011 FXUS65 KVEF 091644 AAA AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 840 AM PST Sat Feb 9 2019 .SYNOPSIS...Two storm systems will bring increasing chances for precipitation and gusty winds to the area over the weekend. The heaviest snow is expected in the Sierra with the strongest winds over the western deserts. Temperatures will moderate somewhat over the weekend but remain below normal. Quiet conditions settle over the region Monday and Tuesday before more unsettled weather arrives mid week. && .UPDATE... Radar imagery showing enhancement of showers to the southwest of Las Vegas that will gradually push into the valley through 11 AM. With low dewpoints currently in the lower to mid 20s we could see some of these showers start at light snow, especially over the western and southern portions of the valley where elevations climb above 2800- 3000 feet. These showers are expected to late into the late morning with some clearing expected during the afternoon. && .AVIATION...For McCarran...Through the mid-morning, light and variable winds will prevail before sporadic light showers creep into the valley as well as a wind shift to the southwest. Winds are then expected to increase in the afternoon becoming 12-15 kts with gust potential peaking at 25 kts this afternoon. Light rain showers are possible through 11 AM with CIGs down to 5k feet at times. Improving conditions are expected this afternoon with clouds clearing. Winds are expected to decrease to around 10-12 kts this evening as CIGs decrease in coverage. For the rest of southern Nevada, northwest Arizona and southeast California...Breezy with a possible light shower or two is possible for valley sites by mid morning. KBIH briefly saw some snow this morning and another couple hours of light snow may be possible before clearing by the afternoon. KDAG may also see a brief shower this morning along with breezy southwest winds. && PREV DISCUSSION 409 AM PST Sat Feb 9 2019 .SHORT TERM...Today through Sunday Night. The first of two systems is ongoing across the western Sierra slopes struggling to reach the eastern slopes early this morning. MMH is reporting steady snowfall and KBIH has just begun reporting light snow as of 330AM. Latest hi-res depictions bring this area of moisture across the CWA throughout the day today but much like previous systems, will be very spotty in nature in regard to QPF. An added upslope component may bring a few inches to the Spring Mountains today but should be rather minor. As the shortwave translates across the Sierra, strong easterly 700 mb winds will result in mountain winds that increase throughout the day today and peak overnight tonight. Many hi-resolution models as well as the NBM really crank up wind potential after 00Z tonight and through 12Z Sunday morning. Considered upgrading to a High Wind Warning for the eastern slopes but held off for now, just upping the wording to 70 mph gusts in the advisory for now. The WSW was also moved up in time for the eastern Sierra as moderate to heavy snowfall may begin a bit earlier than previously thought. HREF and NBM both indicate moderate to heavy snowfall beginning between 06Z and 12Z so moved up the start time of the advisory to capture when additional impacts may begin. For Sunday, NBM seemed to be overdoing QPF generation associated with the frontal passage Sunday, producing 8-10 inches of snowfall in the higher elevations of Lincoln County. Other guidance such as SuperBlend, CONSALL, WPCGuide, and others were considerably lower. With the poor performance of the NBM on QPF over the last few events, tempered QPF down quite a bit. That being said, the tempered values still came close to advisory level snow for the Spring Mountains and Lincoln County mountains after 18Z tomorrow. Did not pull the trigger just yet on any additional WSW as I believe the trend of the HRRR and other hi-res will be decreasing in QPF generation as it has in the previous several events. Wind potential still looks well into advisory levels for much of the CWA. Saw no significant changes in expectations there so NPW was continued without change. .LONG TERM...Monday through Friday. This upcoming week is still shaping up to be fairly active with a succession of upper level Pacific low pressure systems tracking along a progressive northern stream and across the western states. Similar to previous discussions, there is a high degree of uncertainty in the extended forecast period due to significant differences among model solutions and continuous lacking of run-to- run consistency. There are two potential weak to moderate atmospheric river events being resolved this week the first on Wednesday and a second Friday/Saturday. The setup may lead to another significant/impactful snow in the eastern Sierra, where a couple feet of additional snow will be possible by the end of the week. Monday and Tuesday are expected to be fair as Sunday's weather system exits to the east, though below average temps are expected in its wake. Increasing southerly winds ahead of the next system along with increasing high clouds should quickly warm temperatures on Tuesday. The moisture associated with the first system has trended slower, now expected to reach the southwest on Wednesday. For Wednesday, the forecast is taking a drier trend, favoring the GFS solution, with the best forcing focused north of the CWA and the main fetch of moisture tracking further south into the Sonoran Desert areas. For the Mojave Desert and southern Great Basin zone valleys, QPF amounts are generally below 0.25", with the exception of the Owens Valley where spill over could lead higher amounts around 0.50". Mean pattern indicates a break on Thursday/Friday before another large, deep upper trough tracks along the west coast. This system may have a higher potential to bring a bout of rain to the Mojave Desert as it phases with a Rex low near the Hawaiian Islands and surges rich moisture into the region. Confidence is low on any specific details. Keep an eye on future updates, as this forecast will likely evolve over the next few days. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ UPDATE...Gorelow SYNOPSIS/SHORT TERM/AVIATION...TB3 LONG TERM....Boothe For more forecast information...see us on our webpage: http://weather.gov/lasvegas or follow us on Facebook and Twitter