Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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163 FXUS63 KILX 180030 AFDILX Area Forecast Discussion...Updated National Weather Service Lincoln IL 730 PM CDT Mon Jun 17 2024 .KEY MESSAGES... - Seasonably hot and humid weather will prevail this week. Heat index values will peak in the upper 90s to around 100 degrees Tuesday afternoon through Saturday afternoon. - Isolated thunderstorms will be possible from time to time over the next few days...with a better chance for thunderstorms arriving late Saturday into Sunday. && .UPDATE... Issued at 730 PM CDT Mon Jun 17 2024 Much of the lingering convection has faded away, with just a few showers left that are approaching Flora. However, high-res models continue to hint at some redevelopment after midnight over the eastern CWA, with a weak upper disturbance lifting out of the lower Mississippi Valley. The NAM Nest has been most bullish in this regard, though the HRRR has had a bit of an uptick recently as well. PoP`s have been refined a bit with timing, and to increase them to around 30% near/east of I-57 after midnight. A large part of the forecast area should be mostly cloudy as well, with plenty of high clouds streaming northeast. Temperatures are generally on track to drop into the mid 70s once again. Geelhart && .SHORT TERM...(Tonight through Tuesday Night) Issued at 307 PM CDT Mon Jun 17 2024 19z/2pm radar imagery shows isolated convection across the KILX CWA...particularly east of I-57 and west of the Illinois River. The isolated storms will persist until sunset, followed by dry conditions from mid-evening through much of the overnight period. CAMs have consistently been showing renewed convective development associated with a subtle short-wave trough pivoting northward from the lower Mississippi River Valley late tonight into early Tuesday morning. Based on model consensus, it appears most of the activity will focus along/east of I-57 after 09z/3am. Have included 20-30 PoPs across this area accordingly. After the early morning showers fade, disorganized diurnal convection will re-develop within the highly unstable airmass Tuesday afternoon. Areal coverage will remain quite low, so have only included 20 PoPs at this time. Lows tonight will only drop into the lower to middle 70s while highs on Tuesday will climb into the lower 90s. Maximum heat index values will peak in the upper 90s to around 100 degrees Tuesday afternoon. Barnes .LONG TERM...(Wednesday through Next Monday) Issued at 307 PM CDT Mon Jun 17 2024 Upper high currently centered over the Carolinas will build southwestward over the next couple of days, cutting off the flow of deep-layer moisture from the Gulf of Mexico. With this moisture shunted into Texas and remaining well S/SW of central Illinois, diurnal storm chances will decrease Wednesday through Friday. Will need to keep an eye on a weak cold front that will try to drop southward out of the Northern Plains, but think most of its associated convection will remain N/NW of the area across Iowa/Wisconsin. Have confined low chance PoPs to locations along/northwest of the Illinois River during that period, but think most locations will remain dry. Main story will be the hot weather as heat index values routinely peak at around 100 degrees. Hottest days will likely be Friday/Saturday when air temperatures climb into the middle and perhaps upper 90s in a few spots and heat index values reach 100-105 degrees. As has been advertised by the models for the past several runs, a significant short-wave trough is expected to traverse the country and push a cold front into central Illinois this weekend. 12z Jun 17 GFS and ECMWF are in relatively good agreement, showing the front arriving Saturday night. As a result, have included chance PoPs (30-50%) Saturday night into Sunday. Once the front departs, cooler and less humid weather is expected early next week as highs drop back into the middle to upper 80s by Monday. Barnes && .AVIATION... (For the 00z TAFs through 00z Tuesday Evening) Issued at 624 PM CDT Mon Jun 17 2024 Scattered convection is fading as sunset approaches, but some high-based ceilings will spread northward this evening with the remnants. Some indications of lower ceilings near 5000 feet for a time at KDEC/KCMI toward sunrise, before improvements take place once again. For the most part, southerly winds will remain gusty through the entire forecast period, 20-25 knots, but may subside for a time tonight. Geelhart && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$