Area Forecast Discussion
Issued by NWS Las Vegas, NV
Issued by NWS Las Vegas, NV
514 FXUS65 KVEF 202230 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 330 PM PDT Thu Jun 20 2024 .SYNOPSIS...Increasing temperatures and the first influx of moisture associated with the North American Monsoon and the remnants of Tropical Depression Alberto are expected in the coming days. Temperatures will climb to around 5-10 degrees above normal over the weekend while tropical moisture will increase over western Arizona, southern Nevada and eastern California Friday through early next week. This moisture will lead to an increase in shower and thunderstorm chances, while the hottest temperatures have shifted to next week when decreasing moisture is forecast. && .DISCUSSION...through next Thursday. Current infrared and water vapor satellite imagery show an upper- level trough slowly moving inland along the West Coast. This trough will continue to move inland before lifting northeast through southern Nevada into southwestern Utah tomorrow. Isolated showers and thunderstorms will be possible across northern Mohave County as this trough lifts through the region tomorrow afternoon. While this trough is moving through the area, Tropical Depression Alberto will have traversed Mexico and entered the Gulf of California. Remnant moisture from Alberto will begin to push into Mohave County as early as tomorrow, spilling into Clark and eastern San Bernardino counties over the weekend. As you would expect, increased precipitation chances will accompany this influx of moisture over the weekend. The best precipitation chances will be limited to Mohave County on Saturday, with more widespread precipitation chances (20% to 30%) for areas south and east of the I- 15 corridor on Sunday afternoon. Confidence regarding exact precipitation amounts remains low at this time due to uncertainty regarding where storms will develop. Additionally, there is a chance that we will see increased cloud cover associated with this anomalous moisture, which will limit daytime heating. Without a source of synoptic lift, such as a trough, daytime heating would be the primary source of lift for convective initiation and if daytime heating is limited then convection would also be limited. Once the aforementioned trough clears out of the area, a ridge of high pressure will begin to develop over the Southwestern US over the weekend. This will allow for temperatures to continue to heat up to around 5 to 10 degrees above normal over the weekend. The remnant moisture from Alberto will act as a damper, preventing temperatures from really taking off until early next week. Widespread Moderate HeatRisk is expected over the weekend, with pockets of Major HeatRisk in Death Valley, Amargosa Valley, and portions of the Las Vegas Valley. HeatRisk will increase early next week as temperatures heat up another few degrees, yielding Major to Extreme HeatRisk in the Colorado River Valley, Las Vegas Valley, Amargosa Valley, and Death Valley. An incoming trough will erode at the overhead ridge around mid-to- late week and will eventually scour out any lingering anomalous moisture from Alberto. However, there remains much uncertainty regarding the evolution of this system. && .AVIATION...For Harry Reid...Light easterly breezes will gradually veer to the south throughout the afternoon. Strongest winds expected in the late afternoon (roughly 23z), with peak gusts around 18-22 knots from a 160-210 direction. By sunset, wind speeds subside and remain light through the night. Clear skies persist. For the rest of southern Nevada, northwest Arizona and southeast California...South-southeast breezes gradually develop this afternoon and evening at most TAF sites, with peak gusts around 20- 25 knots. The exception will be KDAG, where west-southwest winds prevail. Clear skies at most locations, though KBIH will see FEW-SCT clouds at or above 12kft. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ DISCUSSION...Stessman AVIATION...Woods For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter