704 FXUS63 KJKL 260609 AFDJKLAREA FORECAST DISCUSSION National Weather Service Jackson KY 209 AM EDT Fri Sep 26 2025
.KEY MESSAGES...
- A daily risk for isolated showers will then continue through the weekend, mainly near the Virginia and Tennessee border.
- The remnants of a tropical system may impact the area for the early part of next week bringing the potential for heavy rainfall.
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.UPDATE... Issued at 1215 AM EDT FRI SEP 26 2025
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 as the shower chances continue to diminish. There will also be a time of fog with locally dense patches around through the rest of the night and early morning, but increasing clouds from the south will likely limit the extent and duration of the fog. These adjustments have been sent to the NDFD and web servers along with a freshening of the zones and SAFs.
UPDATE Issued at 835 PM EDT THU SEP 25 2025
00Z sfc analysis shows low pressure to the northeast of Kentucky with its cold front dragging through far eastern parts of the state. A few showers and even a potential thunderstorm or two are found along and behind this boundary. Drying conditions follow the front later tonight for most of the area though low clouds and areas of fog are also expected. Currently, temperatures are running in the upper 60s to lower 70s. Meanwhile, amid northwest winds of 5 to 10 mph, dewpoints vary from the lower 60s northwest to the lower 70s in the southeast. Have updated the forecast mainly to add in the latest obs and trends for the T/Td/Sky grids but also to fine tune the PoPs and thunder chances through the rest of the night. These adjustments have been sent to the NDFD and web servers along with a freshening of the zones and SAFs.
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.SHORT TERM...(This evening through Friday night) Issued at 234 PM EDT THU SEP 25 2025
Surface analysis across the CONUS is slowly becoming quieter. The synoptic features, mentioned in previous discussions still remain, merely translated a few hundred miles to the east. Locally, a cold front, extending southwest from a surface low over western New York, has passed through the area and is currently impacting West Virginia and Virginia. However, some lingering showers are still developing across the area as the upper-level trough will provide sufficient dynamic forcing for precipitation development through the afternoon.
As mentioned above, the remainder of the day will be characterized by cold FROPA and forcing from a persistent upper-level trough. This trough has been affecting the eastern CONUS for the last several days. Through the day today and into Friday, the trough will pivot overhead but still maintain its positive tilt over the region. As upper-level forcing remains present, showers and isolated thunderstorms will develop through the afternoon before gradually tapering off toward the early overnight. With widespread cloud cover expected this afternoon, high temperatures will only reach the mid- 70s, but where there are breaks in the clouds, a few locations may reach the upper 70s. Cloud cover is expected to remain overhead through the overnight, leading to a mostly mild night with lows only falling into the mid-50s to lower 60s with areas of patchy dense fog.
Friday through the rest of the period will bring similar temperatures, as highs will climb into the mid to upper 70s. However, the highlight from Friday through Saturday will be the cutting off of the trough to form a closed cut-off circulation. Morning and early afternoon model suites consistently show the H5 trough being cut off from the mean flow, with the resultant closed circulation centered over the Central Appalachians. As this occurs, the chances for afternoon showers and thunderstorms will be focused over the southeastern portions of Kentucky. Forecast streamlines of 1000 hPa to 500 hPa RH show the best moisture fetch across those areas as southerly flow is drawing up Gulf moisture. Conversely, northerly flow around the closed circulation will advect drier air into the northwestern portions of the CWA, limiting the potential for afternoon convection in those areas. Any shower or thunderstorm that does develop will quickly taper off toward sunset. Similar to Thursday night, areas of patchy dense fog could develop again for Friday night into Saturday, with overnight lows falling into the mid to upper 50s.
.LONG TERM...(Saturday through Thursday) Issued at 234 PM EDT THU SEP 25 2025
For Saturday, a positive upper trough axis will continue to move slowly into the central and southern Appalachians with the frontal boundary moving well southeast of the area. However, an inverted surface trough will remain across the far eastern sections of east Kentucky.
Shear axis and associated Q-Vector forcing will help keep chances of showers especially areas near the KY/VA and KY/TN state-lines. Ensemble and latest deterministic models show CAPE values of 500 near the KY/VA and KY/TN stateline. These areas will have the greatest chance of scattered showers and possibly a thunderstorm in the afternoon/early evening.
For Sunday, ensemble cluster analysis shows upper trough axis moving east of the area with northerly flow aloft drying the area-mass over the region. More sunshine and mostly dry conditions. Only the far eastern counties have a slight chance of showers.
For early next week (especially Monday and Tuesday), upper trough over the eastern United States becomes a cut-off low over the southeast United States. The evolution of this upper trough/low will play a major role in how the tropical systems affect the central and southern Appalachians. Confidence is low of tropical track and impacts over east Kentucky.
For Wednesday into Thursday of next week, a lot of uncertainties and confidence low in regard to the phasing of the tropical system and remains of weakening upper low over the southeast United States and Appalachians. The ensemble cluster analysis and deterministic models differ a good deal. There is a potential of a good deal of sub- tropical moisture remaining over the area keeping shower activity and cloudy sky. Again, instability remains quite limited at best thus thunder chances are low.
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.AVIATION...(For the 06Z TAFS through 06Z Friday night) ISSUED AT 209 AM EDT FRI SEP 26 2025
Widely varying conditions were noted at TAF issuance. As upper level clouds slowly pull away, expect low clouds and fog to become the prevailing condition at most if not all locations, bringing a period of MVFR/IFR or worse persisting through sunrise. Improvement to VFR can be expected by the late morning/early afternoon hours on Friday. Light winds from the north will be the rule during the period.
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.JKL WATCHES/WARNINGS/ADVISORIES... None.
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UPDATE...GREIF SHORT TERM...VORST LONG TERM...DH AVIATION...GEERTSON
NWS JKL Office Area Forecast Discussion