070 FXUS63 KILX 281730 AFDILX Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 1230 PM CDT Sun Apr 28 2024 .KEY MESSAGES... - Flood Watch remains in effect for locations along and north of a Rushville to El Paso line through 10 am. Between 1 and 2 inches of rain has fallen since Saturday evening, and up to 1 inch of additional rain is possible by mid morning. This heavy rainfall may lead to flash flooding. - Another round of strong to potentially severe thunderstorms expected this evening. Highest severe probabilities will be focused west of I-55. - Breezy south winds will gust between 30 and 40 mph again today. There is a 30-60% chance of wind gusts greater than 40 mph this morning east of the IL river and north of I-70. && .UPDATE... Issued at 1102 AM CDT Sun Apr 28 2024 15z/10am surface analysis shows a 1004mb low over Kansas with a cold front extending southward into Texas. A band of convection ahead of the storm system driven largely by the nocturnal low- level jet continues to rapidly dissipate along the Mississippi River this morning. Models have a good handle on the current trends and suggest a period of dry weather across central Illinois through mid-afternoon before widely scattered showers/storms begin to develop along/west of I-55 after 20z/3pm. As the cold front slowly approaches from the west and the nocturnal jet once again strengthens after dark, showers and thunderstorms will become more widespread across the Illinois River Valley this evening...with the convection spreading eastward across all of central Illinois overnight. Severe weather risk looks to remain low given only modest MUCAPEs of 1000J/kg or less: however, a few of the cells could produce gusty winds/hail west of I-55 through midnight. Barnes && .DISCUSSION... Issued at 400 AM CDT Sun Apr 28 2024 Large MCS affected parts of central and nw IL since Saturday evening brought a few strong to severe storms Sat evening along with heavy rains to areas from I-55 nw where some areas had 1 to 2 inches with locally 2-3 inch amounts over the IL river valley. Continued the flood watch until 10 am from Schuyler, Mason, Tazewell and Woodford counties nw where up to an additional 1 inch of rain possible before showers and thunderstorms diminish. Radar loop does show a weakening trend of this convection as outflow boundary has raced ahead of the convection and approaching Gibson City, Decatur and Taylorville. South winds 8-18 mph and few gusts 18-28 mph was keeping mild temps in the 60s with Galesburg and Macomb down to 59F. Latest CAMs show convection diminishing over the IL river valley by mid morning, and lasting longer over far NW CWA into late morning. May be able to cancel the flood watch over the IL river valley a few hours early if this weakening trend continues. Much of area east of I-55 will be dry most of today along with breezy south winds gusting back up to 30-40 mph. Warm highs ranging from the mid 70s over nw CWA to 80-85F in southeast IL where more sunshine possible. 1003 mb low pressure over north central KS to lift northeast toward the upper MS river valley during overnight while pulling a cold front eastward toward far west central IL by dawn Monday. Around a 50 kt SSW to SW low level jet over IL tonight along with PW values peaking 1.5-1.7 inches to likely develop another band of shower and thunderstorms moving over the IL river valley this evening and into eastern/se IL overnight. SPC day1 outlook continues marginal risk of severe storms tonight, with slight risk southwest of Macomb and Springfield for large hail and damaging winds this evening. There is a 2% to less than 5% risk of tornadoes west of highway 51. Instability is not as high today as yesterday with CAPES less than 1000 j/kg, though wind shear becomes stronger at 30-40 kts western CWA this afternoon and evening. Lows overnight mostly in the lower 60s with mid 60s near the Indiana border where rain chances arrive later tonight. Low pressure to lift north of WI by late Mon afternoon and pulling a weakening cold front eastward across IL. This shifts the greater chances of showers and a few thunderstorms into eastern/se IL on Monday. SPC day2 keeps marginal risk of severe storms Monday well south of IL as instability is even weaker than today. Highs Monday mostly in the lower 70s with breezy sw winds gusting 20-30 mph. Have a chance of showers lingering in southeast IL Monday evening, otherwise dry Monday night and Tuesday as weak high pressure settles into the area. Nice weather on Tuesday with ample sunshine, lighter winds and mild highs in the mid to upper 70s along with drier dewpoints in the low to mid 50s. A good day for outdoor activities. Dry weather will be short lived unfortunately as a wx system off the Pacific Northwest Coast tracks eastward into the upper MS river valley by midnight Tue night. This brings a chance of showers and isolated thunderstorms into the IL river valley Tue evening and into rest of central IL overnight Tue night, while southeast IL se of I-70 mostly stays dry Tue night. SPC Day3 outlook has marginal to slight risk of severe storms Tue afternoon and Tue evening west of IL over central/western Iowa and nw MO. Briefly dry over CWA Wed morning as the northern stream system exits. But quickly on its heels is a disturbance ejecting out of the central high plains with a warm front lifting northward into central IL Wed afternoon. This will bring more chances of showers and thunderstorms from Wed afternoon into Wed night. A better chance of convection on Thu and Thu night and diminishing from the west during Friday as cold front pushes eastward over IL. Will need to watch for risk of strong to possibly severe storms from Wed afternoon into Thu evening though stronger instability appears to be sw of central IL. Warm highs Wed and Thu in the lower 80s over much of the area. Highs Fri in the upper 60s and lower 70s in central IL and mid 70s in southeast IL. The Climate Prediction Center (CPC) 6-10 Day outlook for May 3-7 has a 40-50% chance of above normal temperatures over central and southeast IL, with a 35-40% chance of above normal precipitation. So the mild and unsettled weather pattern looks to continue through the 1st week of May. 07 && .AVIATION... (For the 18z TAFs through 18z Monday Afternoon) Issued at 1229 PM CDT Sun Apr 28 2024 A cold front will slowly approach the central Illinois terminals through the period. Breeze S/SW winds will prevail through the period gusting to near 30 kt during the day today but tapering off some overnight. A slow moving line of showers and storms will work across central Illinois this evening and overnight. The better chance for storms will be across the western most areas with the threat diminishing some with eastward extent. Lower MVFR ceilings will accompany and follow the line of storms. Deubelbeiss && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$