Area Forecast Discussion
Issued by NWS Jackson, KY
Issued by NWS Jackson, KY
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219 FXUS63 KJKL 261005 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 605 AM EDT Sat Sep 26 2026 .KEY MESSAGES... - High pressure brings dry and cool early autumn weather into early next week. - Warmer temperatures return from the middle to end of next week, along with our next reasonable potential for rain. && .SHORT TERM...(Today through Sunday) Issued at 545 AM EDT SAT SEP 26 2026 Early this morning, an upper level low was centered east/southeast of the Delmarva with an upper level ridge extending form the western Gulf across the Arklatex region to the Northern Great Lakes. Further west, meanwhile, an upper level trough was working in across portions of the western Conus. In addition, a shortwave trough was moving across portions of the central to northern Plain. With the vertically stacked system off the east coast, the sfc low was also centered east/southeast of the Delmarva. Meanwhile, a ridge of sfc high pressure extended from Ontario across the western and central Great Lakes to the OH Valley and Southern Appalachians. In northwest flow aloft between the upper low to the east and northeast of eastern KY and the ridging to the west, some high to mid level cloud have been passing overhead especially across western portions of the area. Valleys and some lower lying areas have experienced temperatures drop into the mid to upper 40s with low to mid 50s where the clouds have been more prevalent and/or the terrain is more open. Valley fog was evident on satellite and KY Mesonet weather cameras or KYTC weather cameras in portions of the headwaters of the Cumberland, the forks of the KY basin, and the Big Sandy in particular. Some of this looked to be rather dense and an SPS was issued from some of the eastern and southeastern counties until a couple hours after sunrise. Through Sunday, the upper low and sfc system should track in a meandering fashion to near the NYC vicinity with northernly flow remaining across the Commonwealth between this upper low and ridging extending from the Southern Plains/western Gulf into Central potions of the Conus. The axis of the ridging should become established further west as the shortwave in the Plains treks east northeast into Canada and weakens the northern portion of the upper ridging initially in the northern Great Lakes vicinity. Initial valley fog may take as late as 9 to 10 AM to lift and dissipate 2 to 3 hours after sunrise. Overall, surface and upper ridging will keep a rather dry airmass across the region and with the slow moving pattern, temperatures should change little for highs through Sunday with lows Saturday night similar to what occurs this morning. A few high or mid level clouds will pass by from time to time as well. With the dry airmass, PW on the order of 0.25 to 0.45 inches or the 3rd to 12th percentile for this time of year per the 00Z HREF this afternoon and to 0.3 to 0.5 inches or the 7th to 20th percentile on Sunday afternoon also per the 00Z HREF, NBM deterministic dewpoints both afternoons were undercut and trended a bit toward Consshort or recent HRRR runs. With the dry airmass it is probable that it will warm higher than the NBM deterministic in many areas as occurred on Friday and more in line with MOS/ statistical guidance. On average, highs were raised a couple of degrees warmer than the NBM deterministic values while more of a nocturnal valley inversion/ridge/valley split pattern was used for lows compared to the unrealistic more uniform NBM values. .LONG TERM...(Sunday night through Friday) Issued at 514 AM EDT SAT SEP 26 2026 The start of this period is characterized by clear skies and quiet conditions with surface and upper level high pressure dominating. Ridge/valley splits Sunday Night still look likely with lows in the mid 40s in the valleys and low 50s on the ridge tops and some valley fog is also probable. Looking at the nationwide picture, an omega block will be setting up with two upper level lows/troughs near the east and west coasts and ridging/high pressure in the central US. This puts eastern KY in the eastern periphery of the ridging that will migrate east early next week. This will extend the dry and quiet weather until PoPs return mid to late next week. As the ridge moves eastward we will see a return of west to southwesterly flow allowing for a gradual warming trend starting on Monday. This warming will continue, with highs increasing each day until the upper 70s to mid 80s return around Wednesday. That west to southwesterly flow will also allow for increased moisture advection into the OH/TN Valleys, increasing humidity in the latter half of next week. Unsettled weather is set to return with rain chances starting around Thursday. As the previously mentioned ridging moves through and eventually out of the area, the initial western upper level low will start to advance eastward as well. The trough is progged to slow down quite a bit in the central US with a southeast ridge likely being the culprit. Uncertainty exists in the evolution of this pattern and the subsequent rain chances for the region next week. But, the solutions that seems most plausible at this time is that as the core of the upper level slows down in the central US, some subtle shortwaves could eject and move downwind following the contour of the southeast ridge. This would put those shortwaves somewhere in the region starting in the mid-late next week timeframe. NBM and LREF show gradually increasing PoPs with a 50-55% chance of >.01" of rain by Friday. It is important to note that considerable uncertainty exists going into next weekend, but NBM and LREF do show PoPs increasing to 70-80% of >.01" of rain beyond the end of the 7 day period by later Sunday. All in all, we are still on track to see temps increasing daily starting next week, with upper 70s to 80s returning around Wednesday. Low rain chances return as well starting around Thursday and then increase as we go into next weekend. The usual model uncertainties with a forecast this far out makes finer details about next week`s rain chances hard to determine at this time. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) ISSUED AT 235 AM EDT SAT SEP 26 2026 With high pressure in control, valley fog has developed and this should expand in coverage during the first 6 hours of the period, before dissipating by 14Z. This will bring localized IFR or worse conditions, but is still not expected to affect any of the TAF sites. Otherwise, VFR conditions and light winds will hold through the period with passing high clouds from time to time. && .JKL WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...JP LONG TERM...DISINGER/JP AVIATION...GREIF/JP