FXUS63 KJKL 081200 AAA AFDJKL AREA FORECAST DISCUSSION...UPDATED National Weather Service Jackson KY 800 AM EDT Wed Jul 8 2026 .KEY MESSAGES... - Locally dense fog will affect much of the area through the morning commute. - Warm and humid weather will persist through the week. - There is a good chance of showers and thunderstorms into the weekend, especially during the afternoon and evening hours. - Locally heavy rainfall will be a possibility through the next 7 days, with a threat of at least isolated flash flooding each day. && .UPDATE... Issued at 725 AM EDT WED JUL 8 2026 Almost a repeat of yesterday morning with a need for a Dense Fog Advisory, though it seems to be lifting to a stratus so may not be as much of a concern for valleys now. Otherwise, no significant changes were made to the forecast with mainly just the inclusion of the latest obs and trends for the T/Td/Sky grids. These tweaks have been sent to the NDFD and web servers along with a freshening of the zones. && .SHORT TERM...(Today through Thursday) Issued at 445 AM EDT WED JUL 8 2026 08Z sfc analysis still shows a weak and ill defined pressure pattern over eastern Kentucky. This is allowing the diurnal cycle to be the main driver of the weather. At night, the convection dies off along with much of the clouds allowing very limited radiation cooling and the development of fog - becoming dense in the valleys. Again due to high humidity there is minimal terrain differences showing up in the temperatures. Specifically, readings are generally in the upper 60s to lower 70s with similar dewpoints, amid light to calm winds. An SPS is again in effect for areas of dense fog early this morning across the entirety of the JKL CWA. The models, and their individual ensemble suites, remain in good agreement aloft through the short term portion of the forecast even as they indicate more amplification to end the work week. Initially, they all depict a positively tilted 5h trough in place over the Tennessee Valley through western Kentucky. This trough will fill and dampen through Thursday as it slowly drifts east with very small height falls for the area. Late in the period the westerlies at mid-level running through the northern Ohio Valley start to speed up and settle south toward Kentucky. This essentially sets the stage for additional short waves - some probably convectively induced from upstream - to impact the area into the start of the weekend. Given the good enough agreement among the models through 00Z Friday, the NBM was used as the starting point for the grids with some adjustment applied for very minor terrain details in temperatures tonight. As for PoPs, consensus guidance for convective timing and coverage were included from the latest CAM runs. These were again smoothed and fitted to a reasonable diurnal trend - though with more influence from mid and upper level dynamics possibly extending the convection later into the nights than the past couple of them. Sensible weather features typical summertime conditions stuck on repeat as conditions will be warm and humid with mainly afternoon and evening convection. Overlaid on this fairly predictable pattern will be the potential for outside influence in the form of waves at mid level working into or near the JKL CWA - particularly on Thursday and beyond. Slow storm motions and high PWS (at times over 2 inches) in place means a heightened concern for localized flooding - especially for places that see training cells - becoming cumulative by week's end with isolated flood concerns peaking. In addition to the excessive rain, we will also need to be on the look out for organized convection from those strengthening and nearing westerlies bringing perturbances closer to the area such that damaging wind gusts could be possible from any more organized storms Thursday afternoon and evening - especially over our western zones. The main adjustments to the NBM starting point were to include more high resolution CAMs details (smoothed) into the PoPs and thunder potential grids through Thursday evening. .LONG TERM...(Thursday night through Tuesday) Issued at 345 AM EDT WED JUL 8 2026 The main change to the grids for the first part of the extended forecast this morning was to adjust spot specific Max and Min temps at several points though the area. Faster flow at mid levels and general troughing over the Ohio Valley will continue into the weekend and likely support an enhanced threat for heavy rain and localized flooding - particularly Friday and Saturday. The previous long term discussion follows: Thursday, a positively tilted trough featuring an area of low pressure is modeled over the IN/IL/KY area. A secondary upper level disturbance is also modeled over the Iowa area. Further west, an area of high pressure remains of the southern California coast. Heading into Friday the secondary low over Iowa moves into the Ohio Valley, while ridging amplifies over the western US. Late Friday evening a third disturbance over the Rockies will spill into the Plains and eventually into the Ohio and Tennessee Valley by Saturday, as high pressure continues to build into a 598-dm heat dome over the Intermountain West. For sensible weather in Eastern Kentucky, scattered showers and thunderstorms will be possible through Monday, with chances slowly diminishing behind a cold frontal passage Sunday. Model PWATs generally remain above 1.75 inches through a good portion of the period but peak Friday evening into Saturday morning. Those PWATs range anywhere from 2.0-2.1 inches, and according to the ECMWF Mean PWAT, the values fall within the 90th percentile of climatological normals. Given the abnormal PWAT, recent rainfall, and potential to exceed flood guidance with any good storm with the potential for producing torrential rain, the WPC has placed all of Eastern Kentucky in a Marginal Risk on Thursday, and a Slight Risk for Excessive Rainfall both Friday and Saturday. Tuesday, rising heights will lead to warming temperatures as multiple models show a 600-dm high over much of the Northern and Central Plains. One can expect mostly sunny skies and dry conditions. Temperatures warm into the low to mid 80s through Sunday, with lows cooling into the upper 60s. With high pressure building into the area Monday and beyond, temperatures may be a few degrees warmer into the mid to upper 80s. Otherwise temperatures cool into the upper 60s. && .AVIATION...(For the 12Z TAFS through 12Z Thursday morning) ISSUED AT 800 AM EDT WED JUL 8 2026 The fog and low stratus are affecting the majority of the TAF sites at the 12Z issuance with VLIFR conditions reported. This is expected to possibly convert to or merge with a low cloud deck before clearing out. VFR conditions then return until more showers/ thunderstorms develop after daytime heating builds. This once again results in localized IFR or worse conditions likely lingering later into the evening than the past couple of nights. Winds will be light and variable away from any storm. && .JKL WATCHES/WARNINGS/ADVISORIES... Dense Fog Advisory until 9 AM EDT this morning for KYZ044- 050>052-058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...GREIF SHORT TERM...GREIF LONG TERM...GINNICK AVIATION...GREIF