Area Forecast Discussion
Issued by NWS Las Vegas, NV
Issued by NWS Las Vegas, NV
257 FXUS65 KVEF 160750 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 1250 AM PDT Tue Jul 16 2024 .SYNOPSIS...Storm coverage will become more isolated today with fairly weak storms anticipated mainly across Northwest Arizona through Wednesday. Storm chances will gradually build back westward Thursday through the weekend as the Four Corners high migrates west. Temperatures will also heat up and climb well above normal over the weekend. && .SHORT TERM...through Wednesday. A few very light showers persist this evening across southern Mohave County associated with mid level moisture trapped within the Four Corners High circulation. Convection today will trend more sparse owing to some drier mid-level air working in from the west and the presence of a subsidence inversion near 500mb developing over the area. This warm layer will still permit some afternoon cumulus build ups over the higher terrain, but will likely stifle most updrafts outside of northwest Arizona where somewhat deeper moisture exists. Meanwhile, warm temperatures will prevail with somewhat greater surface heating than past days expected thanks to reduced convective coverage. .LONG TERM...Thursday through next Tuesday. The high pressure ridge will continue to retrograde back to the west, amplifying as it goes. As this ridge moves back towards us, we will see the upper-level flow become more southerly, allowing for additional moisture to creep into the area. As such, we see precipitation chances increase across the eastern portions of our forecast area on Thursday and Friday. By the weekend, both the GEFS and ECMWF ensemble means are in good agreement that the ridge will be centered over where Nevada, Utah, and Arizona meet (i.e., directly overhead). With the ridge moving back overhead and settling above us, we will see temperatures increase a little each day as we head into the weekend. By Saturday we will see the reintroduction of Major HeatRisk in the lower elevations, accompanied by patchy Extreme HeatRisk in places. Major and Extreme HeatRisk will become more expansive on Sunday as the ridge remains positioned overhead. These hotter than normal temperatures will continue to help fuel afternoon convection as moisture remains trapped under the ridge. With the moisture around, overnight lows will remain elevated and conditions may feel more humid than our typical heat events. Forecast confidence decreases as we head into next week due to uncertainty in the location of the ridge and potential for monsoonal influences to impact the area. && .AVIATION...For Harry Reid...Winds will largely favor typical diurnal trends today, with variable or northeast winds this morning, then becoming southerly during the afternoon. Speeds through the afternoon should generally remain less than 10kts, although occasional gusts to 15kts are possible once the winds turn to the south. Southwest winds will develop by sunset with speeds of 10 to 12kts possible through 07Z before decreasing. Isolated areas of convection are possible over the higher terrain surrounding the valley this afternoon. While no storms are expected to impact the terminal area directly, outflow winds from nearby storms can not be ruled out during the late afternoon or early evening. VFR conditions will prevail with only a FEW clouds AOA 12kft AGL forecast. For the rest of southern Nevada, northwest Arizona and southeast California...Isolated thunderstorms are again possible today, but most of the activity should be confined to the higher terrain of southern Nevada and northwest Arizona. Any of the storms will be capable of producing lightning, brief periods of heavy rainfall, CIGs less than 8kft that could obscure areas of higher terrain, and sudden gusty outflow winds. Away from storms, south-to-west winds 8kts to 12kts with occasional gusts to 15kts, along with VFR conditions with only a FEW clouds AOA 12kft to 15kft AGL are expected at the regional TAF sites. The threat of isolated thunderstorms continues on Wednesday, mainly across northwest Arizona. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ SHORT TERM...Outler LONG TERM...Stessman AVIATION...Planz For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter