####018005973#### FXUS65 KCYS 030905 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 305 AM MDT Fri May 3 2024 .KEY MESSAGES... - A cold front will move through the region today with another round of shower activity in the mountains and isolated thunderstorms over the southern Nebraska Panhandle. Snow levels will remain above 6500 feet. - Mainly dry and warmer conditions are anticipated for the weekend. - Breezy to windy, and cooler weather expected for Monday through Wednesday, with isolated to scattered late day showers and thunderstorms. && .SHORT TERM /THROUGH SATURDAY NIGHT/... Issued at 305 AM MDT Fri May 3 2024 Today...A progressive and positively tilted shortwave trough aloft moves from western Wyoming this morning to central Wyoming by mid afternoon and to eastern Wyoming by late afternoon. Its associated fairly strong cold front moves quickly across our counties by late afternoon with winds turning to the north and increasing. With ample low and mid level moisture, and decent frontal lift along with dynamic lift supported by 500-300 mb and 700-500 mb quasigeostrophic lift, we anticipate scattered to numerous showers spreading from our western counties this morning to our southern and eastern counties this afternoon, along with isolated thunderstorms mainly east of I- 25. Snow will fall over the higher elevations of the Snowy and Sierra Madre Ranges with amounts from 4 to 7 inches, however with the snow falling during the daylight hours, there will likely be some melting and compacting of the snow, thus no advisory issuance seems necessary. With the strength of the cold front and the blustery north winds, it will feel rather chilly for early May. Tonight...Precipitation will end quickly this evening as the shortwave trough aloft moves off to our east. Looks like a cold overnight as surface high pressure builds southward across eastern Wyoming and western Nebraska and skies become clear. Saturday...Transitory shortwave ridging aloft will build overhead and with plenty of sunshine and 700 mb temperatures near 2 Celsius, maximum temperatures will reach the mid 50s to mid 60s, with southeast low level winds limiting the warmup. Saturday night...Decent moderation in temperatures will occur as southwest flow aloft strengthens ahead of the approaching trough aloft over the Great Basin states, inducing increasing south winds and a thermal ridge over our counties, with low temperatures from the mid 30s to lower 40s. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Issued at 305 AM MDT Fri May 3 2024 Sunday will be the warmest day of the weekend as a shortwave ridge axis moves just to the east ahead of a large scale upper level low moving towards the central Rockies. 700mb temps will warm near 6-10C with afternoon temperatures reaching the upper-60s and 70s ahead of increasing cloud cover with the approaching upper level low. Areas west of the Laramie Range, especially southwest Carbon Co and the Sierra Madres will begin to see increasing moisture Sunday night leading to accumulating snowfall above 7500 ft elevation. Based on the upper level low track, the majority of wrap around moisture will most likely develop farther north and east. However, lee troughing across much of the WY Front Range will lead to increasing mslp gradients and the potential for strong westerly winds across our area starting Monday. Latest NBM probabilities of 55+ mph wind gusts are quite high (>80%) for most wind-prone areas across southeast WY with areas covered by 50% probabilities expanding outside of wind-prone locations onto adjacent foothills and plains. Additionally, in-house guidance has been showing high probabilities (60-80%) for high winds, however there still remains run-to-run uncertainty with the duration and timing of strongest winds. This should clear up as models continue to get a better idea on the low track and evolution. Right now, the timing for the strongest winds appears to be Monday afternoon with 700mb flow climbing over 60 kt across southeast WY and 850mb (700mb) CAG-CPR height gradients exceed 70m (60m). Latest cluster analysis shows ~45% of EC membership favors a slightly farther south track that will lean towards stronger wind speeds aloft over our area. Overall, there remains strong ensemble support for high winds early next week with latest NAEFS and EC showing over climatological 99th percentile 700mb winds. This upper level low looks to stall out across the central CONUS leaving southeast WY and western NE under a general troughing pattern through the remainder of the week. This will lead to below average temperatures for early May with additional chances for light precipitation. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1047 PM MDT Thu May 2 2024 VFR prevails over the next 6-12 hours for the majority of south east Wyoming and the western Nebraska Panhandle with BKN to OVC cloud coverage between 8k and 12k feet AGL. Ceilings are likely to gradually lower overnight, falling to between 3k and 6k feet AGL for most terminals on Friday morning, first impacting those areas mainly along and west of the Laramie Range in the morning before spreading onto the plains during the afternoon. Isolated to widely scattered rain and/or snow showers should become more widespread with time, with potential for MVFR/IFR conditions at some terminals impacted by heavier bands. A broader area of low stratus may impact KCDR/KAIA during the mid to late morning and early afternoon, with IFR ceilings possible. