


Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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418 FXUS63 KILX 071914 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 214 PM CDT Mon Jul 7 2025 .KEY MESSAGES... - There will be daily chances (20-50% coverage) for scattered showers and storms, particularly during the afternoon and evening hours. There is a marginal risk (level 1 of 5) for severe storms Tuesday across portions of central Illinois. - Seasonable heat and humidity will be in place the remainder of the week into this weekend with afternoon highs generally in the mid to upper 80s and dew points in the 70s. && .DISCUSSION... Issued at 211 PM CDT Mon Jul 7 2025 A weak area of high pressure is centered over the Great Lakes this afternoon with ridging extending into portions of central Illinois. This will help suppress the convective chances for the remainder of today as well as provide brief relief from the muggy conditions across the region with dew points generally running in the 60s north of I-70. Some patchy fog will be possible overnight into Tuesday morning within the weak flow, mainly over east central and southeast Illinois. Surface ridge axis will shift to our east Tuesday allowing humidity to return across central Illinois with dew points building back to around 70 degrees for most of the area. Meanwhile, a shortwave trough is progged to move across the state Tuesday afternoon/evening coinciding with peak heating and allowing scattered thunderstorms to develop. Moderately strong afternoon instability is expected to develop with MLCAPE values advertised by the GFS expected to be around 1500-2000 J/kg. Despite passage of the shortwave trough, deep layer shear will remain sub-optimal for a more organized severe weather threat. Nevertheless, a pulse severe threat will remain a concern Tuesday afternoon and evening with downburst winds the primary concern. Slow storm motions of 15-20 kt from west to east couple with PWats approaching 2 inches will contribute to a localized heavy rain threat. HREF LPMM indicates a couple very isolated pockets of heavy rain (3-5 inches) will be possible. Wednesday and Thursday will be characterized by weak upper level troughing over the Great Lakes region with weak surface ridging over much of the Midwest. Typical summer-time pop-up storms will be possible each day within the weakly forced and modestly unstable environment. Weak deep layer shear and more modest MLCAPE values peaking 750-1250 J/kg both days will keep the severe threat in check, but a brief pulse wind threat cannot be completely ruled out along with slow moving storms that will be capable of locally heavy rain. Friday and Saturday will see a more notable upper wave traverse the northern Great Plains and Upper Midwest. In response to this wave, a warm front will lift across central Illinois Friday. A low level jet developing Friday evening off to our west will allow storms to develop and grow upscale and eventually track east along the warm front into portions of Illinois late in the evening and overnight. A severe threat will likely materialize with this system, and depending on specific timing, could translate east into portions of central Illinois. A cold front sweeping across the region Saturday will result in another round of showers and storms, again with a possible attendant severe threat depending on timing and location of the synoptic front or effective cold front as determined by the remnants of the Friday night storms. Deubelbeiss && .AVIATION... (For the 18z TAFs through 18z Tuesday Afternoon) Issued at 1135 AM CDT Mon Jul 7 2025 VFR conditions persist through the 18z TAF period. Diurnal cumulus will develop with bases around 2k-3kft but will be scattered. Winds shift from northerly to southerly by late tomorrow morning, but the winds stay light (< 5 knots), so only show the shift to easterly at this time. Copple && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$