Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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119 FXUS63 KILX 060813 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 313 AM CDT Mon May 6 2024 .KEY MESSAGES... - A line of convection will push through central Illinois late tonight into Tuesday morning...bringing gusty winds and downpours. - Scattered severe thunderstorms may fire along an outflow boundary along/southeast of a Champaign to Shelbyville line Tuesday afternoon/evening. - Confidence is growing concerning a more significant and widespread severe weather event across much of central and southeast Illinois Wednesday afternoon/evening. && .SHORT TERM...(Today through Tuesday) Issued at 313 AM CDT Mon May 6 2024 A short-wave trough evident on 07z/2am water vapor imagery over southern Missouri will continue lifting northeastward into the Ohio River Valley today. Showers associated with this feature will spread as far northwest as a Bloomington to Jacksonville line: however, precip amounts will be quite light. Instability will remain limited across much of central Illinois, but SBCAPEs increasing to 500-1500J/kg warrants thunder mention along and southeast of a Danville to Taylorville line. Showers will exit into Indiana before sunset as short-wave ridging leads to a period of dry weather this evening into the first half of the overnight. Meanwhile further west, an organized line of convection will develop ahead of a much stronger short-wave crossing the Rockies into the Plains late this afternoon. These storms will push eastward and spill into the Illinois River Valley after 09z/4am. While instability will be waning, think gusty winds and heavy downpours will be a good bet as the line pushes through the western KILX CWA and arrives along the I-55 corridor by dawn. All CAMs suggest the convection will continue eastward and exit into Indiana before midday Tuesday. After that, attention will focus on the exact placement of the residual outflow boundary...which will play a key role in late day thunderstorm development. At this time, it appears the boundary will likely lay out along/near I-70. With a highly unstable/sheared environment to the south across the Ohio River Valley, any cells that form will be capable of damaging wind gusts and large hail. The primary time frame will be from 3pm to 9pm before the storms shift further east out of the area. Barnes .LONG TERM...(Wednesday through Sunday) Issued at 313 AM CDT Mon May 6 2024 After another lull in precip chances Tuesday night into Wednesday morning, all eyes will be on a potential outbreak of severe weather Wednesday afternoon/evening from the Ohio River Valley southwestward into the southern Plains. Low pressure is progged to track eastward out of the Plains into central Illinois...with GEFS mean sea-level pressure suggesting the low will slide along the I-72 corridor during the evening. A highly unstable/sheared environment will once again be in place south of the low track...with GEFS probabilities of exceeding SBCAPEs of 500J/kg and bulk shear of 40kt of 30-40% along I-72 and greater than 80% along/south of I-70. NAM 0-3km VGP values increase to 0.5-0.7, strongly suggesting supercell development along the warm front as well as within the warm sector. As a result, all severe weather hazards will be in play...including damaging wind gusts greater than 60mph, very large hail, and the potential for long-track tornadoes. At this time, the greatest risk for widespread severe weather will be along/south of I-72: however, this area will be fine-tuned as exact details become more defined over the next 24-36 hours. Once the low tracks into Indiana Wednesday night, the severe potential will come to an end and a much cooler/more stable airmass will arrive by the end of the week. High temperatures will be in the 60s while overnight lows drop into the 40s Thursday through Sunday. In addition, periodic shower chances will occur as the Great Lakes/Midwest remains in a northwesterly flow pattern aloft. Barnes && .AVIATION... (For the 06z TAFs through 06z Monday Night) Issued at 1146 PM CDT Sun May 5 2024 An upper level disturbance lifting across southern Illinois late this evening will bring light rain and MVFR ceilings up to near the I-72 corridor. Confidence in rain reaching the terminals remains low but MVFR ceilings appear possible, mainly at SPI. East to southeast winds will prevail through the period. Deubelbeiss && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$