Area Forecast Discussion
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
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377 FXUS65 KRIW 111602 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 1002 AM MDT Sat May 11 2024 .KEY MESSAGES... - A nice start to the weekend with mild temperatures and only isolated convection. - Warmer tomorrow with a better chance of showers and thunderstorms, but most places should be dry most of the day. - Unsettled for much of next week with a few rounds of showers and storms. Details for timing and placement of heaviest precipitation remains uncertain. && .DISCUSSION... Issued at 321 AM MDT Sat May 11 2024 I apologize for the lateness of the discussion today. The northern lights were absolutely stunning tonight, and this, along with the quiet weather, lead to many of our meteorologists taking trips outside to witness the best display of the aurora in many years. Personally, it is the best I have seen, and I started my Weather Service career in northern Alaska. So, back to the weather. All in all, it looks like a nice start to the weekend today with mild temperatures and light wind. The only small fly in the ointment is the small chance (less than 1 in 5) of a stray shower or thunderstorm over the mountains, courtesy of a bit of moisture and a weak upslope flow around an upper level low over Colorado. Nevertheless, a nice start to the weekend. Things do turn a bit more active on Sunday, as a shortwave drops down out of Montana and brings a better chance of afternoon convection to most of the area except the far west. The best moisture and forcing is found from roughly the Bighorn Range and east, and these are where the higher POPs (1 in 3) are found versus further west, where the chances are 1 in 4 at best. However, even in areas that get a shower or storm, it will be a small portion of the day so most of the day looks rain free even in these locations. We then enter a more active pattern to start the work week. The ridge will be pushed east and replaced by an approaching Pacific trough and cold front. Models have come into somewhat better agreement with some details with this system, with the best chance of showers and storms across northern Wyoming, where there will be some helping jet energy to enhance upper level divergence. POPs were tapered up to a 3 in 5 chance across the far north and a less than a 1 in 5 chance across the south. Southerly flow ahead of the front will bring warm temperatures Sunday and Monday, with some locations possibly reaching the 80 degree mark. Uncertainty increases starting on Tuesday and extending through the work week. A series of systems will cross the area and bring chances of showers and thunderstorms, but no major systems are expected. We do have high confidence in temperatures falling behind the front starting Tuesday, and especially Wednesday when many locations could be 15 degrees below normal. Temperatures then moderate toward the end of the week. So, to sum up the latter part of the forecast period, we have high confidence in an unsettled pattern with variable temperatures (greater than a 4 in 5 chance), but details in the timing and placement of precipitation remains rather low. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1000 AM MDT Sat May 11 2024 VFR conditions, with SKC skies, and light winds will begin the TAF period. High clouds will stream over the area from the north through the afternoon, as CU develops over southern portions of the forecast area, as well as the Bighorn Mountains. There remains a 10% chance of isolated showers and thunderstorms for these areas and have left VCSH/VCTS mentions out of the forecast, as they are not expected to pose any direct impact to any terminal. The one exception could by gusty outflow winds hitting KBPI/KPNA late this afternoon toward 00Z. Winds will remain light overnight, with mostly clear skies. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .RIW WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Hattings AVIATION...LaVoie