Area Forecast Discussion
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
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154 FXUS65 KRIW 101756 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 1056 AM MST Wed Dec 10 2025 .KEY MESSAGES... - Snowfall across the western mountains begins to taper off by this afternoon, adding a final 3 to 6 inches accumulation to the higher elevations. - Strong and gusty winds will continue across southern WY through this afternoon, with some gusts near 60 mph still possible. High Wind Warnings remain in effect through tonight. - Near record highs continue east of the Divide the rest of the week into the upcoming weekend, with highs holding in the 40s and 50s. && .DISCUSSION... Issued at 218 AM MST Wed Dec 10 2025 The broad ridge across the western US continues to impact the overall lack of any semblance of a winter season so far across Wyoming, and does not look to improve this outlook for at least the next week. The current tap of moisture off the Pacific has been able to produce snowfall for the western mountains, but the warm lower valley temps keeps any precip as rainfall. A passing wave to the north will continue produce another 3 to 6 inches of snowfall for the western mountains, but the western ridge will build slightly this afternoon, pushing the moisture tap farther north, ending precip by this evening. The passing wave and cold front will keep the local gradient tight, resulting in strong and gusty winds across southern WY. A High Wind Warning remains in effect as gusts could still reach 60mph, but the frequency could be lower this afternoon. Temperatures remain particularly warm, with highs in the 40s and 50s for lower elevations, running about 5 degrees under record levels. Another cold front passes by to the north in Montana Thursday through Saturday. The moisture and energy will just clip far northern WY Thursday night into Friday morning, bringing another quick round of snowfall to the YNP, the Absarokas and the Bighorns, with minimal to no snowfall expected from the Tetons southward. The only other area of concern would be northern Johnson County, which could get a brief push of colder temperatures Friday, and some brief snowfall and gusty northwest winds could bring brief travel hazards Friday night along I-90. For the remainder of the region, the ridge will keep the warm temperatures in place through the weekend, with highs stuck in the 40s and 50s. This is troublesome for anyone that actually wants winter to arrive, especially local outdoor hockey teams that still don`t have hockey rinks for practice! && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 1055 AM MST Wed Dec 10 2025 MVFR flight conditions and light rain/snow at KJAC should begin to improve to VFR around 20Z as winds begin to pick up. Confidence in MVFR ceilings this afternoon is 20%-30% at KJAC, KRKS, KBPI, and KPNA so a SCT030 or SCT035 has been added to reflect this potential. Any low cloud/MVFR ceiling potential is forecast to end between 23Z- 02Z, with high confidence (90%+) in VFR flight conditions persisting the remainder of the TAF period. Gusty winds are expected at all West of the Divide terminals (KJAC, KRKS, KBPI, KPNA), KCPR, and KCOD this TAF period. Gusty winds at KBPI and KPNA begin to diminish between 00Z-01Z, with winds at all other aforementioned terminals remaining gusty the entire TAF period. However, there is a 20% chance in gusts diminishing after 08Z at KCOD, but given confidence is low in this occurring, opted to keep persistent gusts in TAF at this time. Winds remain around or less than 12 kts at KRIW, KLND, and KWRL but an occasional gust around 20kts is not out of question (30% chance). 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... Winter Storm Warning until 5 PM MST this afternoon for WYZ001- 002-012. Winter Weather Advisory until 5 PM MST this afternoon for WYZ008-014-015-024. High Wind Warning until 5 AM MST Thursday for WYZ019-020-022- 027>030. && $$ DISCUSSION...Straub AVIATION...Gerhardt