029 FXUS65 KCYS 062126 AFDCYSArea Forecast Discussion National Weather Service Cheyenne WY 326 PM MDT Mon Oct 6 2025
.KEY MESSAGES...
- Freeze Warnings and Frost Advisories are in effect for portions of southeast Wyoming and western Nebraska Tuesday morning.
- Warmer, drier conditions return mid-week.
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.SHORT TERM /THROUGH TUESDAY NIGHT/... Issued at 322 PM MDT Mon Oct 6 2025
A dreary day continues across most of the forecast area with cool, below average temperatures and widespread cloud cover. Visible satellite imagery shows a blanket of low stratus for most areas east of the Laramie Range, but partial clearing is beginning to take place in Carbon County and some of the northern zones. With some upper-level energy still lingering over the CWA, cannot rule out a few isolated light showers this afternoon, but, more than likely, most areas are done with precipitation for the day.
Heading into tonight, clearing will continue, with clouds expected to clear out of a majority of the forecast area. With the upper-level trough slow to move out, clouds will likely linger around and just north of the Interstate 80 corridor between Laramie and Sidney. Due to the cloud cover, these areas will likely stay a tad bit warmer than other areas with lesser chances for the development of frost, however cannot rule out some patchy frost in isolated areas. The rest of the CWA is likely to see clear and calm conditions overnight. As a result, temperatures will tank due to efficient radiational cooling, especially in southeast Wyoming. Areas west of the Laramie Range as well as Converse and Niobrara Counties will likely see widespread frost and temperatures below freezing overnight. Freeze Warnings remain in effect for portions of southeast Wyoming that have not yet seen a freeze this season. The frost potential will also spread into areas further east. The northern Nebraska panhandle and northern Goshen County will likely see frost develop overnight with calm and clear conditions as well as higher humidity. Issued a Frost Advisory for these areas as sensitive vegetation could be affected despite temperatures not reaching freezing.
By Tuesday, weak ridging will begin to move into the Rockies, causing temperatures to warm. Cold morning temperatures will warm quickly, with highs climbing into the 50s and 60s as 700 mb temperatures above 0C return to the CWA. Subsidence under the ridge will keep precipitation chances at bay with most locations expected to have mostly sunny skies throughout the day. Heading into the overnight hours, low temperatures will return to seasonable for the beginning of October.
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.LONG TERM /WEDNESDAY THROUGH MONDAY/... Issued at 322 PM MDT Mon Oct 6 2025
At the start of the long term, a weak upper level trough and associated shortwave pushes through our CWA, with little to no moisture in the mid-levels, precipitation chances will be minimal. This will quickly be replaced by an upper level ridge that builds north into our area late Wednesday, bringing relatively benign weather across most of our CWA through Friday. However, a weak shortwave will slide across the region and increase chances of precipitation primarily for our western zones Friday into Saturday. All this is ahead of a deep upper level trough that moves into the West Coast Saturday and progresses east into our CWA by Sunday then quickly exiting to the northeast on Monday. Most of the energy, at this time, appears to skirt just to our north which keeps most of the precipitation chances out of our area. So, what about temperatures, with the upper level ridge building across our CWA Wednesday and Thursday, this will bring warmer 700 MB temperatures in the 5 to 8 degree Celsius range which will result in surface temps climbing into the 60s west of I-25 and 70s to the east for Wednesday. Expect slightly warmer temps for Thursday into Saturday with highs topping out in the 70s and 80s, highest across eastern Wyoming and the Nebraska Panhandle. A sign that winter is coming, overnight lows through the long term period will dip into the 30s and 40s.
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.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1155 AM MDT Mon Oct 6 2025
A weak upper level disturbance will slide across the CWA today with conditions slowly improving for all terminals throughout the afternoon generally from north to south. In the meantime, the main cloud deck is pretty locked in for a majority of the terminals, especially those east of I-25. MVFR CIGs are holding firm for KCYS, KLAR, KBFF, KCDR, KSNY, and KAIA. Based on the latest VIS satellite imagery, clouds appear to have broken up pretty nicely for KRWL. Overall, expect CIGs to lift and conditions to improve for all terminals by 01Z and throughout the remainder of the TAF period. KCYS may see a return of lower CIGs late tonight with improvement in the morning hours, by about 15Z.
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.CYS WATCHES/WARNINGS/ADVISORIES... WY...Frost Advisory from midnight tonight to 9 AM MDT Tuesday for WYZ108. Freeze Warning from midnight tonight to 9 AM MDT Tuesday for WYZ101-102-104-110-111. NE...Frost Advisory from midnight tonight to 9 AM MDT Tuesday for NEZ002-003-095-096.
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SHORT TERM...SF LONG TERM...RZ AVIATION...RZ
NWS CYS Office Area Forecast Discussion