Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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874 FXUS63 KILX 182315 AFDILX Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 615 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 00z TAFs through 00z Wednesday Evening) Issued at 615 PM CDT Tue Jun 18 2024 VFR conditions expected the next 24 hours, with ceilings near or above 15,000 feet, primarily tonight. Gusty south winds will begin to diminish early this evening with loss of daytime heating. A gradual shift to the southwest is expected on Wednesday as a cold front approaches the Iowa/Illinois border, but speeds should be near or below 10 knots. Geelhart && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$