Las Vegas forecast discussion

Discussion

Through the Middle of Next Week.

Through the overnight, gusty northeast winds were reports across portions of the area at times. The strongest winds were in the terrain with gusts over 40 MPH reported as higher elevations intercepted a 50KT+ 850-700mb jet. This lower level jet associated with a low pressure system sitting over southern California will remain draped over southern portions of the region through rest of tonight before slowly shifting south and weakening this morning. While gusts are fairly isolated at the moment, expecting a quick uptick in the valleys early this morning as better mixing occurs with sunrise as well as an area of better vorticity advection on the backside of the low. A Wind Advisory remains in effect through 10AM this morning which looks good as additional minor wind impacts are possible with the uptick in winds after sunrise. Winds will diminish this afternoon as the low shifts south and weakens. Widespread gusts 20-30 MPH are expected this afternoon, then gusts under 20 MPH are expected through at least Monday. After a brief warm up to near normal today, temperatures drop a few degrees back to slightly below normal levels for the weekend.

Continuing to watch the potential for weather impacts around midweek as a deep West Coast trough impacts the region. Strong forcing will be associated with this deepening low, which some models have closing off as it moves into central or southern California. This forcing will interact with an uptick in moisture that advects into the region from distant Tropical Storm Simon ahead of the trough. Cluster analysis shows significant variation in how quickly the trough moves into the region as well as how deep it will be once it does so. In addition, models continue to advertise differing solutions on how an IVT plume sets up somewhere over southern Nevada or western Arizona. All that to say- there is significant uncertainty in the forecast details and potential impacts the middle of next week. It's fair to say precipitation is expected at some point after Monday, with snow possible above 8000-9000ft, but rain impacts will not be as significant as what just occurred with the remnants of Hurricane Rachel. There also should be an increase in winds ahead of the trough, likely Tuesday, which could result in wind impacts. Low confidence though in exact timing of rain, where the highest impacts will occur, and how much snow to expect in the higher elevations.With the incoming system and the potential for rain, temperatures will cool and remain below normal early next week when the system moves inland.

Aviation

For Harry Reid...For the 12Z Forecast Package... Northeast breezes continue today, strongest between now and sunset with gusts 15-30 knots. Winds should begin to subside after sunset, eventually falling below 10 knots and becoming variable in direction overnight. Clear skies until high clouds begin to move in early Saturday morning.

For the rest of southern Nevada, northwest Arizona and southeast California...For the 12Z Forecast Package...Gusty winds continue today, strongest from now through sunset with gusts generally 15-30 knots. In the southern Great Basin, winds direction will generally be more easterly, with southeast winds in our far northwestern areas. Across the Mojave Desert, expecting more northeasterly winds. Somewhat low confidence wind forecast for the lower Colorado River Valley this afternoon/evening as winds try to turn more east/southeast. However, breezes weaken across the area after sunset. Mostly clear skies with just some high clouds moving in from the south tonight.

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DISCUSSION...Nickerson AVIATION...Woods

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