![National Oceanic and Atmospheric Administration](/build/images/header/noaa.d87e0251.png)
![National Weather Service](/build/images/header/nws.4e6585d8.png)
![United States Department of Commerce](/build/images/header/doc.b38ba91a.png)
Area Forecast Discussion
Issued by NWS Las Vegas, NV
Issued by NWS Las Vegas, NV
043 FXUS65 KVEF 130928 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 228 AM PDT Sat Jul 13 2024 .SYNOPSIS...A monsoonal pattern is in place and thunderstorms are possible across most of the area today and tomorrow. These storms may bring gusty winds, frequent lightning, and heavy rainfall. Thunderstorms become more isolated next week as drier air filters in from the west. Additional moisture and cloud cover will help moderate temperatures but afternoon highs will still remain several degrees above average. && .SHORT TERM...through the weekend. The position of a strong 500 mb high centered over the Four Corners brings southeasterly to southerly winds aloft, a pattern favorable for monsoonal moisture advection into Arizona, Nevada, and eastern California. Increased moisture on sounding profiles supports CAPE between 500 and 1000 J/kg with the greatest values around the Nevada, Arizona, and California tripoint. PWAT values rise to the 1 inch to 1.4 inch range in Mohave, Clark, and San Bernardino Counties, and the .7 to 1 inch range in areas further to the north. This moisture is 120 to 150 percent of normal for this time of year. However, a closer look at forecast soundings indicates persistent dry air at the surface and most of the moisture aloft. Cloud bases of around 10 kft or higher and dry low levels yielding 2000 J/kg DCAPE mean strong outflow winds are a threat with any storms that form this weekend, as seen with storms that already occurred over the past two days. Blowing dust along outflow boundaries is also possible, which will reduce visibility and create dangerous travel conditions. HREF shows a 30 to 60 percent chance of gusts reaching at least 40 mph with storms this afternoon. A secondary threat for Mohave County is isolated and brief heavy rainfall which could cause flash flooding. WPC placed a Marginal (5 percent) risk for excessive rainfall for both today and tomorrow in eastern Mohave County. Rainfall totals up to .3 inch are possible under the strongest cores, particularly over high terrain where orographic lift is greatest. Lastly, dry thunderstorms and cured fuels on the ground bring increased fire weather concerns in the eastern Sierra and Owens Valley where a Red Flag Warning is in place. See the Fire Weather section for more details. Storm activity today and tomorrow will begin in the late morning and early afternoon, increasing in coverage through the afternoon, then tapering off overnight. Relatively lower temperatures compared to earlier this week bring HeatRisk down into the Moderate (Level 2) for most areas this weekend. Afternoon highs remain several degrees above average. .LONG TERM...Monday through Friday. A ridge of high pressure will continue across the desert southwest next week. The ridge will be positioned in a place conducive too push a little moisture northward, but there isn`t a favorable dynamic situation to have a strong, persistent push. The monsoonal moisture we do have in place will linger into the beginning of the work week, mainly over southern portions of the CWA. The chance of precipitation will be greatest Monday across eastern Mohave County and the southern Great Basin. Drier conditions can be expected each day through the week. While temps will remain above normal for much of the area, conditions will be a bit cooler than we have experienced over the past week. && .AVIATION...For Harry Reid...Light winds this morning should turn more easterly by late morning with speeds remaining below 10kts. Convection is expected to develop over the higher terrain surrounding the Las Vegas Valley after 19Z, and there is a 40% to 50% chance of one of the storms moving off the terrain and directly impacting the field, with 23Z to 03Z being the time of the highest chances. If a storm does not directly affect the field, gusty outflow winds from nearby storms have a high (greater than 70%) probability of causing impacts in the terminal area. Any thunderstorms could bring lightning, brief rain, and sudden gusty winds. Outside of convective activity, southwest winds can be expected into the early evening. Model guidance continues to show a brief period of northwest winds after sunset, but winds should return back to the southwest around midnight. Additional thunderstorm activity is possible on Sunday, although coverage is expected to be less than what occurs today. For the rest of southern Nevada, northwest Arizona and southeast California...Scattered areas of convection are expected to develop across most of the region this afternoon and evening, and any storms will be capable of producing lightning, brief rain, CIGs to 10kft, and sudden gusty outflow winds. Guidance also indicates that storms near KDAG this afternoon have a greater than 60% chance of generating gusty outflow winds that could spread northward into the Owens Valley during the late afternoon and evening, possibly reaching KBIH between 00Z and 02Z. Away from areas of convection, south to west winds around 12kts and occasional gusts to 20kts can be expected. The thunderstorm activity should diminish after sunset, and winds should fall below 10kts across the region overnight. Additional thunderstorm activity is possible on Sunday, although coverage should be less than what is seen today and be mainly over southern Nevada and northwest Arizona. && .FIRE WEATHER...Thunderstorms will increase in coverage across much of the region today and tomorrow as improved monsoon moisture works its way into the area. However, high storm bases and dry air near the surface mean any storms that form may produce gusty and erratic outflow winds and little precipitation at the surface. Dry thunderstorms are particularly a concern across western Inyo County where a Red Flag Warning remains in effect for the Sierra and Owens Valley. Additional dry thunderstorms also cannot be ruled out in sections of Esmeralda, Nye, and Lincoln Counties. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ SHORT TERM...Meltzer LONG TERM...Berc AVIATION...Planz For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter