Area Forecast Discussion
Issued by NWS Las Vegas, NV
Issued by NWS Las Vegas, NV
767 FXUS65 KVEF 101523 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 820 AM PDT Fri May 10 2024 .SYNOPSIS...Scattered showers and isolated thunderstorms will develop later today, mostly across southern Nevada, Inyo and northern Mohave Counties. Gusty outflow winds will occur with any thunderstorms. Another round of isolated showers and thunderstorms will occur well northeast of Las Vegas Saturday. Sunday onward a warming trend will commence with temperatures climbing as much as 5 to 10 degrees above normal through Thursday. && .UPDATE...Still expecting some isolated to scattered shower activity today along with the potential for a handful of lightning strikes, especially across the southern Great Basin. This mornings 12z VEF sounding sampled fairly steep mid level lapse rates and a DCAPE value of 620 j/kg. Meanwhile, morning satellite imagery depicts a vort max moving through eastern Inyo County that will drop over far southern Nevada this afternoon. This feature combined with H500 temps falling to -20 to -22C will aid in fairly quick development of isolated showers by later this morning. Activity will tend to favor the higher terrain, but will drift into the adjacent valleys with locally gusty winds of 35 to 45 mph possible. With low levels remaining quite dry, any precipitation is expected to be very light, and may only amount to a little more than sprinkles in the desert valley locations. -Outler- && .SHORT TERM...through Saturday night. Skies partly to mostly cloudy across northern Inyo, Esmeralda and central Nye Counties early this morning. Skies mostly clear elsewhere. Cloud cover being driven by a small, tightly wound vorticity center over central Nevada. This feature will steadily move southwest into Inyo County by early afternoon, all of this is going on under a broad cutoff low over the area. Yesterday afternoon there were only a few lightning strikes in east central Nevada associated with SBCAPE values between 200-400 J/kg. Today the NAM shows SBCAPE values of 200-400 J/kg encompassing all of south central Nevada, as well as mainly the higher terrain of Inyo, Clark, northern Mohave, and far northeast San Bernardino Counties. Did blend camPoPs with the NBM to better capture the expanded coverage in scattered showers and isolated thunderstorms today. Gusty outflow winds likely with strongest cores as HRRR model forecast sounding DCAPE values range between 600-1000 J/kg. Little rain expected to reach the ground with less than a 10% probability of exceeding a 0.10" anywhere in our forecast area. Most of the debris clouds from the convection will gradually vanish tonight leading to mostly clear, to partly cloudy skies at worse. The cutoff low shifts east across southern Utah/northern Arizona Saturday. The best instability for the final day of any showers and thunderstorms will exist in eastern Lincoln, northern Mohave and potentially northeast Clark Counties. Elsewhere, there will be shallow cumulus as instability starts to wane. High temperatures today will be very similar to yesterday. Warmer Saturday with highs topping out close to normal. Other than those outflow induces winds, am not looking at any significant gradient winds. .LONG TERM...Sunday through next Friday. On Sunday, the aforementioned closed low will push eastward out of our forecast area as a Pacific ridge continues to build over the Desert Southwest. Temperatures will increase to above-average on Sunday and will further increase on Monday to 8-10 degrees above seasonal averages. HeatRisk increases from "Low" to "Moderate" on Monday for the desert zones as a result. Heights will remain elevated through the rest of the forecast period; however, ensemble means indicate that a shortwave trough will close off over the Desert Southwest midweek, which will allow for some modest moisture to funnel into the region as the low interacts with a longwave trough over the Intermountain West. Not expecting much in the way of precipitation, but regarding impacts, gusty winds can be expected each afternoon as a result of tightened pressure gradients. GEFS and ECMWF ensemble means disagree late-week with regard to this weak low pushing eastward out of our area vs. it retrograding back overhead and briefly getting caught in a blocking pattern with a strong high over the Pacific Northwest. As such, NBM probabilities of Las Vegas reaching its first 100 of the season continue to decrease, with the latest run showing 11% chance Wednesday and Thursday and a 27% chance on Friday. && .AVIATION...For Harry Reid...Light and variable winds early this morning will turn north to northeast by mid-morning with speeds generally remaining 10kts or less. After 20Z, winds are expected to turn to the northwest and become gusty, with occasional gusts to 20kts. Scattered thunderstorms are also possible after 21Z, although most of the activity is expected to remain over the higher terrain surrounding the valley. Any storms that do develop may generate outflow winds from the direction of the storms that could affect the field. The threat of storms will end after sunset, and light northerly winds are forecast for the overnight period. VFR conditions should prevail through the TAF period, although CIGs down to 8kft AGL will be possible with any thunderstorm activity that develops during the late afternoon and evening. For the rest of southern Nevada, northwest Arizona and southeast California...Most regional TAF sites will see north-to-northeast winds continue today and tonight with speeds generally between 10-15 knots. A few scattered thunderstorms are expected across the northern two-thirds of the region this afternoon and early evening. Any storms that do develop may generate outflow winds from the direction of the storms and result in CIGs down to 8kft AGL. Away from any thunderstorm activity, VFR conditions will prevail with only FEW-SCT clouds AOA 10kft AGL. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ SHORT TERM...Pierce LONG TERM...Varian AVIATION...Planz For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter