Area Forecast Discussion
Issued by NWS Jackson, KY
Issued by NWS Jackson, KY
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955 FXUS63 KJKL 091826 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 226 PM EDT Sun Jun 9 2024 .KEY MESSAGES... - A cold front brings rain chances to eastern Kentucky starting early this morning and running through the day. This will end from north to south during the afternoon as the front settles south of the state. - Cooler air will be reinforced across the region early this week, before temperatures modify back to above normal by the end of the period. && .UPDATE... Issued at 200 PM EDT SUN JUN 9 2024 Hourly pops were updated based on radar and satellite trends with convection having moved into portions of the Cumberland Valley near Lake Cumberland while additional convection has developed near the VA border. For now have the highest pops from the Lake Cumberland region to near Black Mountain where the limited instability and moderate shear combination is best ahead of the cold front sagging south across eastern KY. At this point this boundary is near the Mountain Parkway, but will continue south to the TN and VA border into the early evening. UPDATE Issued at 1152 AM EDT SUN JUN 9 2024 A cold front is gradually sagging south of the OH River and into northern portions of eastern KY. Radar and satellite indicated that the front is near the Interstate 64 corridor and gradually slipping south of the interstate. Convection is occurring over portions of western into Central KY while some recent shower development has occurred near Lake Cumberland where cumulus is a bit more agitated ahead of the front. Recent CAM runs have not handled the convection that is working into central KY all that well. The greater instability is forecast to reside southwest and south of the area, with areas nearer to the TN border should have MLCAPE climb to around 500 J/kg or slightly higher with effective shear reaching 30 to 40KT. This could support some organized convection near the TN border and points south and for a time in the afternoon and the track and evolution of convection nearing the I 65 corridor and Bowling Green area will be monitored for possible further refinement of pops. For now areas near and north of the Mtn Parkway will have drier air arriving as the front slips south this afternoon so pops were lowered there. There remains uncertainty on how far south the gradient will need to be though areas right along the TN border will have the best chance for thunderstorms. UPDATE Issued at 735 AM EDT SUN JUN 9 2024 No big changes to the forecast with just the inclusion of the latest obs and trends for the T/Td/Sky grids with this update along with a tweaking of the near term PoPs per the latest radar images. These minor adjustments have been sent to the NDFD and web servers. && .SHORT TERM...(Today through Monday) Issued at 455 AM EDT SUN JUN 9 2024 08Z sfc analysis shows high pressure now off to the east of Kentucky while an area of low pressure is passing off to the northeast. A cold front from this is starting to settle south into Kentucky from the north. At the same time, ahead of this boundary, a healthy cluster of storms is moving into central Tennessee with its northern fringe riding east through south central Kentucky. Thicker clouds have now spread into eastern Kentucky ahead of those southern storms. These clouds kept temperatures more uniform across the area early this morning after we saw a bit more terrain based drop off during the evening. Specifically, readings are generally from the mid 60s to lower 70s. Meanwhile, amid mostly light winds, dewpoints are in the upper 50s to lower and mid 60s. The clouds also have kept most of any fog at bay through the night. The models, and their individual ensemble suites, remain in good agreement aloft through the short term portion of the forecast. They all depict a large 5h low north-northeast of Kentucky dropping through the Ohio Valley and thereby tightening up the northwest mid level flow over the region. Within this flow, an impulse runs through the Tennessee Valley today while a more substantial one pushes south from the Ohio Valley. This latter one brings height falls and keeps more robust packets of energy moving through the JKL CWA into Monday before the 5h trough axis crosses this part of the state by that evening. The model spread continues to be small enough that the NBM was used as the starting point for the short term grids along with the incorporation of the CAMs` details for PoPs today. Sensible weather features a decent chance for showers and a few thunderstorms through the area today, though the highest probabilities for both will be found for the southern half of eastern Kentucky. The southward movement of the cold front will bring an end to the precipitation threat from north to south through the JKL CWA during the afternoon. Only a small sliver of southeast Kentucky will see a chance for showers after 00Z Monday. Drier air, post frontal, will mean more in the way of ridge to valley temperature differences tonight along with a potential for fog in the valleys and places that manage to see the better rain today. For Monday, we will stay dry even though 5h heights will be falling as the northeast trough bottoms out nearby with ample energy flowing above. This will make for rather cloudy skies and cooler than normal afternoon temperatures to start the work week. The main changes to the NBM starting point consisted of adjusting the NBM PoPs to include CAMs details for the shower and storm chances through the day. The temperatures from the NBM were tweaked tonight in order to represent better terrain detail in a drying wx regime. .LONG TERM...(Monday night through Saturday) Issued at 444 AM EDT SUN JUN 9 2024 The extended period will start off with a large trough of low pressure aloft spinning in place over the northeastern CONUS. A north to south elongated narrow ridge of high pressure will be in place from south central Canada southward into the central and southern Plains to start things off. Another trough of low pressure is forecast to be moving across western Canada into central Canada, with weak ridging coming onshore in the Pacific Northwest at the same time. Another system is expected to settle over Florida, and more or less remain in place there through next weekend. As the period progresses, the Plains ridging is forecast to drift eastward and slowly move through the Great Lakes and Ohio and Tennessee Valley regions, bringing dry and warm weather to those areas. In fact, most of the extended should be dry, with a few showers and storms possible along the Virginia border and our far northern counties Friday and Saturday, as troughs of low pressure move by to our south and north. Our next decent chance of rail will likely not arrive until next Sunday, when another area of low pressure moving by to our south pushes just far enough northward to allow isolated to scattered showers and storms to spread into our forecast area from the south. After starting off the period with near normal temperatures in the upper 70s on Tuesday, a major warm up is in store for the remainder of the period. With persistent high pressure in place over the region, we will see a steady northward flux of warm and muggy air off the Gulf of Mexico into the area, which will bring much warmer than normal temperatures into the picture. Daily highs from Wednesday through Sunday look to max out in the mid 80s to lower 90s, as winds shift mainly to the south and southwest, and we experience ample sunshine under mostly clear skies along with strong subsidence warming. With the weather expected to be mostly calm in the extended, there are currently no concerns from any shower or storm activity we experience. With much warmer than normal temperatures expected, heat index values could rise to the point of creating some minor discomfort for anyone engaging in strenuous outdoor activities this coming week, but nothing more. && .AVIATION...(For the 18Z TAFS through 18Z Monday afternoon) ISSUED AT 220 PM EDT SUN JUN 9 2024 A mixture of VFR and MVFR was in place across the region at issuance time with some MVFR in the south ahead of a cold front that has sagged south to near the Mtn Parkway. In addition to the MVFR ceilings in places in the south, some showers and a couple of storms have also developed or moved into areas near Lake Cumberland and the VA border. This activity will move near KSME and KLOZ over the first couple hours of the period and VCTS was used there, though trends take the thunder just south of both locations. After the convection to being the period in the south, improvements to prevailing VFR are expected areawide by about 22Z and there after VFR will largely prevail through the period as the front settles to the south and high pressure noses into eastern KY. A weakening secondary front that sags into the OH Valley and eastern KY later tonight and across the area on Monday should have little affect on the weather. River valley fog is possible in the 04Z to 13Z timeframe, especially where any of the convection occurs over the next few hours. However, this is not expected to affect the TAF sites at this time. Winds will average west and to northwest at generally 10 KT or less for the first 6 hours or so of the period, before becoming light and variable. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...AR AVIATION...JP