196 FXUS63 KILX 191443 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 943 AM CDT Thu Sep 19 2019 .SYNOPSIS... Issued at 329 AM CDT Thu Sep 19 2019 Warm and mostly dry weather will prevail through Friday, before a slowly approaching cold front brings heavy rainfall to portions of central Illinois this weekend. && .UPDATE... Issued at 943 AM CDT Thu Sep 19 2019 Convective cluster has been ongoing across southern Wisconsin into southern Iowa this morning. Quad Cities Doppler radar showing an outflow boundary quickly dropping southward from the storms, and should reach Moline shortly. This may help trigger a few storms in our area as indicated earlier, though some minor updates were recently sent in terms of the timing. Temperatures are generally on track, reaching the upper 80s over the south half of the forecast area where the cirrus blowoff isn't expected to be as prevalent. && .SHORT TERM...(Today and tonight) ISSUED AT 329 AM CDT Thu Sep 19 2019 A weak cold front extending from Lake Superior southwestward to Kansas has been the focusing mechanism for convection over the past few hours. The storms are most prevalent from eastern Nebraska across northern Iowa and are being aided by a short-wave trough tracking through the Dakotas. While most of this activity will remain well N/NW of the KILX CWA, several CAMs are suggesting widely scattered storms may develop as far southeast as the Illinois River Valley later this morning through the afternoon. Based on model consensus, have included low chance PoPs along/west of the Illinois River...with dry conditions expected further east. High temperatures will range from the lower 80s around Galesburg where clouds/showers will be most prevalent...to the upper 80s in the Wabash River Valley. Isolated convection may re-develop late tonight in the vicinity of the dissipating frontal boundary:however, it appears any showers/storms that form will stay just northwest of the CWA across Iowa into northwest Illinois. Lows tonight will drop into the lower to middle 60s. && .LONG TERM...(Friday through Wednesday) ISSUED AT 329 AM CDT Thu Sep 19 2019 The GFS continues to be overly aggressive with scattered convection during the day Friday, while other models such as the GEM/ECMWF remain dry. Have scaled back PoPs to include locations along/west of the I-55 corridor only...and even this may be overdone given lack of forcing and deep-layer moisture. Highs will again reach the middle to upper 80s. Main weather story continues to be the approach of a significant short-wave and its associated cold front over the weekend. Models still exhibit some key differences concerning the forward speed of the front and the corresponding QPF. Given the strength of the upper ridge initially in place over the Midwest/Ohio River Valley, think the GFS is too fast in spreading precip eastward across Illinois on Saturday. Have therefore kept PoPs mainly west of I-57...with areas further east remaining dry through the entire day. As the wave and frontal boundary push into the region and intercept tropical moisture streaming northward from the remains of Tropical Storm Imelda, widespread rain will develop late Saturday night through Sunday night. Given impressive precipitable water values increasing to over 2 inches, confidence is growing in a heavy rainfall event for at least the northern half of the KILX CWA. Based on model consensus, it appears the heavy rain axis will be focused along/north of a Paris to Shelbyville line where amounts of 2 to 3 inches will be common. Isolated higher amounts in excess of 3 inches will be possible. Rainfall will decrease further south, with areas along/south of I-70 picking up 1 to 1.50. Given tropical nature of the system and the overall lack of instability, have only mentioned chance for thunder during this rain event. The upper wave will track through the region late Sunday night, pushing the cold front into the Ohio River Valley on Monday. As a result, after some lingering showers Monday morning...a return to dry weather is anticipated Monday afternoon/night. After that, model solutions diverge as the GFS brings another wave through the region Tuesday into Wednesday while the ECMWF features dry weather. Will increase cloud cover, but will keep PoPs very low due to lack of model agreement and poor forecast confidence beyond Monday. && .AVIATION...(For the 12Z TAFS through 12Z Friday morning) Issued at 636 AM CDT Thu Sep 19 2019 VFR conditions will prevail at all TAF sites next 24hrs. SPI, DEC, CMI should all see clear skies through the morning with cirrus from storms well northwest of the state advecting in later. To keep these TAFs simple have opted for one line through TAF of scattered cirrus and light/variable winds. BMI will see more lower clouds this afternoon as remnants of scattered convection that should develop in eastern IA moves this way and dissipates. PIA however will see high clouds early with lower clouds around 7kft advecting into the area with some isolated precip. Have opted to go with broken cigs around 7kft with VCSH in the afternoon. Once precip dissipates and moves east mid clouds will become scattered and high clouds will become broken for the later afternoon. By evening scattered cirrus is all that will be left. Winds will be light and variable mainly except with the showers later this morning...southeast winds will prevail. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Geelhart SYNOPSIS...Barnes SHORT TERM...Barnes LONG TERM...Barnes AVIATION...Auten