872 FXUS63 KJKL 292139 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 539 PM EDT Mon Jun 29 2026 .KEY MESSAGES... - Just a small chance for a stray shower or thunderstorm each day for most of the week. - Heat and humidity build today - likely becoming quite oppressive by mid-week. && .SHORT TERM...(This evening through Tuesday night) Issued at 412 PM EDT MON JUN 29 2026 Substantial ridging will be in place throughout the short term period of the forecast and into the extended period as well. While usually "Big Bubble" means "no trouble" in reference to the upper level ridge, that might not be the case in this instance. As the high builds in from our SE, flow will continue to be SWrly (albeit light) across eastern KY, continuing to advect in warm/moist air and also sinking it at the same time thanks to the strong subsidence. So maybe Big Bubble is changing places with it's evil twin the Heat Dome. Temperatures are forecast to rise into the mid 90s for most locations across eastern KY by Tuesday afternoon (several degrees warmer than today). The additional humidity will make it feel even warmer, with apparent temperatures (heat index) pushing the low 100s. Many places will reach heat advisory criteria again at 105 degrees. Overnight tonight and again Tuesday night will be calm, with the increasing subsidence in place. However, calm doesn't necessarily mean cool. Overnight lows will be mild at best, in the low to mid 70s. Coolest temperatures will likely occur in the deepest valleys, where enough moisture from the streams/rivers may contribute to some valley fog again overnight. Went ahead and issued an Excessive Heat Warning for the western tier or two of counties, where heat indices will be between 100 and 105 degrees across large parts of the county for 4 consecutive days (through at least Thursday). This also lines up with the Louisville office as well. The remaining CWA was placed into a Heat Advisory through the same time frame, matching our other neighboring offices. That being said, there is not a sharp cut off or lowering of temperatures from the warning to the advisory. While some counties will be a few degrees cooler, Pike County, for instance, currently has temperature forecast to get just as high as locations in the Excessive Heat Warning. But it's a starting point, at which we can then upgrade as we move into the following days, or leave as an advisory if things start to trend a few degrees lower. Either way, the messaging here is that there is going to be excessive heat, and going into a large holiday where more people will be spending time outside will make things more dangerous. .LONG TERM...(Wednesday through Monday) Issued at 539 PM EDT MON JUN 29 2026 The long wave pattern will start out amplified and stagnant, characterized by a dominant ridge axis anchored over the central Appalachians, bringing continue hot and muggy weather to the region. This ridge will maintain control through Friday, keeping the weather mostly dry. The ridge will lose its grip by this weekend and into early next week, as enough traversing short wave energy allows for a return of troughiness across the Ohio and Tennessee valleys. Model agreement remains good with the broader pattern, but details become lower confidence towards the end of the extended portion of the forecast. Heat and humidity will be the main weather story through the holiday weekend. The most oppressive days will be Wednesday and Thursday, with high temperatures peaking in the mid to upper 90s, while lows only dip into the lower 70s at night for most locations. Friday will be a shade cooler, with highs in the low to mid 90s, as the core of the upper level ridges shifts off to our east. Highs will continue to lower this weekend, with upper 80s and lower 90s forecast, before cooling further still into the mid to upper 80s by Monday. Unfortunately, the humidity will continue to be high throughout the period, with dew points staying above 70 degrees the majority of the time. While a stray shower or storm will be possible across eastern Kentucky on Thursday, most locations will be rain-free. On Friday, slightly better convective coverage may occur, as the upper level ridge center migrates off to our east, but again, most locations should still be dry. Diurnally driven convection will then increase more in coverage each day this weekend and into early next week. This will occur in response to the transition to the aforementioned troughiness aloft and the eventual approach of a cold front at the surface. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) ISSUED AT 212 PM EDT MON JUN 29 2026 As high pressure continues to set up across the region, subsidence is increasing. That being said, there is still enough lingering moisture and mixing this afternoon to spawn some fair-weather CU across much of eastern KY. A few small showers are also possible near the KSJS TAF in far eastern KY, but should not cause any issues other than a temporary visibility reduction. All CU and any lingering shower chances should dissipate heading into the evening hours with the loss of mixing. This will give way to mostly clear skies overnight, and the potential for some valley fog development. Did not include any fog impacts at the TAF sites at this time. Winds are also light at the TAF issuance, and should remain light through the remainder of the TAF period as well, less than 5 kts. && .JKL WATCHES/WARNINGS/ADVISORIES... Extreme Heat Warning until 8 PM EDT Thursday for KYZ044-050>052- 058>060-068-069-079-080-083>086. Heat Advisory until 8 PM EDT Thursday for KYZ087-088-104-106>120. && $$ SHORT TERM...JMW LONG TERM...JKL AVIATION...JMW