####018004915#### FXUS63 KILX 162311 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 611 PM CDT Thu Jul 16 2026 .KEY MESSAGES... - Persistent heat and humidity will continue to build through Saturday. Heat indices peak around 100F today and tomorrow and 100-105F Saturday. - Isolated to widely scattered thunderstorms (20-40% coverage) are possible today and tomorrow, mainly during the afternoon and evening hours. Locally heavy rain is the primary concern. - A cold front brings a potential for strong to severe thunderstorms Saturday afternoon and evening. && .DISCUSSION... Issued at 126 PM CDT Thu Jul 16 2026 Synoptic Overview... This afternoon, surface analysis reveals a split high-pressure regime with centers located over the Great Lakes and the lower Mississippi Valley. A neutral point lies between these two features across central Illinois. Aloft, a robust 590 dam high is anchored over the Desert Southwest, establishing a persistent northwest flow downstream across the Great Lakes region. Heat and Humidity... Near-term concerns focus on persistent heat and humidity. An 850mb thermal ridge, currently observed near 25C over the northern Great Plains, is progged to drift eastward across the Upper Midwest on Friday before settling over central Illinois on Saturday, where temperatures aloft will ease slightly to around 20C. Daytime highs will remain near 90F today and tomorrow then into the low 90s Saturday under the thermal ridge axis. Given dew points in the lower to mid-70s, heat indices are expected to peak between 100-105F Saturday afternoon. Convective Outlook... For today and Friday, moderate instability with MLCAPE values around 1500 J/kg will be present. In the absence of large-scale forcing and with weak deep-layer shear (<15kt), the severe threat remains low. However, isolated to widely scattered thunderstorms will be possible during peak heating under weakly or uncapped conditions. Slow storm motions of less than 15 mph present a risk for localized heavy rain; HREF LPMM guidance suggests potential for rainfall totals in excess of 2 inches. In addition, non-supercell tornado parameter values around 1 are currently observed within the area of ongoing developing convection south of I-72 suggesting a few brief funnel clouds may be possible. Saturday, a robust shortwave trough is expected to dig across the Great Lakes, driving an attendant surface cold front south across central Illinois. This boundary will interact with strong instability, with MLCAPE progged to exceed 3000 J/kg. While deep-layer shear remains marginal (20-25kt), the timing of the front appears favorable for peak diurnal heating, potentially supporting stronger storm development Saturday afternoon and evening. Extended Forecast... Surface high pressure builds over the Great Lakes on Sunday behind the departing cold front, providing a brief window of near-normal conditions with highs in the mid-80s. The frontal boundary is expected to lift north across the region on Monday. While placement uncertainty exists at this range, a strengthening low-level jet could drive a nocturnal MCS along the boundary Monday evening and overnight. By mid-week, a stronger Canadian high will build south across the northern Great Plains and Upper Midwest, ushering in drier, slightly below-normal conditions for the latter half of the week. Wildfire Smoke... Canadian and Upper Midwest wildfire activity continues to produce a considerable smoke plume across the Great Lakes into New England. Current HRRR near-surface smoke guidance indicates the southern edge of this plume may graze the I-74 corridor tonight before shifting north on Friday. While confidence in significant local impacts remains low, we will monitor trends closely to determine if current Air Quality Alerts need to be expanded southward. A secondary, more favorable window for smoke advection into central Illinois appears possible Saturday behind the passing cold front, though guidance suggests this may be in a lower concentration than is currently being observed to our north today. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 611 PM CDT Thu Jul 16 2026 Scattered showers from KSPI-KCMI southward will fade as sunset approaches. More numerous showers/storms are expected to develop beginning early Friday afternoon, and will include a PROB30 at all terminals for this potential. VFR conditions expected to prevail, though some brief lower visibilities will accompany the stronger storms. && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$ KEY MESSAGES...Deubelbeiss DISCUSSION...Deubelbeiss AVIATION...Geelhart ####018004712#### FXUS64 KOHX 162313 AFDOHX Area Forecast Discussion National Weather Service Nashville TN 613 PM CDT Thu Jul 16 2026 ...New UPDATE, AVIATION... .KEY MESSAGES... Updated at 603 PM CDT Thu Jul 16 2026 - Daily rounds of storms will continue through the weekend. Strong winds gusts and heavy rain causing localized flooding are possible in stronger storms. - Temperatures will warm with heat indices in the low-100s west of the Plateau Friday into early next week. - Tuesday will be the hottest day of the period with heat indices nearing or exceeding 105 degrees for most of the area. && .UPDATE... Issued at 603 PM CDT Thu Jul 16 2026 Another day, another crop of showers and thunderstorms. Isolated showers are still ongoing at this hour, but today's activity hasn't been that impressive with only a little lightning produced. This activity will wane once the sun sets, giving us a mainly quiet night. Fog will once again be a concern though, particularly for areas that have received rain today. Look for additional showers & storms to develop by tomorrow afternoon with the typical summertime hazards of lightning and brief heavy rain. && .SHORT TERM... (Rest of today through Friday) Issued at 1108 AM CDT Thu Jul 16 2026 Largely a persistence forecast is underway for Middle Tennessee. Weak synoptic forcing coupled with high moisture content (PWATs around 2 inches, above the 90th percentile for mid July) has sparked typical summertime convection. These are very slow-moving showers and storms due to the weak steering flow, so localized flooding will be a risk with any heavy downpours. Temperatures will hold steady near normal today, but be on the lookout for a warmer pattern change starting Friday. As a 594 dam midlevel ridge starts to encroach on the southeastern CONUS Friday afternoon, temperatures begin their slow climb. && .LONG TERM... (Friday Night through next Thursday) Issued at 1108 AM CDT Thu Jul 16 2026 We should stay below Heat Advisory criteria (heat index of 105F+) through the weekend, but will start seeing more frequent heat indices in the triple digits. PoPs are also on the rise this weekend as a result of a few shortwave systems embedded in the main flow. A more noteworthy feature is forecast to sweep through Saturday evening, bringing a wave of showers and perhaps a few stronger thunderstorms through Middle Tennessee. Initial look at the parameter space indicates a very weakly sheared environment, suggesting our primary threat will be damaging winds on the storms' outflows. Lapse rates look quite poor (around 5 degC/km), mitigating the hail threat. Much of the area will see some type of precipitation as this feature moves through late Saturday night, but the bulk of the severe weather threat will be confined to areas along and east of I-24. The hottest day of the forecast period certainly looks to be Tuesday; midlevel ridging combined with an approaching frontal boundary at the surface will most likely cause muggy air to pool along the south side of the front on Tuesday afternoon. This will lead to dangerous heat and humidity sending heat indices at or above 105 degrees on Tuesday, so we will be monitoring the need for heat headlines. After this front passes, temperatures finally return to near normal in the upper 80s for the remainder of the week. && .AVIATION... (00Z TAFS) Issued at 603 PM CDT Thu Jul 16 2026 Isolated showers & storms will diminish around 01Z. Light southwest winds will continue overnight with patchy fog developing, resulting in MVFR to IFR conditions. Highest confidence in fog impacts are at SRB and CSV. Any fog that does develop will diminish between 12Z and 14Z. Another round of isolated to scattered showers & storms will develop by early Friday afternoon and introduced PROB30 groups for each terminal. && .PRELIMINARY POINT TEMPS/POPS... Nashville 74 90 74 91 / 10 60 20 50 Clarksville 73 89 74 91 / 20 50 10 40 Crossville 70 85 69 84 / 20 60 20 80 Columbia 72 90 72 91 / 10 60 20 50 Cookeville 72 86 71 86 / 20 50 40 80 Jamestown 71 86 70 85 / 20 60 30 80 Lawrenceburg 71 88 71 89 / 10 70 20 60 Murfreesboro 73 90 73 91 / 10 70 30 70 Waverly 72 89 73 90 / 10 50 10 30 && .OHX WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE.......Clements SHORT TERM...Dirkes LONG TERM....Dirkes AVIATION.....Clements ####018003874#### FXUS63 KTOP 162314 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 614 PM CDT Thu Jul 16 2026 .KEY MESSAGES... - Temperatures continue to warm into the upper 90s, near 100 degrees this weekend into early next week. Dangerous heat is of concern as heat indices up to 105 are probable over east central Kansas. - Widely scattered sub-severe storms are expected this afternoon (20-40%), mainly over portions of east central and far northern Kansas. Brief downpours and lightning are the main hazards. - A weak frontal boundary moves into the region next week, signaling increased precipitation chances. Lack of deep moisture however lends to low confidence at this time. && .DISCUSSION... Issued at 153 PM CDT Thu Jul 16 2026 Similar upper air pattern in place this afternoon with the cutoff low bringing very heavy rainfall to south Texas while the ridge dominates much of the CONUS region. Subtle embedded perturbations are noted lifting north and west towards northeast Kansas, providing enough lift amid no inhibition for widely scattered storms to develop between 2 and 8 PM this evening. Other than the threat for lightning and brief, heavy downpours, severe storms are not anticipated given the weak wind shear in place. Additional widely scattered storms may redevelop once again Friday, however latest guidance trends focus the shortwave trough over southern Kansas during peak heating. Lingering cloud cover throughout the day Friday may also limit temperatures to near 90 degrees. Warming temperatures become the primary hazard of the forecast as the upper ridge currently over the Rockies shifts eastward this weekend. Warm low level advection increases as H85 temps are consistent among models from 23-26C, mixing down to the sfc by late afternoon. There may be little relief overnight as forecast lows are in the 70s. Dewpoints are more uncertain with a high spread noted in the NBM 25th-75th percentiles. If we mix down additional drier air, our temperatures will be warmer whereas higher dewpoints also result in higher heat indices. Based on the current setup as the ridge sticks around through early next week, we may need to consider heat headlines for possibly Sunday, but especially on Monday where peak heat indices reach around 105 in portions of east central Kansas. Upper trough digs into the northeast CONUS on Tuesday, shunting the ridge southward and transitioning flow aloft to the northwest. A weak frontal boundary is progged to sink south into the region in the Tuesday-Wednesday timeframe with operational models developing low QPF along the front. Model ensembles however are trending drier as 6 hr QPF probabilities of at least 0.01 or 20% or less. Even though the moisture availability is scarce, mostly cloudy skies and cooler, north winds drop highs back to near normal values in the low 90s. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 612 PM CDT Thu Jul 16 2026 Afternoon showers and storms continue to diminish in coverage and generally decay over the next hour. Expect that SCT mid clouds remain into the evening and part of the overnight. Winds veer to the SSW into the morning tomorrow with FEW low-level clouds in the BL. Any fog potential overnight looks too low to mention with partial mixing in the BL with winds slightly stronger just off the surface. If any fog is able to form as clouds clear into the sunrise time frame then would expect any ground fog to be very shallow but could be slightly deeper at TOP due to moisture from the recent brief storm. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Prieto AVIATION...Drake