Area Forecast Discussion
Issued by NWS Jackson, KY
Issued by NWS Jackson, KY
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725 FXUS63 KJKL 010835 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 435 AM EDT Thu Oct 1 2026 .KEY MESSAGES... - Temperatures peak later today, while humidity gradually increases heading into the weekend. - A slow moving front will likely bring showers and stray thunderstorms to the area from Friday afternoon into the weekend until a secondary boundary passes through ahead of the new work week. - Dry conditions and below normal temperatures will be the rule through the first half of next week. && .SHORT TERM...(Today through Friday) Issued at 435 AM EDT THU OCT 1 2026 08Z sfc analysis shows high pressure parked east of Kentucky but still in control of the weather for most of the state. This has resulted in another night of mostly clear skies, light wind, and areas of fog in the river valleys - becoming locally dense - but probably not as bad as the past few morning`s. Meanwhile, temperatures currently range from the low 50s in the sheltered northeast valleys to the mid 60s on the ridges. Dewpoints are generally in the mid to upper 50s across the area. The models, and their individual ensemble suites, remain in good agreement aloft through the short term portion of the forecast. They all depict ridging at 5h over the Southeast while a closed trough opens up and spreads east out of the Southern Plains. Through 12Z, Friday the bulk of this system`s mid-level energy lifts north of Kentucky in conjunction with fairly strong troughing pushing east through the northern Great Lakes in the northern stream. Eventually, though, this wave of impulses settle south into Kentucky with height falls for the area and more influence from the weakening vort stream. Given the relatively small model spread, most of the forecast grids again came from unadjusted NBM data this morning. Only limited terrain-based tweaks were made to the temperature grids tonight as more clouds and southwest breezes should keep temperatures more uniform than these past nights - though the deepest valleys will still likely decouple early and drop off significantly. Did also apply a bit of extra drying to the dewpoints this afternoon. As for PoPs, did include the latest CAMs consensus guidance for Friday as the front settles into the area. Sensible weather will feature one more dry and warm day ahead of a cold front slowly pressing south from north of the Ohio River tonight. Look for breezy conditions from mid-morning into the afternoon as temperatures top out in the mid to upper 80s for most spots. Clouds move in more completely late tonight and likely help to moderate the terrain differences by dawn and also mitigate the formation of thicker valley fog. Friday will see the front spread southeast through the day with showers likely and a few embedded thunderstorms possible during the afternoon, though instability will be limited at generally 500 J/kg or less for most places in the afternoon. Training of showers may lead to local excessive rains, but the dry conditions for the past week will limit the overall concern for this potential. With the thick cloud cover and pcpn dropping in from the northwest on Friday, temperatures will be much cooler for highs in the Bluegrass Region - upper 70s - while the southeast half of the area manages to still see the mid 80s. The main changes to the NBM starting point were made to temperatures and dewpoints - adjusted the T grids a bit tonight for terrain details and dewpoints were slightly lowered this afternoon. As for PoPs, included the latest values from the CAMs for Friday`s pcpn chances - moving from northwest to southeast through the area during the day. .LONG TERM...(Friday night through Wednesday) Issued at 345 AM EDT THU OCT 1 2026 The extended portion of the forecast looks to be on track with the idea of northwest flow setting up over the weekend at mid levels, but most impulses staying north and east of our area. This will mean rain chances ending by late in the weekend and drier weather to follow through the start of the new work week. The previous long term discussion follows: The models are in good agreement with more of a split-flow long wave pattern in place across the CONUS at the end of the work week. A progressive short wave trough will start out over the Upper Midwest/Great Lakes on Friday within the northern stream. Meanwhile, a positively tilted southern stream short wave trough will be positioned from the middle Mississippi Valley down through northern Mexico. Ridging will be centered off of the southeastern U.S. coast, while another high is sprawled from portions of the Four Corners region to just offshore of the Southern California coast. Through the weekend, the southern stream positively tilted trough will gradually shift east with time. This feature will then eventually be absorbed into amplifying northern stream energy by early Monday. The northern stream will then hold sway generally east of the Rockies through the middle of next week, with ridging remaining anchored across the West. All of this will result in unsettled weather across eastern Kentucky into the weekend, with cooler and drier weather to follow for the first half of next week. Rain chances will be on the increase from northwest to southeast across eastern Kentucky on Friday, as well above normal PWATs (95th percentile) surge in ahead of an approaching surface cold front. Fortunately, two things are working against the threat of excessive runoff across the area. The first is antecedent dry conditions heading into this event, with most waterways running fairly low. The other will be the instability, as both LREF and NBM probabilities for greater amounts (>500 J/kg) of SB CAPE and MU CAPE have generally been trending down across our area. As such, without better thunder potential, the majority of the higher PWAT air will likely remain untapped. This is also seen in the raw QPF numbers, with probabilities for seeing greater than 1 inch of rainfall in 24 hours ending 8 am Saturday across the area remaining pretty meager from the NBM (10% southeast and 30-40% northwest). As the cold front exits our area Friday evening, widespread shower activity will gradually diminish from northwest to southeast. For Saturday, the better moisture gradient has shifted a bit further into Tennessee this go around, with a larger PoP gradient noted in the blended guidance from northwest to southeast. Mostly cloudy skies will still be in place, with lingering low level northeasterly flow in the wake of the cold front. A secondary surge of moisture will move in for Saturday night and Sunday, with higher PoPs favored across our terrain counties. While a stray thunderstorm can not be completely ruled out, this is also looking less and less likely, given the weaker instability. Cooler progressive surface high pressure will follow Sunday night, moving in from the Plains. This high will shift east with time, settling across the Ohio Valley by Tuesday, before positioning over New England by Wednesday. This will result in dry weather across eastern Kentucky after Sunday. Cooler northeasterly flow will remain in place through Tuesday, with below normal temperatures expected. Highs will average in the 60s and 70s, with overnight lows in the 40s. Some modest return flow ensues by Wednesday, with temperatures returning closer to normal values. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) ISSUED AT 145 AM EDT THU OCT 1 2026 High pressure remains in the vicinity of Eastern Kentucky through the period, leading to VFR conditions at all TAF sites and mostly clear skies. Winds generally remain light out of the south to southwest through the start of the day; however, by mid morning it will become breezy as a 20-25 kt low level jet mixes down with diurnal heating. TAF sites may see gusts out of the southwest as high as 15-20 kt from 14-22Z. && .JKL WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...GREIF LONG TERM...JKL/GREIF AVIATION...GEERTSON/HORTON/GREIF