Area Forecast Discussion
Issued by NWS Las Vegas, NV
Issued by NWS Las Vegas, NV
170 FXUS65 KVEF 250411 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 910 AM PDT Wed Apr 24 2024 .SYNOPSIS...Breezy conditions are expected through the weekend along with a gradual cooling trend as two low pressure systems move through the region. The strongest winds will be in western San Bernardino County, and a Wind Advisory has been issued for that area. By Friday and Saturday, temperatures will fall below late April normals, and there will be a chance of showers mainly along and north of Interstate 40. Warmer and dryer conditions return next week. && .UPDATE...Breezy southwest winds across the area will continue overnight before somewhat diminishing in the early-morning hours... and then returning Thursday afternoon. West-southwest winds will increase over the next few hours in western San Bernardino County to around 40 mph. As such, a Wind Advisory is in effect. No changes made to the forecast this evening, as it looks to be in good shape. && .PREVIOUS DISCUSSION...1136 AM PDT Wed Apr 24 2024/ .SHORT TERM...through Friday night. A pair of low pressure systems will be the main drivers for weather over the next few days. The first system is currently off the California Coast and will move through the Southwest United States later today and tomorrow, followed shortly after by a system dipping south from the Pacific Northwest tomorrow and Friday. There will be three notable impacts from these systems: increased winds, chances for precipitation, and cooler temperatures. The development of a low level jet associated with the troughs will lead to increased southwesterly surface winds for most of the forecast area. A Wind Advisory will go into effect at 5 PM PDT for western San Bernardino County, where gusts up to 55 mph are expected. The Advisory will remain in effect through Friday, although there may be occasional periods of weaker winds. The strongest winds are expected to arrive on Friday as the deeper trough drops in from the north. An increase in winds in the Morongo Basin and Mojave National Preserve may necessitate the expansion of the Wind Advisory into those areas by Friday. As of now, the NBM gives those areas a 70 to 90 percent chance of reaching Wind Advisory level gusts on Friday. Gusty winds and reduced visibility due to blowing dust may make for difficult traveling conditions on highways through San Bernardino County, including Interstate 15 and Interstate 40. Satellite imagery as of 11 AM PDT shows the development of a cumulus field over Esmeralda County and far northern Inyo County, some of which have started to produce lightning. CAMs indicate an increase in instability this afternoon as the trough approaches the area. Instability along with PWATs around 180 percent of normal point to further development of showers and thunderstorms in that area through the afternoon, along with some snow showers in high elevations of the Sierra and White Mountains. POPs follow the movement of the low and shift east into Nye and Lincoln counties tomorrow. The day with the most widespread precipitation potential is Friday as the second low moves in from the north, temperatures cool aloft, and PWATs rise to 150 percent of normal or greater for most of the forecast area. POPs north of Interstate 40 have increased since the previous forecast package, particularly over areas of high terrain. Las Vegas has a 72 percent chance of receiving at least 0.01 inch of rain on Friday. The highest precipitation totals between the three days should be in the southern Great Basin, where up to half an inch of rain is possible in Lincoln County. An inch or two of snow is also possible above 7000 feet in elevation, which includes the tops of the Spring Mountains and Sheep Range. However, impacts are not expected from this snowfall. Temperatures are also expected to continue their downward trend as heights fall aloft. Highs should be near average tomorrow and below average by Friday. For Las Vegas, this means highs on Friday in the low 70s. .LONG TERM...Saturday through Wednesday. The base of the trough will push through the region Saturday leaving a few lingering showers over the far eastern portions of Lincoln and Mohave counties. The general flow will be from the northwest which will keep some of the cooler temperatures in place. Highs Saturday are expected to be about 6-9 degrees below normal. Heights will begin to rise Sunday as a weak ridge moves into the western US, resulting in warming temperatures through Tuesday. There are indications that the unsettled pattern will continue through the end of the week as another trough digs out of the Gulf of Alaska, resulting in another cooling trend Wednesday and beyond; however, confidence overall remains low at this time. && .AVIATION...For Harry Reid...Breezy south or southwest winds will prevail through the TAF period with winds easing in intensity late tonight through early tomorrow afternoon before returning again. Wind gusts during the breezy periods will exceed 20 knots at times. Otherwise, mostly clear skies are expected today with a few mid and high clouds late tonight that will persist into tomorrow afternoon. For the rest of southern Nevada, northwest Arizona and southeast California...Across the Mojave Desert and Colorado River Valley, breezy southwest or westerly winds are favored through the TAF period, with the strongest winds expected near KDAG where gusts to 35 knots or higher are likely by this evening. Skies will be mostly clear with just some passing mid and high clouds. Further north, shower and thunderstorm activity is expected in the Sierra and near KBIH with CIGs falling to 5-8kft AGL and locally Gusty surface winds. Shower activity may persist into the night before tapering off prior to sunrise Thursday. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ UPDATE...Varian SHORT TERM...Meltzer LONG TERM...Gorelow AVIATION...Outler For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter