062 FXUS63 KLSX 310005 AFDLSX Area Forecast Discussion...Updated Aviation National Weather Service Saint Louis MO 605 PM CST Tue Dec 30 2025 .KEY MESSAGES... - There is no significant chance for precipitation into early next week. - Temperatures are expected to be within a few degrees of normal through Saturday, but warming to well above normal Sunday into early next week. && .SHORT TERM... (Through Late Wednesday Night) Issued at 243 PM CST Tue Dec 30 2025 A high amplitude mid-upper level pattern with a longwave trough over the eastern U.S. and ridge over the west will persist at least through the end of the week. This will keep the Mid Mississippi Valley stuck in northwest flow aloft through the short term. A surface high currently over Texas is expected to drift east/southeast into the Gulf through Wednesday into Wednesday night. Westerly flow will prevail across the Mid Mississippi Valley as this happens which will allow temperatures to continue to moderate from yesterday and last night's chill. Lows tonight will be around 10 degrees warmer in the mid to upper 20s and highs Wednesday will likewise be up to 10 degrees warmer than today in the low to mid 40s. Short range guidance shows a weak short wave moving across the Upper Midwest and Great Lakes in the northwest flow on Wednesday night. The surface reflection of the wave drags a cold front into southern Missouri by 12Z Thursday morning. Thursday morning lows will therefore be a little cooler in the low to mid 20s, mostly along and north of the I-70. Precip is not expected with this cold front as the aforementioned high will be lingering in the Gulf which will block moisture return. Carney && .LONG TERM... (Thursday through Next Tuesday) Issued at 243 PM CST Tue Dec 30 2025 The the mid-upper pattern persists through the end of the week, though it does attenuate somewhat with time. Temperatures will be a bit cooler again north of the cold front on Thursday, but will moderate slowly through the end of the week as the pattern slowly attenuates. Deterministic guidance shows another short wave moving from the Central Plains into the Lower Mississippi Valley Thursday night into Friday. This produces a Gulf Coast low which tries to sling some moisture back into southern Missouri, but current indications are that cooler and drier air from high pressure to the north will undercut the moisture keeping our area dry. The GFS and ECMWF continue to attenuate the pattern Sunday through Tuesday, although the LREF is showing a considerable amount of uncertainty in how fast/how much this will occur. While a warm up does appear likely to occur, the LREF high temperature IQRs increase from around 4-5 degrees on Saturday, to as much as 10 degrees Sunday through Tuesday. Dry weather is very likely to persist with fewer than 10% of the LREF members showing any precipitation. Carney && .AVIATION... (For the 00z TAFs through 00z Wednesday Evening) Issued at 604 PM CST Tue Dec 30 2025 VFR flight conditions with light westerly flow will prevail through late tonight ahead of an approaching cold front. By early morning, surface winds will veer to the northwest behind the passage of this weak and dry cold front. Lastly, a period of MVFR ceilings will drop into the area, with the highest confidence in MVFR ceilings for KUIN and the St. Louis metro terminals through late morning/midday tomorrow. Peine/Pfahler && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX