FXUS63 KJKL 240820 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 420 AM EDT Mon Aug 24 2026 .KEY MESSAGES... - Noticeably less humid air prevails early this week, with below normal morning low temperatures. - Temperatures and humidity will increase Wednesday and Thursday ahead of the next cold front, leading to a potential for storms. && .SHORT TERM...(Today through Tuesday) Issued at 420 AM EDT MON AUG 24 2026 07Z sfc analysis shows high pressure over the Ohio Valley - dominating the weather for Kentucky this night. This has meant mostly clear skies, light to calm winds, and good radiational cooling conditions. As such, areas of fog developed in the river valleys and they have become locally dense. In addition, a small ridge to valley temperature difference showed up with readings ranging from the upper 50s in the lower sheltered spots to the low and mid 60s on top of the hills. Meanwhile, dewpoints were generally in the upper 50s to lower 60s. The models, and their individual ensemble suites, are in good agreement aloft through the short term portion of the forecast. They all depict a deep closed low 5h tough over the eastern Great Lakes while stout ridging is noted over the land of enchantment state and western Texas. This places eastern Kentucky on the southwest edge of the northeast trough - a location that keeps a steady stream of air running from northwest to southeast overhead at mid levels. The trough will fill and lift northeast through the start of the week allowing the northwest flow to slow a bit with time while any energy passing through is mostly unconsolidated and benign - a far cry from those that spawned the MCS activity of the past couple of weeks. Only late in the period do we start to see a minor trough develop over the western Great Lakes with a potential impact for our area later in the week. On account of the relatively small spread in the models' solutions for the overall pattern aloft, the unadjusted NBM data was used for the bulk of the grids for this forecast package. However, some enhancements were made to the afternoon dew points and terrain differences at night given the drier air mass in place. PoPs were left near zero through Tuesday evening. Sensible weather each day will feature terrific conditions with comfortable afternoon humidity levels and ample sunshine once the early morning valley fog clears. Temperatures will be on the cool side today and near normal for Tuesday. At night, look for valley fog developing and those valleys to run a few degrees cooler than ridge tops under mostly clear skies and seasonably cool low temperatures. The main adjustments to the NBM starting point were to include the impacts of radiational cooling at night for terrain distinction and also some dry air available to mixdown each afternoon - lowering dewpoints and RH. Little opportunity to improve PoPs or QPF was noted through Tuesday evening. .LONG TERM...(Tuesday night through Sunday) Issued at 345 AM EDT MON AUG 24 2026 As the long term period opens, a high amplitude upper level ridge will sit over the western CONUS, with troughing in the East. Within this broader troughing, a relatively vertically stacked closed low will be located over Ontario, on the eastern periphery of the upper level ridge. At the surface, a cold front will extend to the southwest of this low (roughly draped from the Upper Midwest into the Great Plains). As this low progresses to the southeast with time, the upper level trough axis will also progress east. A broad area of height falls is expected across the Ohio Valley, intensified by a shortwave that may approach the forecast area around Wednesday afternoon/evening. Concurrently, another surface low originally over the Southern Plains will translate to the northeast, with a warm front lifting north toward Tennessee. Although southwesterly winds should allow for very modest moisture return for the forecast area on Wednesday, the best chances for rain during the day will be closer to the vicinity of the front and the low, well southwest of the forecast area. Thus, the forecast area should remain relatively dry during the day on Wednesday, with warmer weather than in previous days. Highs will rise into the mid to upper 80s, marking a return to average to slightly above average temperatures, and with dewpoints rising back into the 60s, it will feel more humid, too. Following a relatively quiet day, rain chances will tick up again Wednesday night into Thursday as the aforementioned Canadian low translates eastward and its cold front approaches the forecast area. Scattered showers and storms will be possible ahead of this boundary, although with shear remaining weak (with effective shear in the neighborhood of 20-25 kts), more robust storm organization will be lacking. With the parent low so far north, frontal forcing will also be relatively weak, with a barely perceptible temperature and moisture gradient along the frontal boundary by the time it approaches eastern Kentucky. These factors will keep convective coverage scattered overnight Wednesday through Thursday. By Friday, the cold front will have cleared the area, marking a return to a drier pattern. The upper level trough axis will be east of the area; meanwhile, the upper level ridge will have expanded eastward somewhat, with height rises across the forecast area and flow becoming increasingly zonal aloft as the trough lifts northward. Given this pattern, temperatures will likely be above average through the duration of the period, with forecast highs generally in the mid to upper 80s. An isolated shower or storm will be possible in far eastern Kentucky on Friday afternoon where the ridging influence is the weakest; otherwise, rain chances will remain low for the duration of the period, with the most notable weather being typical valley fog formation overnight. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) ISSUED AT 140 AM EDT MON AUG 24 2026 Valley fog will spread early this morning bringing localized IFR or worse conditions, probably affecting the KLOZ and KSME TAF sites for a brief time around dawn. Otherwise, VFR conditions are expected through the period along with light and variable winds. && .JKL WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...GREIF LONG TERM...FAGAN AVIATION...HAL/GREIF