Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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820 FXUS63 KILX 071949 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 249 PM CDT Fri Jun 7 2024 .KEY MESSAGES... - A decaying thunderstorm complex will arrive late tonight into early Saturday morning...with the highest rain chances (60-90%) focused along/south of a Macomb to Mattoon line. - Near to slightly below normal temperatures will continue for the next several days before the return of summertime warmth with temperatures in the middle to upper 80s by the end of next week. && .SHORT TERM...(Tonight through Saturday) Issued at 248 PM CDT Fri Jun 7 2024 A short-wave trough dropping southeastward across Saskatchewan and Montana is providing the necessary synoptic lift for thunderstorm development across Nebraska this afternoon. 19z/2pm satellite mosaic shows cells blossoming over far southern South Dakota into central Nebraska and these are expected to become more numerous and spread southeastward this evening...eventually aided by a 50-60kt 850mb jet oriented northeastward from the Texas panhandle. The storms will push into Missouri later this evening, then will spill into parts of central Illinois overnight. Most CAMs keep the bulk of the convection just S/SW of the KILX CWA, but bring showers into parts of the area before dawn Saturday. Based on current satellite trends and the 18z HRRR, have focused highest PoPs along/south of a Macomb to Mattoon line from 09z/4am to 15z/10am. Instability will be meager as NAM MUCAPE values remain below 100J/kg. Nevertheless have included slight chance for thunder due to strong LLJ curving northeastward toward central Illinois toward dawn. Once the early morning showers depart into Indiana, mostly dry weather is anticipated for the remainder of Saturday. A weak cold front will push into the area from the northwest, so cannot rule out widely scattered showers/thunder during the afternoon/evening, but think most locations will remain dry. Have held on to chance PoPs south of I-70 into Saturday night as the front settles southward into the Ohio River Valley, but it appears the bulk of the convection associated with the nocturnal jet will occur well S/SW across Missouri into western Kentucky. Barnes .LONG TERM...(Sunday through Next Friday) Issued at 248 PM CDT Fri Jun 7 2024 Cool and predominantly dry weather is expected early next week with highs in the 70s and lows in the 50s Sunday through Tuesday. Coolest night will be Monday night when lows perhaps dip into the upper 40s along/north of the I-74 corridor. After that, upper heights will rise and temperatures will climb back above normal into the middle and upper 80s by next Thursday/Friday. Barnes && .AVIATION... (For the 18z TAFs through 18z Saturday Afternoon) Issued at 1244 PM CDT Fri Jun 7 2024 NW winds will gust 23-28kt for the next few hours before the gusts subside by around 22z. As the pressure gradient relaxes and the atmosphere decouples, winds will become light/variable after sunset...before becoming S and increasing to 10-15kt by Saturday morning. Skies will initially be clear: however, mid-level clouds currently poised upstream across eastern Nebraska/western Iowa will filter into the area this evening. Models continue to show one or more clusters of convection firing across Nebraska during the afternoon, then tracking southeastward and weakening considerably tonight. Most guidance suggests the bulk of the showers will skirt central Illinois to the S/SW late tonight into early Saturday morning. Have added predominant showers at KSPI after 11z and at KDEC after 13z. Have only mentioned VCSH at the remaining terminals. Clouds/visbys will be VFR at the beginning of the event: however, CAMs show ceilings lowering to MVFR at all sites between 11z and 15z Sat. Barnes && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$