787 FXUS63 KJKL 240850 AFDJKLAREA FORECAST DISCUSSION National Weather Service Jackson KY 450 AM EDT Wed Sep 24 2025
.KEY MESSAGES...
- Multiple rounds of showers and thunderstorms will bring times of soaking rains this week. While beneficial for the drought, this rain could cause localized flash flooding, especially later today.
- A few thunderstorms today could become strong, with damaging wind gusts as the main threat. The potential for these storms will depend on how much the atmosphere can destabilize during the day.
- A wet and unsettled pattern will continue through Friday before cooler and drier, fall-like weather arrives for the weekend.
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.SHORT TERM...(Today through Thursday) Issued at 450 AM EDT WED SEP 24 2025
At 850z, regional radar shows a band of weakening convection lifting over far east Kentucky. This activity is associated with a subtle shortwave perturbation and vorticity maximum aloft, but it is weakening as it moves into an increasingly stable environment. Other disturbances are noted aloft streaming from the parent positively-tilted 500 hPa trough extending from Southern Quebec southwest into the Southern Rockies. These pockets of energy are forcing much of the disorganized convection to our west and southwest over Kentucky and Tennessee. A weak ~1012 mb surface low is developing over northeast Texas ahead of the aforementioned trough and is tracking northeast along a wavy frontal zone stretching to Detroit and then off Cape Cod.
The main story during the short term will be rounds of showers and thunderstorms as the 500 hPa trough translates eastward and the primary surface low tracks northeast today into the Mid- Mississippi Valley, across Kentucky tonight, and into the Northeast U.S. on Thursday. This system will drag the wavy front toward the northwestern portion of the forecast area by Thursday morning. However, that front`s progress will be slowed by another, weaker surface wave developing along the boundary just ahead of the 500 hPa parent trough axis. Thus, passage of the cold front over eastern Kentucky is delayed until Thursday evening. A modest southerly fetch will promote PWATs rising to between 1.6 and 1.9 inches today. This moisture, combined with skinny CAPE profiles (500 to 1500 J/kg of MLCAPE) and a deep warm cloud layer, will be supportive of heavy rainfall rates. Tropospheric flow is strong enough to support progressive cell motions (~25 to 30 kts), which should limit the overall flash flooding threat. However, a nearly unidirectional deep-layer flow parallel to the baroclinic zone to our northwest could aid in training convection. General rainfall amounts of 1 to 2 inches are likely through 12Z Thursday. However, some locales may only receive a few tenths of an inch, while others could see over 3 inches where training occurs. Recent CAM guidance has been consistently generating the highest rainfall totals over the northwestern third of our forecast area, where drought conditions are ongoing, though some models have suggested a second maximum over southeastern Kentucky. The Weather Prediction Center (WPC) has maintained a Slight Risk in their Excessive Rainfall Outlook (ERO) for isolated to scattered flash flooding. Trends will be monitored for any potential need for a Flood Watch. A threat also exists for a few stronger thunderstorms, with gusty winds as the primary concern. Otherwise, looking ahead to Thursday, the better moisture will depart with the exiting low pressure. However, a vorticity lobe in the base of the approaching trough axis and convergence near the cold front will aid in the development of scattered to numerous showers and possible thunderstorms. Dry mid-level air and meager CAPE profiles will tend to limit convective vigor and rainfall rates on Thursday.
In terms of sensible weather, expect rounds of showers and thunderstorms interspersed with breaks of sunshine and periods of dry time. The most widespread shower and thunderstorm activity is expected through midday across all of eastern Kentucky. This afternoon and evening, activity will be most focused in counties along and north of the I-64 corridor. Another widespread round of organized showers and storms can be expected overnight. More sporadic, diurnally-modulated showers and possible thunderstorm activity are anticipated for Thursday. Temperatures will be mild with highs in the mid 70s to near 80 both today and Thursday while overnight lows remain in the 60s.
.LONG TERM...(Thursday through Tuesday) Issued at 241 PM EDT TUE SEP 23 2025
For Thursday, a positive upper trough will move into the area with jet dynamics producing fronto-genetic forcing along an approaching frontal boundary. A band of showers and storms will move across the region producing heavy rains with greatest potential of flooding near the KY/VA and KY/TN statelines. Severe threat is marginal and dependent on any breaks in the cloud to enhance instability. Ensemble composite analysis shows best CAPE/SHEAR across the far south/southeast sections, southward into the Tennessee valley.
For the extended period from Friday through early next week shows a large difference in solutions from the deterministic GFS and ECMWF. Based this period on the Ensemble Cluster Analysis solution which pulls a positive tilted upper trough across the region Friday which becomes quasi-stationary over the southeast/eastern United States.
For Friday, frontal boundary will be east of the area with enough wrap-around moisture to produce a low chance of showers near the KY/VA stateline. Otherwise, plenty of low-level moisture with mostly cloudy sky.
For Saturday, the near stationary trough axis across the eastern United States with wrap-around moisture continuing to produce a chance of showers especially near the KY/VA stateline with sky cover varying from partly cloudy to mostly cloudy. Sky becomes mostly clear Saturday night allowing for good radiational cooling conditions so will modify the mins for the valley/ridge temperature differences.
For Sunday and Monday, upper trough axis remains east/southeast of the area with the region under northerly/northeast flow. Partly cloudy to mostly clear sky with mostly dry conditions anticipated. Ensembles/deterministic models hint at possible inverted surface trough across the area so can not rule out a shower near the KY/VA and KY/TN stateline due to the proximity of the upper trough/wrap- around moisture/limited instability. For Tuesday, persistent and weakening upper trough over the southeast United States. Confidence is too low to include a chance of showers and expect dry conditions.
Sky remains mostly clear to partly cloudy at night allowing for good radiational cooling conditions so will modify the mins for the valley/ridge temperature differences.
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.AVIATION...(For the 06Z TAFS through 06Z Wednesday night) ISSUED AT 202 AM EDT WED SEP 24 2025
Outside of a line of convection crossing the I-75 corridor area (including KLOZ) and fog in some of the deeper valleys, VFR conditions were noted across the area at TAF issuance. As that convective line presses east, deteriorating conditions will follow as shower and thunderstorm coverage increases. Showers and thunderstorms, coupled with low CIGs and poor visibility, will lead to near LIFR, IFR and MVFR conditions for much of the remainder of the period. Generally light, variable winds will become southerly at 5 to 10 kts after sunrise; however, gusty and erratic winds could accompany any thunderstorm.
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.JKL WATCHES/WARNINGS/ADVISORIES... None.
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SHORT TERM...GEERTSON LONG TERM...DH AVIATION...GEERTSON
NWS JKL Office Area Forecast Discussion