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...RUBIN LONG TERM...MB AVIATION...CLH ####018006153#### FXUS65 KVEF 030908 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 208 AM PDT Fri May 3 2024 .SYNOPSIS...Dry conditions with seasonably warm temperatures are expected through Friday. Over the weekend, a strong system will move through the region bringing widespread strong winds along with much cooler temperatures. Precipitation in the southern Sierra Saturday will spread across parts of southern Nevada Saturday night and Sunday Improving conditions are expected early next week with temperatures slowly moderating. && .SHORT TERM...Through Sunday night. Everyone enjoy today, because the weekend will be quite turbulent. There is a weak shortwave moving through southern Idaho early this morning. Radar is detecting some light showers over northern Utah with lower clouds extending westward through central Nevada, as far as Fallon. In southern Nevada and the Mojave Desert skies are clear with light winds. Skies will stay mostly clear today with afternoon clouds developing over the mountains of Inyo County and central Nevada. Temperatures will top out around 5 degrees above normal. For the weekend, we are still tracking a potent trough that will drop from the Gulf of Alaska. The trough will move east across northern California and northern Nevada Saturday night through Sunday. Primary impact for the entire region will be the onset of strong south to southwest winds Saturday. Latest guidance suggests the strongest winds through 5 pm Saturday afternoon will likely be occurring in the Spring Mountains, Nye, Esmeralda and Inyo Counties. Specifically for Inyo County, not seeing a significant downslope signature through 5 pm Saturday but the cross section does indicate strong southerly winds up the Owens Valley. Current hi-res guidance is only going through 5 pm Saturday so its possible those downslope winds may not develop until the evening, coinciding with the trough axis. Best timing for potential high winds greater than 58 mph for southern Nye County, Spring Mountains and Las Vegas Area will be Saturday night into Sunday morning. That period looks to be 8 pm Saturday evening through 8 am Sunday morning. NBM probability for wind gusts >58 mph ranges between 30%-50% from Mountains Edge north to Skye Canyon. Central and eastern parts of the valley mostly 20% or less. Downward trend in the wind speeds will commence Sunday afternoon into the evening. Hi-res guidance is only out through Saturday afternoon but I'd love to see a cross section across the Spring Mountains and the valley through Saturday night. For that reason, kept with the high wind watch which will allow the next shift to hopefully make a more precise decision on which zones need to be included in a warning and which will fall under the wind advisory. Regarding precipitation. Light showers will begin in the southern Sierra Saturday afternoon then spread east of the Sierra into southern Nevada Saturday night and Sunday. Up to 2" forecast for Aspendell in the southern Sierra. Similar amounts possible for the mountains of northern Lincoln County. 0.5" or less for the Spring Mountains and Pioche. Temperatures will start to cool across the northern areas on Saturday with much cooler conditions areawide on Cinco de Mayo. In fact, forecast high of 67 for Las Vegas Sunday is only two degrees warmer than our low maximum record of 65 set in 1973. .LONG TERM....Monday through Thursday. As the weekend system moves out, our area will be left under mostly zonal flow with a touch of a NW component. This pattern looks to linger through most, if not all, of the work week as persistent troughing remains just to our north. At the surface, this results in breezy afternoons with highs roughly 3-8 degrees below normal across the area. We'll remain dry as the troughing to our north has very little moisture to work with. PoPs stay below 10% through Thursday. .AVIATION...For Harry Reid...Winds will remain light and will follow typical diurnal directional patterns through early afternoon when winds will pick up and swing to the southwest. These southwesterly winds will persist through tomorrow morning with wind speeds decreasing during the overnight hours before picking back up on Saturday morning. Wind gusts in excess of 35 knots are expected on Saturday and Sunday with a 60% to 70% chance of wind gusts in excess of 45 knots late Saturday evening through early Sunday morning. For the rest of southern Nevada, northwest Arizona and southeast California...VGT will follow similar trends to LAS with light and diurnal winds picking up and swinging around to the southwest during the afternoon hours. HND will favor a southerly to southwesterly direction through the evening hours with winds picking up slightly during the afternoon hours. Light and variable winds will pick up and swing around to the south later this morning at the Colorado River Valley TAF sites. These southerly winds will continue into the evening hours when EED will become more southwesterly while IFP becomes more southeasterly. DAG will favor a more westerly component with winds decreasing and becoming west-northwesterly this morning before picking back up and shifting to the west-southwest during the afternoon. Light and variable winds will pick up slightly as they swing to the west-southwest later this afternoon at BIH. These west- southwesterly winds will be relatively short-lived as winds are expected to shift to the northwest a few hours later during the evening hours. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ SHORT TERM...Pierce LONG TERM...Woods AVIATION...Stessman For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter