Area Forecast Discussion
Issued by NWS Las Vegas, NV

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924 FXUS65 KVEF 250610 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 1110 PM PDT MON OCT 24 2016 .SYNOPSIS...Showers and isolated thunderstorm activity will become more scattered tonight and gradually diminish from west to east by Tuesday early morning. Pleasant conditions will return Tuesday through Thursday before more active weather returns Friday through the weekend. && .UPDATE...Made some significant changes to the forecast for the next 24 hours. First order of business was to update the PoP/QPF/Sky forecast through 12z. The band of precip that has been moving across through the afternoon and evening continues to progress a bit slower than forecast. As such, I added showers to the forecast across eastern San Bernardino County and increased PoPs significantly across Mohave County where the brunt of the activity is expected over the next 6 hours. Also removed PoPs from Lincoln County where precip has ended and skies are clearing out. Also dropped both high and low temperatures for the next 24 hours and raised dew points and RH`s. In fact fog is a distinct possibility in areas that received rain today and is already beginning to form around Kingman. Additional areas of fog will be possible as mid to high level clouds clear out through the morning hours. Additional updates possible to handle fog and the end of shower activity as the morning progresses. && .AVIATION...For McCarran...Most shower activity is now in the Peach Spring corridor, and will continue to press east overnight. In general skies will gradually clear overnight. However, with wet surface conditions in the valley patchy low clouds or even fog are a distinct possibility overnight. Winds will be light and variable overnight. During the day expect light winds to return to a typical diurnal pattern with a FEW-SCT clouds at 5-10kft. For the rest of southern Nevada...northwest Arizona...and southeast California...Line of showers and embedded thunderstorms moving east will impact eastern San Bernardino County, Colorado River Valley and Mohave County through tonight. Generally clearing skies expected behind the line, and could lead to areas of low clouds/fog during the morning hours. Mainly light and variable winds overnight. During the day expect light winds to return to a typical diurnal pattern with a FEW-SCT clouds at 5-10kft. && .PREV DISCUSSION... 300 PM PDT MON OCT 24 2016 .SHORT TERM...through Wednesday Night. Heaviest rainfall during this event has occurred in a corridor from Barstow-Pahrump/Spring Mountains-Alamo. Some 24 hour rainfall totals through 2 pm within the corridor include: Barstow, CA 0.50 Shoshone, CA 1.16 Pahrump, NV 1.17 Kyle Canyon, NV 1.98 Rainbow Canyon, NV 2.28 Alamo, NV 0.86 So far the official station at McCarran International Airport has registered 0.18 inches with the valley as a whole between a tenth and a quarter of an inche. The exception would be the far west central valley out near Red Rock near a third of an inch and locally up to two-thirds of an inch in southeast Henderson/Railroad Pass. Since late morning, line of numerous showers and embedded thunderstorms has been running along Interstate 15 from southern California into southwest Utah. Based on the current movement of this line worst looks to be over for Las Vegas and areas northwest of Interstate 15. Placed highest POPs this evening in part of Eastern San Bernardino, eastern Clark, Colorado River Valley and Mohave County as line shifts eastward. This is good news for the lower Colorado River Valley and Mohave County which so far have seen little rainfall. Last of the rain should be moving out of eastern Mohave County between 11 pm and 2 am tonight. A return to our more typical desert weather expected Tuesday through Wednesday night as ridge amplifies over the Intermountain West as the next trough takes shape in the eastern Pacific. .LONG TERM...Thursday through Monday. It looks like a fairly active pattern through the weekend as an area of low pressure move inland late in the week and also the possibility of moisture form Hurricane Seymour getting into the picture. The models are still showing differences in timing with the ECMWF model continuing to be the faster run. By Thursday afternoon the EC already has precipitation reaching the southern Sierra while the GFS/Canadian models keep the moisture off shore until early Friday morning. However, the current track and position of the low that will impact the is similar with all the model runs and it still look like Inyo, Esmeralda, and central Nye Counties will see a significant rain event Friday. Snow levels will generally be around 10K feet where several inches of snow will likely accumulate at the higher peaks. Rain shadowing looks to be rather minimal due to the southwest flow of the system. So places like Death Valley could see some decent rain on Friday. Although the more widespread rain will remain over the northwest portions of the forecast area, southern Nevada, eastern San Bernardino, and Mohave Counties will also see at least a chance Friday afternoon and evening. Rainfall amounts over those areas are expected to be much less. However, moisture from Hurricane Seymour could also come into play late in the week which could throw a wrench into how much and where precipitation falls. For now will increase pops with more areas in the likely category for the northwest zones, but keep southern areas in the chance range. There are some additional differences in the models on Saturday as the GFS show a second wave and qpf spreading over mainly the two thirds of the area while the ECMWF has generally dry conditions areawide. Its possible that the GFS is hanging on to additional Seymour moisture that the EC is not picking up on. No additional changes to the grids based on these new and different runs. The models do show another low approaching northern California Sunday afternoon with additional moisture spreading into the southern Sierra, but this system is forecast to move rather quickly and most of the area is expected to be dry by Monday and Tuesday. Temperatures will generally remain around normal, but areas under thicker clouds and precipitation will see cooler temperatures. && .SPOTTER INFORMATION STATEMENT...Scattered showers and thunderstorms are expected this evening southeast of Interstate 15. Spotters should report significant weather according to standard operating procedures. && $$ Update/Aviation...Wolcott Short Term...Pierce Long Term...Gorelow For more forecast information...see us on our webpage: or follow us on Facebook and Twitter is the U.S. government's official web portal to all federal, state and local government web resources and services.