Expires:No;;446742 FXUS63 KLSX 291720 AFDLSX Area Forecast Discussion...Updated Aviation National Weather Service Saint Louis MO 1120 AM CST Mon Dec 29 2025 .KEY MESSAGES... - After a cold and blustery day, winds will die down tonight and temperatures will warm roughly 10 degrees on Tuesday. - Near to below normal temperatures will persist through the weekend, though uncertainty in the temperature forecast is higher than normal. && .SHORT TERM... (Through Late Tuesday Afternoon) Issued at 213 AM CST Mon Dec 29 2025 Winds continue to gust into the 30s to 40s area wide this morning as the surface pressure gradient remains tight. The surface pressure gradient will slacken through the morning as yesterday's surface low pushes eastward and a surface high spills into the area. While winds will remain elevated, gusting into the 30s, through much of the day, they will decrease in speed through tonight. Strong cold air advection in the wake of yesterday's front will continue today, resulting in high temperatures in the 20s across most of the area. By Tuesday the surface high will sink south of the forecast area, and subsequent westerly winds will help to advect warmer temperatures into the region. The WAA combined with increased sunshine will result in Tuesday's highs nearly 10 degrees warmer than today. Delia && .LONG TERM... (Tuesday Night through Sunday) Issued at 213 AM CST Mon Dec 29 2025 The warming trend will continue Wednesday, finally pushing our temperatures back to near normal. Meanwhile, a mid-level low will churn over southeastern Canada Wednesday, with a mid-level ridge over the Four Corners region, leaving the mid-Mississippi Valley in northwest flow between the two. During the day, the surface low over southeast Canada associated with the mid-level low will send a cold front southward into the upper Mississippi Valley. The dry cold front will sink into the forecast area overnight into Thursday, bringing a shot of cooler air to the region. Uncertainty still exists in if this feature will move through the entire CWA, how cold it will be, as well as how quickly it moves northward as a warm front. This results in uncertainty in temperatures from Thursday through the end of the weekend, roughly 10-15 degrees in the interquartile spread. Despite this, the 25th percentile of the interquartile spread for high temperatures during this period is only about 10 degrees below normal for this time of year, increasing confidence that this surge of cold air will be less intense than today's. By Friday the mid-level low will lift northward into the Hudson Bay region, leaving room for a shortwave to move through the southern stream of the mid-level flow, through the mid to lower Mississippi Valley. While current ensemble guidance keeps a majority of this precipitation south of the forecast area and keeps the extended forecast dry for now, changes in the track of this system could result in increasing precipitation chances across the southern forecast area. Delia && .AVIATION... (For the 18z TAFs through 18z Tuesday Afternoon) Issued at 1112 AM CST Mon Dec 29 2025 A pocket of stratus is moving across the region currently, impacting all local terminals. The base height of this stratus has been difficult to track, as the diurnal temperature curve has been attempting to raise it while the cold air advecting into the region has been working to lower it. Where this battle is going to be most impactful is at KSUS, KSTL, and KCPS where ceilings may bounce around the MVFR/VFR threshold through the first few hours of the TAF period before stratus clears the area. Within this stratus at these three terminals, there is also a low chance for flurries. Once stratus clears the local terminals, VFR flight conditions are expected through the remainder of the period as winds weaken and begin to shift to out of the west-southwest. Elmore && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX