Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 182035 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 435 PM EDT Mon Sep 18 2017 .SHORT TERM...
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(This evening through Tuesday night) Issued at 435 PM EDT MON SEP 18 2017 20z sfc analysis shows weak high pressure in place over eastern Kentucky though it is not effective in suppressing a few showers now popping up over western parts of the Cumberland Valley. On satellite, most of the area is seeing just small patches of cu, but through the breadth of the Cumberland Valley, where the showers are active, the clouds are more extensive and robust. Plenty of sunshine for most of the area have sent temperatures up into the lower 80s. Meanwhile, dewpoints are holding in the low to mid 60s with the winds still light and variable. The models are in fairly good agreement with the recent changes in the mid and upper air patterns through the short term portion of the forecast. They all now are a bit more hearty with the energy that initially drifts through the weakening ridge this evening and then even more so on Tuesday afternoon and evening. This latter batch will lower heights and pool like a small trough between periods of still rather weak ridging into Wednesday morning. Given this agreement have favored a blended model solution along with a good portion of specifics from the higher resolution HRRR and NAM12 and a healthy dose of persistence - especially tonight and early Tuesday morning. Sensible weather will feature some widely scattered showers through early evening - mainly over the western parts of the CWA. a stray thunderstorm cannot be ruled out, as well. Otherwise, it will be more of the same with clearing skies this evening and cooling conditions leading to areas of fog - locally dense in the river valleys for Tuesday morning. Look for the fog to dissipate a bit quicker Tuesday morning as clouds move in from the west ahead of a weak front. This will likely result in showers and thunderstorms developing by early afternoon favoring the western portion of the forecast area. The convection will die out in the evening setting the stage for more fog development that night into Wednesday morning - though limited by more clouds being around through the night. The CONSShort and ShortBlend were used as the starting point of all the grids. Did make some adjustments to the temperature ones each night based on terrain in anticipation of small to moderate ridge/valley splits. As for PoPs, did tweak them for the diurnal cycle peaking late afternoon and diminishing after sunset. .LONG TERM...(Wednesday through Monday) Issued at 306 PM EDT MON SEP 18 2017 An upper level ridge will amplify over the Ohio Valley through the period continuing the unseasonably warm weather pattern for our area. A weak upper trough trapped between Hurricane Jose and the building ridge over the Mississippi Valley will cause the potential for a few showers and storms Wednesday and Thursday. That potential shifts to our southwest and withers as the upper trough dissolves and surface high pressure builds southward ensuring a dry weekend for our region. Temperatures are expected to consistently top out in the low to mid 80s each day through the period. Overnight lows are forecast in the low 60s, then dropping into the upper 50s over the weekend as drier air filters in.
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&& .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) ISSUED AT 240 PM EDT MON SEP 18 2017 After a day and evening of VFR conditions, fog is expected again tonight, with developing commencing after 03z, but not likely impacting TAFS until after 06z. Fog should be similar to the past several nights and be confined mainly to the valleys, but still creep up into a couple of the airport sites for a time. Have used a tempo in a few of the TAFs for this concern. Light winds are expected through the period. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GREIF LONG TERM...ABE AVIATION...KAS/GREIF is the U.S. government's official web portal to all federal, state and local government web resources and services.