828 FXUS63 KJKL 080625 AAA AFDJKLAREA FORECAST DISCUSSION...UPDATED National Weather Service Jackson KY 225 AM EDT Wed Oct 8 2025
.KEY MESSAGES...
- It will turn cooler today as a brisk northerly breeze brings in drier air.
- Seasonably cool and dry conditions are expected to continue from this afternoon through the weekend.
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.UPDATE... Issued at 200 AM EDT WED OCT 8 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 and a touch up to the PoPs per the latest radar and CAMs. Did also preserve some trace sprinkles/drizzle through the rest of the night along with areas of fog - locally dense. These adjustments have been sent to the NDFD and web servers along with a freshening of the zones.
UPDATE Issued at 1010 PM EDT TUE OCT 7 2025
With the loss of daytime heating and the passing of a shortwave earlier this evening combined with no lightning having been detected over the past 2 hours in the region, opted to lower thunder chances below 15 percent for the remainder of the night. Otherwise, rounds of showers will continue as a cold front drops across the region through the predawn hours, though chances will linger behind the front with low level flow becoming upslope and moisture lingering. Some stratus build down is also anticipated at times overnight.
UPDATE Issued at 800 PM EDT TUE OCT 7 2025
Hourly grids were updated based on recent observation and radar trends. This led to lowering hourly pops over the next few hours as the main area of prefrontal convection associated with a passing shortwave is exiting into VA. The threat for heavy rain is also ending as the deeper moisture and better forcing will also be pulling out of the area.
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.SHORT TERM...(This evening through Wednesday night) Issued at 345 PM EDT TUE OCT 7 2025
At 19z, the regional radar mosaic shows steady moderate rain occurring across most locations north of the Mountain Parkway with more intermittent rainfall further south. This rainfall is driven by a very moist airmass (PWATs of 1.7 to 1.8 inches) that is feeding into the region on a 30 to 35 kt, 850 hPa jet, then ascending isentropically over a warm frontal boundary and into the favored right-entrance region of an 80+ kt, 300 mb jet streak. That warm front extends from ~Middlesboro northwest to Elizabethtown and into a weak elongated surface low over southern Indiana and western Kentucky. A cold front trails south from the low into Middle Tennessee. A second more potent cold front stretches from the St. Lawrence Valley, across the Eastern Great Lakes, through the Missouri Bootheel and down across Texas. Aloft, there is a 500 hPa trough extending from the Hudson Bay region down into the Mid-Mississippi Valley.
The 300 hPa jet streak will gradually eject northeast through early evening but may also intensify slightly. Thus, while stratiform precipitation is currently diminishing over Central Kentucky, the increased forcing should support an increase in the low-level jet and maintain steadier light to moderate rainfall over northeastern Kentucky until near sunset. South of the Mountain Parkway, activity will remain more showery with the most substantial activity occurring with the cold frontal passage between 4-6 PM in the Lake Cumberland area to around midnight in the far east. Where the steadier rains are most persistent (primarily near and north of the Mountain Parkway), the concern for excessive rainfall continues, potentially leading to urban and small stream flooding. Additional rainfall amounts through the evening could exceed 1 inch and locally approach 2 inches north of the Parkway. Further south, additional rainfall amounts of 0.5 to 1.0 inch are expected. Rainfall, steadier in the north and showery in the south, will taper off with the passage of the cold front.
Behind the first cold front, low stratus, drizzle, and fog are expected overnight as low-level flow turns northerly and upslope. The low-level moisture will linger into the morning hours on Wednesday before gradually sinking southeast as a secondary cold front slides across the area. Clearing skies and drier air will follow that front on a brisk northerly breeze, gusting between 15 and 20 mph at times in the afternoon. As the upper-level trough pulls away, chilly high pressure will build over the Great Lakes on Thursday night. Some nocturnal radiational fog is probable in the more sheltered valleys, but any widespread fog will be mitigated by a subtle northerly gradient flow. Temperatures will drop considerably over the next 36 hours. Tonights lows are forecast to range from the mid-50s in the Bluegrass to the low 60s southeast of the Hal Rogers Parkway. Looking ahead to Wednesday, cool high temperatures are expected, peaking in the upper 60s to low 70s, followed by lows in the low to mid 40s on Wednesday night. A few of the coldest hollows could briefly dip into the upper 30s by around dawn Thursday morning.
.LONG TERM...(Thursday through Tuesday) Issued at 225 PM EDT TUE OCT 7 2025
The period begins Thursday morning with a small yet vigorous disturbance over the Tennessee Valley within overall northwesterly flow aloft between a strong ridge over the center of the country and a deep trough exiting New England. This disturbance digs south to the Southeast coastline and helps to develop a strong surface low along the coast through Monday. Meanwhile, another upper low digs southeast through the Great Lakes into the Mid-Atlantic and combines with the Southeast low to form a large complex low off the Mid- Atlantic coastline. Models are then in good overall agreement in upper ridging building northeastward from the south-central CONUS into the Ohio Valley to end the period Monday into Monday night.
Models continue to trend lower with Friday morning`s low temperatures, especially in the most sheltered northeastern valleys, where some isolated patchy areas of frost cannot be completely be ruled out as temperatures dip into the mid-30s. Otherwise, cool and dry conditions are expected to end this week, this weekend, and early next week, though temperatures will be slowly trending upwards after bottoming out behind the cold front that moves across the area tonight. Any precipitation with the coastal low will remain east of the area through the period.
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.AVIATION...(For the 06Z TAFS through 06Z Wednesday night) ISSUED AT 225 AM EDT WED OCT 8 2025
A range of conditions were reported at issuance time with some locations IFR or lower while others were VFR. There continues to be some uncertainty in conditions to begin the period with patchy rain or upslope drizzle behind a cold front during the early morning hours. Confidence is greater for a general trend of deterioration in ceiling and visibility categories though the first 3-6 hours of the period to widespread IFR or lower with some lingering MVFR followed by widespread IFR or lower area-wide 9 to 12Z. Improvements gradually spread in from northwest to southeast into VFR conditions between 12 and 21Z. During the first 12 or so hours, there should be several hours of near or below airport mins observed at the TAF sites on upslope stratus and drizzle behind the front. Winds will be west and then northwest through 09Z and then finally trend to the north to northeast through the end of the period with speeds of generally 10 kts or less.
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.JKL WATCHES/WARNINGS/ADVISORIES... None.
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UPDATE...GREIF SHORT TERM...GEERTSON LONG TERM...CMC AVIATION...JP/GREIF
NWS JKL Office Area Forecast Discussion