Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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764 FXUS63 KILX 192035 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 335 PM CDT Wed Jun 19 2024 .KEY MESSAGES... - Hot and humid conditions will continue across central and southeast IL for many days. The hottest conditions of the upcoming 7 days look to be Friday and Saturday when air temperatures climb into the mid 90s, and heat index values peak near or just above 100 degrees. - Isolated thunderstorms will be possible mainly northwest of the IL river this evening and again Thursday, with a better chance for thunderstorms arriving Saturday night into Sunday as a cold front moves through Illinois. && .DISCUSSION... Issued at 335 PM CDT Wed Jun 19 2024 A frontal zone trailing from Lake Michigan southward to near the OK/TX panhandle area is beginning to develop some thunderstorms in the section near the Mississippi River, as well as a growing cluster in north-central MO. This activity should creep eastward late this afternoon and evening and promote at least isolated storms into the Illinois River Valley. The latest HRRR model run focuses activity just west of the Illinois River well into the evening, while other available high resolution models keep activity primarily west of the ILX forecast area. Have opted to extend PoPs farther east and later into the evening than previous forecast with this HRRR run, although kept at slight chance/20 percent. With effective bulk shear exceeding 30 kts in a corridor around the Mississippi River, SPC has continued a Marginal Risk for severe thunderstorms containing damaging wind gusts that extends into parts of Knox County. Another disturbance looks to track along the stalled front Thursday, promoting additional thunderstorm chances. High pressure and dry conditions look to prevail Friday into Saturday, then an upper level wave looks to drive the frontal zone through central IL over the weekend promoting more widespread and perhaps stronger thunderstorm activity, although at present, timing looks to be unfavorable for severe storms, arriving late at night. At this point, have 30 to 70 PoPs with this feature, highest NW of the Illinois River. Temperatures should be quite hot through Saturday, as the warm pre-frontal air mass dominates, and dewpoints around 70 are forecast. Expect highs in the low to mid 90s, peaking Saturday. Heat index should be well into the 90s, if not exceeding 100 Friday and Saturday. A bit of a respite is forecast for Sunday and Monday with temperatures maxing out around 90, then more hot weather is forecast again starting Tuesday. 37 && .AVIATION... (For the 18z TAFs through 18z Thursday Afternoon) Issued at 1218 PM CDT Wed Jun 19 2024 Scattered diurnal cumulus cloud cover with bases around 4000 ft should be prevalent over the central IL terminals until 01Z. Isolated TSRA possible over the area, although coverage is expected to be low enough that mention in any TAF is not included at this time. The best chances for any more organized thunderstorm activity would be at KPIA around 23Z-02Z, but this activity looks like it will likely remain to the west of KPIA. Winds S-SW 9-13 kts this afternoon, becoming S-SE 3-8 kts by 01Z. 37 && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$