Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 140811 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 411 AM EDT Mon Aug 14 2017 .UPDATE... Issued at 1100 PM EDT SUN AUG 13 2017 Despite the incoming thicker high clouds, some of the northeast valleys have cooled to around 64 degrees. As such, did adjust the lows down a few more degrees in places. Elsewhere, low temperatures in the mid to upper 60s look on track, with the higher resolution model still indicating the threat of convection across the area towards dawn. Updates have been sent. UPDATE Issued at 758 PM EDT SUN AUG 13 2017 Mid and high clouds are moving in from the southwest, as moisture is on the increase aloft. Surface moisture is also rebounding, with dew points currently ranging from the lower 60s north of the Mountain Parkway to around 70 in the south. Given the influx of clouds and low level moisture, went ahead and raised lows in the southwest. Will reassess the POPs a bit later this evening, but the overall increase towards dawn looks on target. Updates have been sent. && .SHORT TERM...
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(This evening through Monday night) Issued at 300 PM EDT SUN AUG 13 2017 Dry and pleasant weather will remain in place across eastern Kentucky today and most of tonight, before an area of low pressure finally brings showers and storms back to the area. The latest model data, especially the NAM12 model, is suggesting that showers and storms will move into the forecast a bit sooner than previously thought, and be a bit more widespread. That being said, adjusted the forecast to reflect the latest model guidance. The best chance for showers and storms on Monday will still be during the afternoon hours, with the rain tapering off from northwest to southeast Monday night. The weather system that will produce our rain tomorrow and tomorrow night is forecast to move slowly off to the east. The proximity of this low will allow isolated to scattered showers and storms to linger along the VA and TN borders through late Monday night into early Tuesday morning. As far as rainfall amounts go, the latest NAM guidance is producing the highest totals, which are likely overdone across the forecast area as a whole. Instead adjusted the blended model precip amounts toward the latest NAM amounts, especially along the VA and TN borders for Monday. In general, most locations could see around one quarter of an inch of rain Monday and Monday night, with locally higher amounts possible with any thunderstorms. Temperatures should continue to run slightly below normal during the period. .LONG TERM...(Tuesday night through Sunday) Issued at 407 AM EDT MON AUG 14 2017 Upper level ridging will remain in place across the far SE conus through the extended portion of the forecast. With a deep upper level low across eastern Canada during much of the extended as well, Kentucky will find itself in a troughing pattern, though very deamplified due to the ridging to our south. Several waves are expected to traverse through this longwave pattern and move from west to east across the Commonwealth through the workweek bringing unsettled weather. Models start to diverge in solutions by the weekend, with the ECWMF developing a closed low over the Great Lakes and longwave troughing across the eastern Conus during the day Saturday, while the GFS is much weaker and slower in this development, not impacting the region until Sunday. By Monday they actually come back into agreement with a strengthening ridge building in across the state. At the surface, exiting high pressure to our east will allow for more southerly return flow to make its way into the region for Wednesday. This will interact with a weakening warm front just to our south to produce shower and thunderstorms chances throughout the day, mainly in the southern portion of the state. Meanwhile, a surface low will be located across the central plains and Upper Mississippi River Valley during the day Wednesday, moving northeast and into the Upper Great Lakes by Thursday. This will pull the above mentioned warm front farther northward and elongate it across the state from north to south through the day Thursday without much eastward progression as the parent low slows its movement. The low will pick back up the pace by Friday and continue farther NE, pulling the weakening warm front eastward across the rest of the state and JKL CWA. It still looks as though the warm front becomes a bit washed out by the time it makes it across our CWA, but should still provide good convective potential. A cold front will be close on the heels of the warm front, making it just NE of the Ohio River during the day Friday, and stalling out through the day Saturday. It will finally push southward across the state during the day Sunday, but with little impact. High pressure will take hold for the remainder of the extended as the stationary front remains just to our south. Overall, all this boils down to is unsettled weather through much of the extended, with near normal temperatures but humid conditions thanks to the southerly flow from the Gulf. Best chances for convection will be during the afternoon during peak heating/instability, and best coverage should be during the day Friday as the warm front shifts eastward across the region. The cold frontal passage on Sunday will be quite weak, with generally only isolated convection expected. However the boundary will remain close enough to our south to warrant isolated pops across the far SE for the daytime Monday as well. Otherwise much of the CWA should be clearing with high pressure taking hold.
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&& .AVIATION...(For the 06Z TAFS through 06Z Monday night) ISSUED AT 246 AM EDT MON AUG 14 2017 Mainly VFR conditions prevailed at the start of the period, and aside from localized valley fog in southeast Kentucky, should persist until around dawn. An upper level disturbance passing over is expected to bring showers, mainly on Monday morning, resulting in MVFR conditions for some locations. Most of the showers will taper off by early afternoon, with a return to mostly VFR conditions. However, there is a potential for a few thunderstorms to develop late in the day or in the evening. At this point, there is too much uncertainty to include anything more than VCTS in TAFS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEOGERIAN SHORT TERM...AR LONG TERM...JMW AVIATION...HAL

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