precipitation in the Sierra and White Mountains above 9,000 feet to fall as snow late Monday and Monday night, but no more than an inch or two is expected. A second system will follow on the heels of the first trough and impact the area from Tuesday night through Thursday. This next trough will bring another round of breezy winds and increased precipitation chances across northern areas with it. Additionally, it will bring a reinforcing shot of cool air to the Desert Southwest, helping the cooler than normal temperatures stick around as we head into next weekend. && .AVIATION...For Harry Reid...Winds will turn to the southeast early this afternoon, and a few gusts of up to 25kts can be expected, mainly from 21Z through 02Z. Southwest winds are expected overnight, transitioning from the southeast to the southwest between 23Z and 02Z. Winds will return to the southeast to south by late Sunday morning, with gusts to 30kts possible during the afternoon. Skies will remain hazy today into Sunday as smoke from the Southern California wildfires continues to spread across the region. While surface visibilities are expected to stay above 6SM, slantwise visibilities may be reduced below that, especially in the Daggett and Beatty corridors. Otherwise, mainly clear skies are expected into Sunday afternoon. For the rest of southern Nevada, northwest Arizona and southeast California...Increasing south to southwest winds are expected across the region this afternoon and evening, with the strongest winds forecast in the Owens Valley and over the western Mojave Desert. Winds will diminish overnight, with most areas seeing speeds fall below 10kts. KDAG will be the exception, and westerly winds with gusts of up to 20kts will likely continue until close to sunrise. Gusty winds will redevelop on Sunday, with gusts of 20 to 20kts possible at most regional TAF sites. Skies will remain hazy today into Sunday across southern Nevada and eastern California as smoke from the Southern California wildfires continues to spread across the region. While surface visibilities are expected to remain above 6SM, slantwise visibilities may be reduced below that level. Otherwise, mainly clear skies are expected into Sunday afternoon. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ DISCUSSION/AVIATION...Planz For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter