270 FXUS63 KILX 292339 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 539 PM CST Wed Jan 29 2020 .SYNOPSIS... Issued at 237 PM CST Wed Jan 29 2020 Skies will continue to be cloudy overnight with some evening flurries. Patchy fog will be developing Thursday morning. Low temperatures will be in the 20s. Cloudy with high temperatures in the lower to mid 30s are expected Thursday. && .SHORT TERM...(This evening through Thursday) ISSUED AT 237 PM CST Wed Jan 29 2020 Weak short wave tracked in the satellite data had reached a eastern IA to southeast MO line this afternoon. Wave will continue to move to the east overnight, dragging some minor pcpn in form of flurries across central IL during the evening. Soundings continue to depict significant moisture trapped beneath strong low level inversion and this pattern will continue overnight and through the day Thursday. As a result, even though the upper level system moves through, significant cloudiness will continue over the area. Patchy fog developing late tonight expected, in subsidence behind the upper system. However, fog expected to be patchy with visibilities in the 2-5 range due to ample low level moisture, however no clearing expected. Weak high pressure over the region Thursday, then next system moves into the central plains. .LONG TERM...(Thursday night through Wednesday) ISSUED AT 239 PM CST Wed Jan 29 2020 Cloudy but increasingly warm conditions are expected to close the week and continue into the weekend. A broad upper level trough will shift from the Upper Midwest Thursday night to the Appalachians Sunday. As this occurs, a series of shortwaves will dig across the mid Mississippi Valley, though there remain differences in precise timing and track of these features. Forecast soundings do show very shallow moisture trapped under a persistent inversion through the weekend. Temperatures aloft do not appear to be cold enough nor moisture deep enough for ice nuclei to be present in the column. As such, the main concern would be the possibility of some drizzle at times, possibly freezing depending on timing and surface temps. Friday morning through midday Saturday appears to be the most favorable time when upper level support would be most conducive to squeezing out some light precip, though confidence if fairly low given how shallow the moisture is expect to be and with PWats under a third of an inch. As the main upper trough axis shifts east later Saturday into Sunday, warmer temperatures will arrive in its wake attendant with upper ridge building overhead. Temperatures should warm into the 50s for all but perhaps areas north of the Illinois River Valley on Sunday, contingent on clearing skies as strong subsidence aloft and deepening mixing from increasing southwest flow finally help to erode the stratus that will be stuck in place the next several days. Temperatures look to be a little more tricky on Monday as the baroclinic zone sets up across the local area. Tail end of a cold front associated with low pressure moving across Ontario will push into central Illinois and stall as another low begins to take shape over the central Great Plains. There is some uncertainty on the placement of the boundary, but likely will be looking at sharp temperature contrast across the front with 50s in the warm sector and 30s in the cold. Meanwhile, precip chances will increase in the vicinity of the front later Monday through Tuesday night as the surface low shifts east across the lower/mid Mississippi Valley. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 539 PM CST Wed Jan 29 2020 MVFR ceilings will prevail through the entire 00z TAF period. A weak upper-level disturbance will bring a period of very light snow or flurries to the area this evening, with latest radar imagery suggesting lowest visbys of 2-3 miles in snow will be focused around KSPI over the next couple of hours. Once the light snow departs later this evening, patchy fog will develop tonight into Thursday morning. Have lowered visbys into the 2-3 mile range at all terminals from 07-09z through 15z accordingly. Winds will remain light/variable. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...Goetsch SHORT TERM...Goetsch LONG TERM...Deubelbeiss AVIATION...Barnes