Area Forecast Discussion
Issued by NWS Jackson, KY

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279 FXUS63 KJKL 132019 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 419 PM EDT Sun Jul 13 2025 .KEY MESSAGES...
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- Warm/hot temperatures and high dew points will persist for the next week, resulting in sultry conditions. - There will be a daily potential for showers/thunderstorms over the next week, especially in the afternoon/evening hours.
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&& .SHORT TERM...
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(This evening through Monday night) Issued at 418 PM EDT SUN JUL 13 2025 A modest trough in the prevailing upper level westerlies is crossing eastward over the Great Lakes late today, with a weaker extension further southwest to TX/OK. This is giving us weak southwest flow aloft on the perimeter of subtropical ridging. A seasonally fairly moist atmosphere is present with a tall thin CAPE profile, and showers/thunderstorms have increased in coverage (especially over our southern counties) with diurnal destabilization. Instability and shear combos don`t look favorable for severe wx, and it would probably take strong outflow interaction to have concerns. However, the storms are slow moving and with the CAPE profile they are beginning to show localized hydro concerns. Activity should show a decline this evening with slow loss of instability. However, the weakening upper trough will continue to approach tonight as it becomes increasingly strung out, and additional convection can`t be ruled out. With the last vestiges of the trough still over the area on Monday, and diurnal heating once again, another increase in showers/thunderstorms should occur. The CAPE profile looks similar, without a big concern for severe wx. Flow aloft is forecast to increase a bit with cells moving a little faster, and with that, hydro concerns are a bit less. Activity will once again decline on Monday night, probably to a greater extent due to the demise of the upper trough. .LONG TERM...(Tuesday through Sunday) Issued at 314 PM EDT Sun Jul 13 2025 When the long forecast period opens on Tuesday morning, an upper level ridge will have nudged its way into Southern Kentucky. Thus, Tuesday looks to be the driest day in the long term forecast period, albeit the afternoon hours are still marked by scattered shower/storm chances. After any leftover clouds from Monday`s activity and the AM valley fog burn off, efficient diurnal warming processes should yield notably warmer highs near 90. This exceeds the convective temperature thresholds visible in modeled BUFKIT soundings, but a lack of dynamic support aloft and only marginal amounts of CAPE should limit the impacts of Tuesday`s showers/storms. That activity should begin to subside after sunset and as overnight low temperatures cool down towards 70 degrees. For the rest of the long term forecast period, the guidance suite collectively resolves a stagnant weather pattern over the eastern half of the country. A broad anticyclone is forecast to remain parked over the Southeastern states, whereas zonal flow will move through the Upper Midwest and into the Great Lakes. The Ohio River Valley will be situated between the two, and our sensible weather will accordingly be driven by characteristics of both. Southwesterly flow in the lower levels of the atmosphere will persistently advect a warm, moist airmass into the Commonwealth, keeping temperatures and humidity high. This will lead to above-normal PWATs and increasingly oppressive heat indices on Wednesday and Thursday. Expect afternoon highs in the low 90s on both days and peak heat indices in the upper 90s in the deepest valleys and urban corridors. These warm/humid conditions will combine with some shortwave impulses moving through the broader zonal flow to enhance precipitation chances across the area on Wednesday and Thursday. Thunderstorms will be possible, but they are likely to remain pulse-like in nature. Weak winds aloft and dry air in the column will mitigate deep-layer shear and thus the potential for highly-organized convection. This is particularly true for southern KY, which will be closer to the center of the southeastern ridging. Thus, the greatest sensible weather impacts over the area next week will likely come from the cumulative nature of the heat and the repetitive nature of the precipitation chances. Rain chances will peak every day in the afternoon/evening hours, and the heaviest showers could provide some localized relief from the hot apparent temperatures. However, overnight lows near 70 degrees will provide limited nocturnal relief. The NWS HeatRisk tool has been picking up on the potential for heat-related health impacts across Eastern Kentucky in the Wednesday-Thursday time frame. Likewise, WPC has outlined the forecast area in Marginal (Level 1/4) Excessive Rainfall Outlook on both Wednesday and Thursday. The potential for localized flash flooding will be highest in areas that see multiple rounds of heavy rain multiple days in a row next week, as soils in those places will progressively be able to absorb less moisture. Guidance suggests that the SE ridge may flatten late next week and allow a weak frontal boundary to slide into the forecast area. This could yield slightly cooler afternoon highs in the 80s, but a lack of deep upper level support means that said front is likely to stall out. This will keep diurnally-peaking rain chances in the forecast for next weekend, and we will closely monitor the potential for any potential excessive rainfall-related impacts as the mesoscale details of the forecast become clearer by mid-week. In short, expect an active summertime weather pattern to persist across Eastern Kentucky this week. Confidence is high that Eastern Kentucky will experience seasonably warm/humid conditions and daily diurnal peaks in shower/storm chances throughout the next week. Only minor adjustments were made to the NBM-populated long term forecast grids, as it is capturing the general pattern well. Confidence in the magnitude of overnight ridge-valley temperature splits is low due to the potential for lingering clouds from diurnal convection. Likewise, nocturnal fog may form in locations with wet grounds beyond the typical river valleys. With that being said, grid edits were limited to minor reductions in valley low temperatures, minor increases in ridgetop low temperatures, and the addition of valley fog in the weather grids.
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&& .AVIATION...
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(For the 18Z TAFS through 18Z Monday afternoon) ISSUED AT 418 PM EDT SUN JUL 13 2025 Scattered showers/thunderstorms were ongoing at TAF issuance, mainly in our southern counties, and were bringing localized sub- VFR conditions. Otherwise, conditions were VFR. This scenario will persist into the evening, but an overall decrease in activity is expected. Late tonight, fog development is forecast, especially in valley locations which received rain. This will bring localized IFR or worse conditions. Fog will dissipate on Monday morning. Another increase in showers/thunderstorms should occur on Monday after diurnal heating/destabilization kicks in.
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&& .JKL WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...HAL LONG TERM...MARCUS AVIATION...HAL