920 FXUS63 KILX 221057 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 557 AM CDT Sun Oct 22 2017 .SHORT TERM...(Today and tonight) ISSUED AT 335 AM CDT Sun Oct 22 2017 08z/3am surface analysis shows a slow-moving cold front approaching the Mississippi River. Most of the precipitation has been occurring along and just behind the front...with very little further east into central Illinois. Latest radar trends are beginning to show showers becoming more numerous as far east as the Illinois River Valley: however, the bulk of the precip remains further west in the immediate vicinity of the boundary. With the front moving very slowly eastward and individual showers generally tracking N/NE, have slowed the arrival of rain across the KILX CWA this morning. Based on radar trends, have kept locations near the Indiana border dry until around 14z/9am. Most high-res models show showers spreading into the area this morning in a diminishing state, then re-developing across the eastern half of the area this afternoon. End result will be a showery day, with perhaps a couple rumbles of thunder. High temperatures will range from the lower 60s northwest of the Illinois River...to the middle 70s in the Wabash River Valley. An upper wave currently evident on water vapor imagery over the Oklahoma/Texas panhandles will track eastward and eventually close off across the Lower Mississippi River Valley tonight. As it does, it will slow the eastward progression of the cold front and keep rain chances alive across much of the area tonight. Will bring the showers to an end along/west of I-55 overnight, but keep high chance to likely PoPs in the forecast further east across the remainder of the area. Low temperatures will range from the middle 40s in the Illinois River Valley...to the middle 50s near the Indiana border. .LONG TERM...(Monday through Saturday) ISSUED AT 335 AM CDT Sun Oct 22 2017 Showers will persist across the eastern KILX CWA through Monday as surface low pressure tracks along the slow-moving boundary into the Ohio River Valley. Once the low lifts further northeast, the best rain chances will depart: however, with an upper wave digging southward into the region on Tuesday, widely scattered showers and much cooler weather will be on tap. With 850mb temps progged to drop to around -3C, high temperatures will struggle to reach the lower 50s on Tuesday. Another cool fall day is expected on Wednesday before temperatures make a temporary rebound back into the middle to upper 60s on Thursday. After that, a significant cooling trend is expected by the end of the week: however, major timing differences exist among the operational models concerning the timing of the approaching upper trough responsible for the cooler conditions. The 00z Oct 22 GEM is faster with this feature, showing a closed upper low tracking north of central Illinois into the Great Lakes by Saturday morning. Meanwhile, the GFS and ECMWF are considerably slower, with the ECMWF showing the closed low meandering eastward into the Great Lakes by Monday. With such a large spread in model solutions, forecast confidence beyond Thursday remains poor. At this point, will continue to forecast showers on Friday as the upper trough and its associated cold front approach from the west. Beyond that, the precip forecast is murky at best...depending on which model verifies. What is certain however, is that temps are going to take a nosedive at some point this weekend...setting the stage for the coldest weather thus far this fall season by early next week. && .AVIATION...(For the 12Z TAFS through 12Z Monday morning) Issued at 557 AM CDT Sun Oct 22 2017 A cold front currently just west of the Illinois River will slowly push eastward today...bringing showers and MVFR ceilings to the central Illinois terminals. Latest obs show the low clouds encroaching upon KPIA, with satellite timing tools suggesting they will be there by 12z. Based on HRRR, have introduced MVFR ceilings at KSPI by 14z...then further east to KCMI by 16z. The front will eventually slow and/or stall near the Indiana border this evening. As a result, cloud cover will be very slow to clear. In fact, latest models suggest KBMI/KDEC/KCMI may hold on to their MVFR ceilings through the remainder of the 12z TAF period. Further west, have raised ceilings to VFR at KPIA by 22z and at KSPI by 00z. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Barnes LONG TERM...Barnes AVIATION...Barnes