Area Forecast Discussion
Issued by NWS Las Vegas, NV
Issued by NWS Las Vegas, NV
811 FXUS65 KVEF 120245 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 745 PM PDT Tue Jun 11 2024 .SYNOPSIS...Hot and dry conditions continue over the next few days. A slight decrease in temperatures is expected later this week as low pressure passes to the south of the ridge, but temperatures will remain above average. A more noticable cooldown and increased winds are possible next week with a change in the weather pattern. Uncertainty remains at this time regarding the intensity of the cooldown and winds. && UPDATE...Other than a few decaying clouds over Esmeralda County, skies were clear across the area this evening as high pressure continued to influence our local weather pattern. This afternoon`s high temperatures rose well above normal, and even at this hour temperatures in many locations were running about 5 degrees warmer than this time yesterday. No changes were made to the overnight forecast as clear skies and light winds are expected overnight, It will remain mild overnight into Wednesday with overnight lows expected to be a few degrees warmer than last night. An Excessive Heat Warning remains in effect through Wednesday evening as little relief overnight will compound the effects of the hot afternoon. -Nickerson- && .PREVIOUS DISCUSSION...1237 PM PDT Tue Jun 11 2024. .SHORT TERM...Tonight through Saturday The primary weather concern in the short term is heat. A 500 mb ridge with maximum heights around 595 dm is in place over the southwest United States as a low pressure system spins off the Southern California coast. The result is above average temperatures at the surface and Moderate (Level 2) to Major (Level 3) HeatRisk through Wednesday within the forecast area. Therefore, the Excessive Heat Warning for sections of Inyo, Mohave, southern Nye, and Clark County including Las Vegas will remain in effect from now into Wednesday evening. This level of heat will affect anyone without effective cooling and hydration and extra caution is advised. The previously mentioned low pressure system will cut under the ridge and move east through southern California and Arizona on Thursday and Friday. Falling heights aloft should help bring temperatures down a few degrees on Thursday, but highs will still be 5 to 10 degrees above normal for this time of year. Afterwards, the warming trend continues on Friday and Saturday as the shortwave exits to the east and pressure builds again. Southerly to southwesterly winds aloft should bring breezy surface winds, especially along high terrain. Lastly, moisture associated with the low will increase PWAT values in northwest Arizona on Thursday to over 100 percent of normal for this time of year, or .4 to .6 inches. However, most of the moisture with the system appears elevated as seen on current satellite imagery. Forecast soundings also show an inverted V pattern with most of the moisture aloft and dyer air near the surface. A few isolated rain showers may form on Thursday, but most precipitation may evaporate before reaching the ground given RH values in the teens to single digits. Lightning is not a concern in northwest Arizona given a lack of atmospheric instability over the area with the greatest moisture. However, a few thunderstorms may develop in Inyo County over the Sierra crest. Although there is less moisture, there is better instability and lift over the mountains. .LONG TERM...Early Next Week. The weather pattern is expected to transition late this weekend and early next week as we lose the influence of the ridge. Low confidence in how everything sets up synoptically though as there are significant differences in long range model camps on how an incoming trough will interact with the weakening ridge. Many models have some flavor of the trough digging south into the region from the Pacific Northwest, however there are differences in how deep the trough digs and how quickly it will continue its eastward progression. Increasing confidence there will be some type of cooling trend but unsure what temperatures will look like. NBM ensemble high temperature spread for that time period is very large with anything from near normal to well below normal, especially early next week. Depending on the exact setup of the trough, winds could increase as well. Currently, there are some ensemble members of 40 MPH or higher gusts on area meteograms for Sunday into early next week, so the chance for impactful winds is non-zero. More notable, with dry conditions and the potential for increasing winds, fire danger would increase. SPC fire weather outlooks highlight a 40% potential for increased fire danger on Saturday and Sunday in portions of southern Nevada into western Arizona. Will need to monitor wind and fuel trends in case fire danger rapidly increases. && .AVIATION...For Harry Reid...Expecting a predominantly light and diurnal wind pattern through the TAF period, with east/southeast winds at times this afternoon and south/southwest at night. Speeds generally in the 5-8 knot range, with only a slight chance of wind gusts exceeding 10+ knots this afternoon. Clear skies. For the rest of southern Nevada, northwest Arizona and southeast California...Light and diurnal winds anticipated at all of the area TAF sites through tonight. Sustained winds should peak around 8-12 knots this afternoon and evening, with occasional gusts up to 16 knots possible. Mostly clear skies as just a few mid-level and high clouds linger over the lower Colorado River Valley and KBIH. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ SHORT TERM...Meltzer LONG TERM...Nickerson AVIATION...Gorelow For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter