Area Forecast Discussion
Issued by NWS Las Vegas, NV

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000 FXUS65 KVEF 141113 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 313 AM PST Thu Dec 14 2017 .SYNOPSIS....Breezy to windy conditions are expected across the area today with continued dry and mild weather. Lighter winds but cooler temperatures are forecast for Friday before another cold front brings more wind to the area Saturday. && .SHORT TERM...Today through Saturday. A sharp upper level shortwave is sliding south along the eastern edge of the forecast area. Surface pressure gradients are strengthening and we have seen a 16 mb difference between Reno and Las vegas and 13 mb difference between Ely and Needles. These gradient numbers are impressive but have not translated to wind speed strength...except in a couple of locations. The surface cold front associated with the upper level disturbance has reached into the northern portions of the Las Vegas Valley as of 2 am this morning. Gusts have been up to 30 mph so far. A Wind Advisory went into affect at 2 am and extends through this afternoon for areas south of Las Vegas. In addition, Red Flag conditions are expected along the Colorado River Valley today as strong wind gusts couple with low humidity and very dry conditions to increase fire danger. Temperatures are expected to be cooler today overall except in isolated situations such as Death Valley National Park where compressional heating due to elevated northeast winds will warm temperatures around 10 degrees over Tuesday. Advisory level winds and red flag conditions will end by evening time as the system moves away and is replaced by shortwave ridging. Light winds are forecast overnight and Friday except for lingering north winds in the Colorado River Valley. Cooler temperatures in the wake of the front for Friday will linger into Saturday as well. The next Pacific trough reaches the Pacific NW coast Friday afternoon and splits in two with he southern energy moving south along the West Coast and becomes a closed low west of the southern California coastline. The northern energy rolls into the Intermountain Region and draws a cold front south through our area on Saturday. This will bring another round of gusty northerly winds to the region late Saturday. For the most part, mostly clear conditions can be expected today through Saturday however, a thick batch of high clouds will move over the area Friday night which may help in keeping low temperatures warmer on Saturday morning. .LONG TERM...Sunday through Thursday. Models are in decent agreement that by Sunday morning a split shortwave will be pushing south & east of the area, leaving gusty north winds in its wake and cooler (closer to normal) temperatures. It`s still unclear on whether northerly winds will reach advisory levels, but the most likely location for that is down the Colorado River Valley. Things will calm and warm Monday and Tuesday as ridging tries to build back in. However, that ridging will build a bit further west over the eastern Pacific instead of the western US. This will keep the door open for additional, deeper waves to ride down the eastern edge of the ridge. Confidence is low in the details right now, but the first of those waves may approach the region next Wednesday, increasing southwesterly flow (and winds) across the area. This system appears to be relatively dry, but could squeeze out a little precipitation over the Sierra/southern Great Basin late next week. Depending on the track and depth of the systems late next week, they could usher in the coldest air of the season, as well as periods of strong winds, and perhaps even some precipitation (again, for the moment things continue to look mostly dry). && .AVIATION...For McCarran...Gusty north winds will continue into the afternoon then begin decreasing in the late afternoon and evening. Wind speeds will generally be in the 12-25 kt range. Expect lighter winds on Friday before another front brings gusty northerly winds back to the terminal on Saturday. For the rest of southern Nevada, northwest Arizona and southeast California...Gusty north winds can be expected this morning with decreasing wind speeds through the afternoon. Winds will generally be in the 12-25 kt range through Thursday afternoon. The strongest winds will develop down the Colorado River Valley with gusts around 40 kts. Some enhanced northerly winds are also possible over eastern Lincoln County where gusts may approach 30 mph. Other than a few high clouds, skies will remain mostly clear. && .FIRE WEATHER...A cold front will produce more widespread stronger north winds today along the Colorado River Valley with gusts over 35 mph expected. North winds will linger through the weekend as a series of weak disturbances pass across the region. A Red Flag Warning is in effect today for the Colorado River Valley due to these strong winds, low humidity and dry conditions. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ Short term/Aviation...Salmen Long term...Wolcott For more forecast information...see us on our webpage: http://weather.gov/lasvegas or follow us on Facebook and Twitter

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