Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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663 FXUS63 KILX 081742 AFDILX Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 1242 PM 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. && .UPDATE... Issued at 1050 AM CDT Wed May 8 2024 Current forecast is on track, but needed to make some adjustments with the pops/wx grids to account for current thinking. Update will be forthcoming. Auten && .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 18z TAFs through 18z Thursday Afternoon) Issued at 1242 PM CDT Wed May 8 2024 All sites will start as VFR with only mid level cigs seen on satellite for early this afternoon. Cigs will come down to around 5kft as more stratiform rain moves over the sites this afternoon. Only site expected to see thunder will be SPI but will only have as VCTS since storms will be well south of the area. Any lightning in the SPI area will be from high anvil clouds. Other sites should be well north of any lightning. Predominate showers will be seen at PIA and BMI later this afternoon into this evening as a inverted sfc trough rotates through the area. Other sites will have VCSH into the late evening hours, then ending around midnight. Cigs will also drop into MVFR category for later this evening and continue into the overnight hours. In the morning, cigs will drop further...into IFR category with 700-800ft expected. Widely scattered showers may continue during the overnight hours and into the morning, but believe scattered enough to not warrant VCSH or predominate showers on station. Winds will be south to southeast through the afternoon, however, westerly winds are expected tomorrow morning at all sites. Wind speeds will be around 10-12kts at all sites and through the TAF period. Auten && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$