Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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002 FXUS63 KILX 182029 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 329 PM CDT Tue Jun 18 2024 .KEY MESSAGES... - Seasonably hot and humid weather will prevail this week. The hottest conditions will arrive Friday into Saturday when air temperatures climb into the middle to upper 90s and heat index values peak at 100-105 degrees. - 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. && .SHORT TERM...(Tonight through Wednesday Night) Issued at 329 PM CDT Tue Jun 18 2024 Deep-layer moisture continues to flow northward from the western Gulf of Mexico on the back side of a prominent upper high centered over the Carolinas. The corresponding thick cirrus shield has kept temperatures a few degrees cooler than they were yesterday and has limited instability. 20z/3pm satellite imagery shows mostly cloudy skies along/southeast of a Bloomington to Jacksonville line...with sunny skies to the northwest. Cannot rule out a stray shower or storm over the next couple of hours, but areal coverage will remain scant. CAMs are suggesting isolated showers may re-develop overnight across the Wabash River Valley...with showers/storms becoming a bit more numerous further west across Iowa/Missouri in association with a slowing cold front. Overall think most locations will remain dry as low temperatures only drop into the lower to middle 70s. The cold front will become stationary from Iowa into southern Wisconsin/northern Illinois on Wednesday. The strongest forcing and thus the greatest areal coverage of diurnal convection will remain focused just N/NW of the KILX CWA: however, the HRRR continues to suggest widely scattered convection along a pre-frontal trough perhaps as far south as I-72. Have therefore included slight chance PoPs as far S/SE as a Springfield to Paris line...but have focused better rain chances northwest of the Illinois River in closer proximity to the boundary. Otherwise Wednesday will be a hot and humid day with considerably less wind than has been experienced lately. S/SW winds will generally remain in the 10-15mph range as afternoon highs top out in the lower to middle 90s. Barnes .LONG TERM...(Thursday through Next Tuesday) Issued at 329 PM CDT Tue Jun 18 2024 As the upper high retrogrades westward and upper heights rise, rain chances will decrease and temperatures will increase by the end of the week. Latest guidance suggests the hottest period will be Friday and Saturday when high temperatures climb into the middle and perhaps upper 90s in a few spots. Corresponding heat index values will peak at 100-105 degrees...just shy of Heat Advisory Criteria. 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 18 GFS and ECMWF are in relatively good agreement, showing the front arriving Saturday night. As a result, have included high chance to likely PoPs (40-60%) Saturday night into Sunday. Once the front departs, slightly cooler and less humid weather is expected early next week as highs drop back into the upper 80s to around 90 degrees by Monday. Barnes && .AVIATION... (For the 18z TAFs through 18z Wednesday Afternoon) Issued at 1257 PM CDT Tue Jun 18 2024 VFR conditions will prevail through the entire 18z TAF period. Isolated convection will develop across central Illinois this afternoon: however, confidence on a storm impacting any of the terminals is quite low...so have not mentioned thunder at this time. Aside from diurnal Cu at around 4000ft, a thick blanket of high cloudiness will prevail at all sites except KPIA through the afternoon/evening. Winds will initially be S with gusts of around 25kt, then will will decrease to around 10kt after sunset. As a weak cold front approaches from the north, winds will veer to SW at around 10kt by Wednesday morning. Widely scattered convection will develop along/ahead of the front, but should hold off until near or after 18z Wed. Barnes && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$