Area Forecast Discussion
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
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166 FXUS65 KRIW 222219 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 419 PM MDT Sun Sep 22 2024 .KEY MESSAGES... - Dry and seasonal the next few days. A weak cold front Monday brings a breezy north wind. - A warming trend starts the middle of next week, with 80 degree temperatures returning for many locations. No precipitation expected through the end of next week. && .DISCUSSION... Issued at 1234 PM MDT Sun Sep 22 2024 An upper low to the south continues to shift eastward today. As a result, some warmer air is allowed to filter in over Wyoming. Highs today will therefore be more seasonal, (compared to yesterday`s cooler temperatures) with highs generally in the 68F to 78F range. No precipitation expected today, with a mostly to completely clear sky. The next weather feature moves in by early Monday morning, as a trough moves through the area. Model trends have continued to dry out this system, with recent runs even shifting the trough axis eastwards. Have removed precipitation chances for Monday as hi-res models are in agreement on the dry conditions; would just expect some increased cloud cover. The main impact from this trough will be the dry cold front that pushes through. The front should begin to push in from the north by about sunrise Monday morning. As the front pushes southward, a breezy north wind follows. North wind prone locations, such as the Bighorn Basin and Johnson County, could see gusts 20 to 25 mph with this front, with maybe some near 30 mph gusts with the initial push of the front. As the back of the trough moves through between late afternoon and the evening, another surge of winds near 30 mph are possible for these locations. Models seem to be underplaying the highest wind gusts a little bit, so have increased the winds in the forecast a bit around late afternoon to early evening. Elsewhere, gusts up to around 25 mph occur with this frontal passage. Some locations, such as South Pass, could see some higher gusts as wind flows off the mountains when winds shift from the west to north. Winds decrease everywhere into Monday night. High pressure begins to build in Tuesday, with temperatures coming up. Long range models keep high pressure over the area through the rest of next week. This brings warming temperatures and dry conditions. Many locations could see the return of 80 degree temperatures, with possible near-record highs. && .AVIATION /00Z TAFS THROUGH 00Z TUESDAY/... Issued at 415 PM MDT Sun Sep 22 2024 VFR prevails through Monday at all terminals. A slow-moving upper low over Colorado tracks east tonight as an upstream kicker shortwave drops into the Northern Rockies. This shortwave swings into the Northern Plains Monday morning spreading increasing mid/high clouds into the forecast area beginning late tonight. The shortwave also nudges a weak cold front into northern Wyoming late in the forecast period. A north wind around 10-15kts follows the front which reaches KCOD and nears KWRL between 15Z-18Z/Monday. Speeds will be higher at non-TAF airports KBYG and KGEY. The front pushes into central Wyoming during the afternoon switching the wind to the north to northwest. Mid-cloud cover will be most extensive east of the Continental Divide. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on smoke, icing, and turbulence forecasts. && .RIW WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Wittmann AVIATION...CNJ/LaVoie