Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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258 FXUS63 KILX 071750 AFDILX Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 1250 PM CDT Tue May 7 2024 .KEY MESSAGES... - A line of thunderstorms will push into central Illinois early this morning...bringing a few damaging wind gusts to locations west of the I-55 corridor. - Scattered strong to severe thunderstorms will re-develop east of I-55 this afternoon. - Wednesday afternoon severe event is shifting southward...with the latest guidance suggesting the highest probability for damaging winds, large hail, and tornadoes focusing along/south of the I-70 corridor. && .UPDATE... Issued at 1039 AM CDT Tue May 7 2024 Everything appears on track for more storms to develop over parts of the CWA and then move east and northeast this afternoon, with most of the area dry this evening through overnight. HiRes CAMs showing storms developing in northeast parts of the CWA and moving quickly northeast out of the area. Will make some adjustments to the forecast with higher pops in the northeast and keep the chance pops in the CWA for scattered showers and storms. Update will be out shortly . Auten && .SHORT TERM...(Today through Wednesday) Issued at 328 AM CDT Tue May 7 2024 08z/3am regional radar mosaic continues to show a line of strong to severe convection approaching the Mississippi River. The airmass further east across central Illinois has been relatively stable with MLCAPEs of only 100-300J/kg: however, the RAP is showing an uptick to 500-1000J/kg over the next couple of hours as the LLJ transports richer moisture northward into the region. While the line of convection will weaken with time, think it will have enough energy to work with to produce scattered damaging wind gusts along/west of I-55 through 11z/6am. The storms will then continue eastward and will exit into Indiana by mid-morning. After a brief lull in precip chances behind the early morning line, scattered convection will develop by 17z/12pm...primarily east of the Illinois River. Given modest instability characterized by SBCAPEs of around 1500J/kg and very strong 0-6km bulk shear in excess of 60kt, many of the cells will rotate and will be capable of producing damaging wind gusts, large hail, and isolated tornadoes. The primary threat area will be east of I-57 between 12pm and 6pm. After that, the cells will exit into Indiana...leaving behind dry conditions this evening through Wednesday morning. A push of dry air will surge into central Illinois from the west tonight...with both the NAM and GFS showing surface dewpoints dropping to 50-55F everywhere north of I-70 by Wednesday morning. Thanks to this dry air intrusion, the main baroclinic zone will shift slightly further south than previously thought, which will have major implications for the next round of severe convection expected Wednesday afternoon/evening. It now appears low pressure will track eastward out of the Plains along the boundary generally along/near the I-70 corridor. With the strongest instability/shear focused south of the front, the highest probabilities for severe weather will focus from the Ozarks northeastward into the Ohio River Valley. Latest SPC Day 2 Convective Outlook reflects this change, as the Enhanced Risk area has shifted southward to include locations along/south of a Carlinville to Martinsville line. While pockets of strong to severe convection are possible as far north as I-72, widespread severe will likely remain further south where damaging wind gusts greater than 70mph, hail larger than golf balls, and several tornadoes will be possible. Barnes .LONG TERM...(Thursday through Monday) Issued at 328 AM CDT Tue May 7 2024 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 18z TAFs through 18z Wednesday Afternoon) Issued at 1249 PM CDT Tue May 7 2024 Convection is developing quickly over parts of central IL early this afternoon. However, based on HiRes models this will not last very long at any given site. Cloud cover is MVFR with threat of storms...2hrs for PIA, 4hrs for BMI, 2hrs for SPI, 3hrs for DEC, and 4hrs of CMI. After this goes through later this afternoon, clouds will also dissipate/diminish with cirrus or clear skies the remainder of the TAF forecast period. Winds will be breezy today with gusts at all sites up to around 20kts...then diminish into this evening. wind direction will be southerly to southwesterly this afternoon and then remain southwesterly through this evening. Auten && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$