Area Forecast Discussion
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
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838 FXUS65 KRIW 181040 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 440 AM MDT Wed Sep 18 2024 .KEY MESSAGES... - Strong winds off the east slopes of the Absarokas and Bighorns through midday. - Widely scattered rain showers (snow for higher terrain) for the northern half of the CWA off and on all day Wednesday. - Dry conditions Thursday with cooler temperatures and sporadic precipitation chances Friday and over the weekend. && .DISCUSSION... Issued at 1234 AM MDT Wed Sep 18 2024 IR currently depicts a classic comma cloud signature from the high plains to the northern Rockies with much of the colder cloud tops out of the state. Radar shows some lingering rain showers and light snow for the higher terrain across northern parts of the CWA that will continue to wrap around off and on throughout Wednesday. The cold front is now well to the east with ample CAA pushing into the state reinforcing the gusty westerly winds through the morning hours. Boundary layer winds have 50 plus knots that could mix to the surface under the ample cloud cover not capped aloft. The main focus areas for any high winds will be off the east slopes of the Absarokas funneling through the Cody foothills, as well as across the Rattlesnakes to Natrona County. Winds will finally start diminishing towards noon Wednesday and into the afternoon hours as the gradient weakens in wake of the occluded front exiting to the east with the main upper level low. Behind it will be induced ridging for Thursday that will dry out the state but continue with the cooler, more seasonable temperatures to end the work week and over the weekend for the long term. Next up will be another upper level low making its way down the west coast towards the Four Corner Region. Models are now indicating more alignment with one another pushing it further south with less of an impact to the CWA. Cooler temperatures will still be had with breezy winds Friday and into the weekend, but precipitation chances look to be more minimal as the shortwaves spin around the aforementioned low. Higher terrain look to be most impacted with some weak mountain snow as well as some rain showers for south central Wyoming as the low tracks east across the southern states. The main jet will be cut off to the north keeping the more potent lows with much colder air near the Canadian border and into Canada. Longer term forecasts have much model disagreement with some interesting weather patterns to come by mid next week all dependent on some trough/low tracks coming down from the GOA through the Pacific northwest. Time will tell, so stay updated in the coming days. All in all, once this current upper level low track eastward later today, expect calmer yet somewhat unsettled weather to come keeping the cooler temperatures going forward. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 430 AM MDT Wed Sep 18 2024 VFR conditions will prevail at all locations but JAC, where MVFR will be the main prevailing ceiling through the morning hours until 18Z. Mid level ceilings at all other locations with breezy winds gusting up to 25 kts, highest at CPR up to 40kts and COD/LND up to 30 kts. Light rain showers at JAC/COD/WRL will continue through much of the day before ending by 23-00Z as the main low exits to the east. Winds will diminish after 01-02Z as an inversion is able to cap them off aloft with scattering mid to upper level clouds improving overnight into Thursday morning. 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... High Wind Warning until noon MDT today for WYZ003-019-020. && $$ DISCUSSION...Lowe AVIATION...Lowe