Expires:No;;838851 FXUS63 KILX 081048 AFDILX Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 548 AM CDT Wed May 8 2024 .KEY MESSAGES... - Areas of dense fog along and south of I-70 early this morning. - Severe weather is possible along and south of a Quincy to Danville line this afternoon and evening: however, the highest probabilities for damaging winds, very large hail, and tornadoes will be focused further south from the Ozarks into the lower Ohio River Valley. - Cooler weather is on tap for the end of the week with overnight lows dipping into the 40s Thursday night through Saturday night. && .SHORT TERM...(Today through Thursday) Issued at 329 AM CDT Wed May 8 2024 Drier air advected into central Illinois from the W/SW last evening...resulting in 08z/3am surface dewpoints dropping into the lower to middle 50s everywhere north of I-70. Further south where dewpoints remain in the lower 60s, fog has formed thanks to clearing skies and calm winds. Given lowering visby trends and IR satellite signals suggesting expanding fog, have issued a Dense Fog Advisory for all counties along/south of I-70 through 8am. After the early morning fog dissipates, quiet weather will prevail through midday as attention focuses on an area of low pressure tracking slowly eastward through Missouri. CAMs have consistently shown convection developing near the low across west-central Missouri by mid-morning...with the storms then tracking E/SE along the prevailing baroclinic zone into southern Illinois/western Kentucky. Think this will be the primary severe weather threat this afternoon/evening...and several CAMs suggest it will remain south of the KILX CWA. Given enhanced low-level shear near and north of the stationary frontal boundary, NAM 0-3km VGP values increase to 0.3-0.4 as far north as I-70. As a result, think scattered cells with a risk of damaging wind gusts, large hail, and tornadoes will be possible mainly across the SE CWA between 3pm and 9pm. Further north toward I-72, decreasing instability in the drier airmass will lead to a much lower risk for an isolated strong/severe cell. Widely scattered showers and thunderstorms will remain in the forecast tonight as the low pivots through the region...while the primary severe threat drops further southeastward into the Tennessee River Valley. The low will exit into Indiana on Thursday: however, an upper trough over the Upper Midwest will drop southward toward Illinois by late in the day. Given increasing synoptic lift and ample lingering moisture, showers and a few thunderstorms will be possible as high temperatures drop into the 60s everywhere north of I-70. Barnes .LONG TERM...(Friday through Tuesday) Issued at 329 AM CDT Wed May 8 2024 A series of short-wave troughs dropping southward out of Canada will ensure below normal temperatures and periodic shower chances across central Illinois through Saturday. Highs both Friday and Saturday will remain in the 60s while overnight lows dip into the 40s. As the prevailing upper trough lifts northeastward and heights begin to rise, temperatures will warm back to normal for this time of year in the middle 70s by Sunday...then above normal to around 80 degrees by next Tuesday. Rain chances will increase as well...particularly by the middle of next week as a southwesterly flow pattern tries to establish itself. Barnes && .AVIATION... (For the 12z TAFs through 12z Thursday Morning) Issued at 547 AM CDT Wed May 8 2024 Main aviation forecast challenge will be timing potential convection later today. Latest CAMs continue to focus most of the thunder further south across southern Illinois into the Ohio River Valley, with very little activity into central Illinois. Based on the 06z HRRR/RAP, have opted to include showers with VCTS at KSPI/KDEC between 21z and 02z. Further north, have only mentioned showers at the I-74 terminals after 23z. Low pressure will track through the region this evening and once it passes into Indiana, forecast soundings suggest MVFR to perhaps IFR ceilings developing overnight. Have brought ceilings down to MVFR at KPIA by 03z...then further south to KSPI/KDEC by 08z. Barnes && .ILX WATCHES/WARNINGS/ADVISORIES... Dense Fog Advisory until 8 AM CDT this morning for ILZ062-063- 066>068-071>073. && $$