622 FXUS65 KCYS 140452 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 1052 PM MDT Sun Apr 13 2025 .KEY MESSAGES... - Near critical fire weather concerns for low RH values and light winds for the lower elevations of east-central Wyoming and the far northern Nebraska Panhandle on Tuesday. - A cold front will drop temperatures back to near climatological average for Monday. && .SHORT TERM /THROUGH TUESDAY NIGHT/... Issued at 229 PM MDT Sun Apr 13 2025 This Sunday afternoon, have a couple showers along the I-80 corridor east of I-25. While the radar is looking busy across the border of Colorado and Wyoming, it doesn`t appear as to anything is making it to the ground as expected. RH values range between 14 to 35 across the forecast area so a brief sprinkle may not be possible until later this afternoon. However, our vort max looks to dive south out of our area by 00z. So these areas may not see a drop. Northerly winds look to continue for areas east of I-25 until Monday evening. Surface high pressure begins to drop in from the Northwest as a 700mb ridge forms over the Rocky mountains. This is going to increase the winds more so in the Nebraska Panhandle and Niobrara county then the rest of forecast area. It will be windy everywhere tomorrow, but no High wind headlines are expected to be issued for the Panhandle as winds are expected to peak at 30knots. RH values also remain 17 and 25 percent in the Panhandle so no fire weather headlines are also expected, however both the winds and fire weather concerns will be in the elevated category. Temperatures will remain the same as Sunday with the high temperatures remaining in the 50`s with some isolated 60`s possible in the Panhandle. This is due to that cooler airmass slowly pushing east but still over us during the afternoon tomorrow. Tuesday, the Upper level ridge sets over us to boost high temperatures back into the 60`s and 70`s with 30`s and 40`s into the overnight period. However, the Intermountain west will be very dry under this ridge as RH values will drop into the low teens. Gusty winds however wont be there to meet the 35 mph criteria but we may get close on Tuesday. With near critical fire weather conditions present on Tuesday, going to monitor models trends for possible fire weather headlines. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Issued at 229 PM MDT Sun Apr 13 2025 The long term forecast will see a switch to a cooler and more active pattern later in the week. Starting Wednesday night, both the GFS and ECMWF show an upper-level closed low from Canada dropping down into the Pacific Northwest. This low will slowly dive south through the end of the work week and into the weekend and largely be responsible for the cooler temperatures and precipitation chances during this time. Ahead of this system, a weak upper-level disturbance will pass over the CWA Wednesday night. Models are in good agreement, showing some light precipitation overnight, mainly along the Interstate 80 corridor and west of Interstate 25. Impacts will likely be minimal, however the mountains could see some light accumulations. Heading into Thursday, models show a bit more disagreement. Despite upper- level low placement being nearly identical in Idaho, the ECMWF is speedier to push the cold front into the CWA by Thursday afternoon. The GFS is much slower, showing frontal passage by early Friday morning. The speedier front results in a wetter solution for Thursday, while the slower front results in a wetter Friday. By Saturday, the upper-level low will dive into the Great Basin, resulting in mostly dry conditions. The mountains will likely still hang on to some lingering moisture which could lead to continued light snow at higher elevations. Temperatures will gradually decrease through the end of the work week thanks to the incoming cold front. Temperatures will start above average on Wednesday, but drop to below average by Friday as 700 mb temperatures fall below 0C. Given these cooler temperatures, it is possible for some of the lower elevation locations to see some minor snow accumulation, especially at night with temperatures below freezing. Temperatures will warm up to about average on Saturday as some of the cold air aloft is kicked out. && .AVIATION /00Z TAFS THROUGH 00Z MONDAY/... Issued at 517 PM MDT Sun Apr 13 2025 VFR conditions expected over the next 24 hours. Breezy winds are on the decline this evening, and should continue lessen most sites overnight except for KSNY which should continue to see a few gusts around 20 knots. Tomorrow morning into the afternoon, between 15-21Z, strong winds return with gusts 25-35 knots possible. High clouds are expected overnight and should be clearing, though a few lingering high level clouds in the NE Panhandle are possible tomorrow morning into the afternoon. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...MM LONG TERM...SF AVIATION...CG