


Area Forecast Discussion
Issued by NWS Cheyenne, WY
Issued by NWS Cheyenne, WY
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011 FXUS65 KCYS 141744 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 1144 AM MDT Tue Oct 14 2025 .KEY MESSAGES... - Areas of locally dense fog may develop this morning near the I-80 summit and over the High Plains. More fog is expected late tonight and linger into early Wednesday morning. - Another storm system will slowly move through the area late Wednesday through early Friday, bringing first showers and thunderstorms, following by chances of mountain snow and strong winds. - A few strong thunderstorms are possible Wednesday afternoon across western Nebraska and far eastern Wyoming. && .SHORT TERM /THROUGH THURSDAY/... Issued at 330 AM MDT Tue Oct 14 2025 Current IR Satellite loop shows overcast skies across most of southeast Wyoming and western Nebraska as low to midlevel moisture moves north ahead of the Pacific upper level trough currently moving onshore across the central Calif coastline. KCYS radar loop shows widely scattered showers developing and moving northeast. Can`t rule out some thunder this morning with lightning detection observing a few strikes across northern Colorado. Otherwise, precipitation is expected to be light with the primary upper level shortwave, currently across central Colorado, ejecting northeast into Nebraska later today. Behind the shortwave, expect gradual clearing and precip coverage to decrease through the afternoon. Other than some fog early this morning and late tonight/early Wednesday, pretty quiet weather with temperatures returning to the 60s today as a stationary front lifts northward as a warm front by tonight. For Wednesday, models indicate an interesting set-up across the Front Range for mid October. Fog will slowly dissipate across the high plains Wednesday morning as the warm front continues to lift north. Further west, potent upper level trough will become a closed low as it moves across the Great Basin region. High temperatures will return to the upper 60s to even upper 70s across portions of the Nebraska Panhandle. After a closer look at area soundings: in my 15+ years living here, I don`t think I`ve seen dewpoint Temps in the mid 50s across the high plains this late in the season. Not surprising to see that NAEFS is showing widespread 99th+ percentile PWATS across most of the area Wednesday afternoon, and climatological maximums (for mid- October) for mixing ratio/specific humidities. Therefore, there is some concern of strong to marginally severe thunderstorms for areas east of the I-25 corridor in additional to heavy rainfall. High res CAMs show discrete tstorm cells developing between the I-25 corridor and the WY/NE border Wednesday afternoon and pushing northeast across the region. The HRRR is a bit more aggressive, but the NAM and NAMNEST are on board too, with most of the cells well north of I-80. Increased POP across the area, but not sure how aggressive to go with the severe threat given the time of the year...and questionable forcing. Thermodynamic profiles look pretty good, with some areas closing in on 1000 j/kg MLCAPE during the afternoon and plentiful shear. However, dense cloud cover can have a big influence on convective potential this time of the year. Overall, agree with SPC`s Marginal Risk for far eastern Wyoming and the northern/central Nebraska Panhandle. For Thursday, all models show the upper level low lifting northeast from the Salt Lake City area to far northern Wyoming and southeast Montana by Thursday afternoon. Another round of precipitation is expected on Thursday with strong jet energy out ahead of the trough axis to the south of the upper level low. Any thunderstorm activity looks to be in the morning, with rain shower activity along the surface cold front, which could stall across the eastern plains in the afternoon and evening. High temperatures will return to below average on Thursday for most areas with highs in the mid 40s to upper 50s. Winds are also expected to increase with windy conditions looking more likely across southeast Wyoming. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... Issued at 1139 AM MDT Tue Oct 14 2025 Updated at 245 AM MDT Tue Oct 14 2025 Most of the previous long range forecast remains on track. Made additional adjustments to the wind forecast for late Thursday night and Friday, mainly for the wind prone areas of southeast Wyoming. In-house wind guidance is showing the potential for strong winds for Arlington and Bordeaux...and possibly the I-80 corridor and portions of Carbon County after midnight late Thursday night/Friday morning as the strong upper level trough axis moves northeast across the region. Increased winds and added gusts up to 55 MPH for now. 700mb subsidence is marginal, so did not go into High Wind criteria quite yet. Previous Discussion... Issued at 222 PM MDT Mon Oct 13 2025 At the start of the long term, a pretty robust 500mb trough is deep across the Western CONUS while ridging sits to our east over the Central Plains. As we progress through the long term period, the upper level trough will slide east into our CWA by Thursday evening, continuing on a easterly track through the weekend. So, what does all this mean for us, well, expect an active pattern through mid-week with southwest flow pumping in deep moisture. As the 500mb trough slips to our east by the weekend, upper level flow will then become northwesterly. This will bring in some changes, especially to the temperatures. Expect cooler temperatures Friday into the weekend. Also, as the cold front passes, another high wind event may be possible Thursday into Friday. At the tail end of the long term period, expect the coldest temps over the weekend while moderating some on Monday as ridging aloft builds in. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 1144 AM MDT Tue Oct 14 2025 Limited aviation concerns for nearly all terminals across the CWA through this afternoon as skies clear and winds remain relatively light. However, IFR CIGs are holding on strong at KSNY and visible satellite imagery depicts very little movement, so expect IFR to MVFR CIGs into this afternoon. Finally, hi-res guidance has FG rolling back in, decreasing CIGs and VIS for terminals across the Nebraska Panhandle (KCDR, KBFF, KAIA, and KSNY) after 04Z Wednesday, added this in their TAFs. KCYS may be impacted as well, however a bit later, added VCFG in for 09Z Wednesday. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...TJT LONG TERM...RZ AVIATION...RZ