Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 180741 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 341 AM EDT Mon Sep 18 2017 .SHORT TERM...
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(Today through Tuesday) Issued at 341 AM EDT MON SEP 18 2017 Areas of dense valley fog have developed this morning and much like the past few mornings, will continue past daybreak before burning off by 10 am. As for the rest of the day, mid/upper level ridging will remain in place today, keeping a rather stout cap in place. However, 00z models are showing a bit of a weakening in the cap in our southwest zones (near the I-75 corridor and west) this afternoon. This weakening could coincide with a few isolated showers this afternoon. Confidence is not high on this activity developing as overall forcing will be weak, but could be enough moisture pooling to allow for a few cells to pop up. Any activity will quickly fade away this evening. As skies clear out once more, another night of dense valley fog is anticipated with little change from the current night. Better rain chances will spread in on Tuesday as a mid level vort max crosses the Ohio river valley bringing some height falls. This should help to weaken the cap and provide some weak forcing allow for isolated to scattered showers and storms. No threat for any strong storms as wind shear will remain non-existent under the upper level ridge. .LONG TERM...(Tuesday night through Sunday) Issued at 341 AM EDT MON SEP 18 2017 There is decent model agreement with an amplifying long wave pattern. Deeper troughing establishes itself across the West, with renewed ridging across the Great Lakes and Ohio Valley regions, while the tropics remain active across the western Atlantic and into the Eastern Seaboard. Initially, the ridging in the East will be weaker, allowing for some passing short wave energy to allow for the small threat of mainly diurnally driven showers and a few thunderstorms. For eastern Kentucky, the highest overall POPs for the middle and end of the week look to occur on Wednesday. For Thursday and Friday, some slight chances will be possible along the far south and near the terrain, where enough moisture may pool to allow for a few afternoon and evening pop ups. This weekend, both the GFS and ECMWF show a building ridge across the Great Lakes and Ohio Valley regions. The ECMWF is a little stronger with the ridge, suppressing convection across the area, while the GFS is a bit weaker, allowing for a few storms along the terrain and west of I-75. Given the overall strength of the ridge and predominantly east and northeast flow in the lower atmosphere, will go with a dry forecast. Consequently, went a touch higher than the blended guidance for the highs. Temperatures throughout the period will average above normal, with highs in the low to mid 80s, and lows around 60.
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&& .AVIATION...(For the 06Z TAFS through 06Z Monday night) ISSUED AT 120 AM EDT MON SEP 18 2017 Another night of dense valley fog will be seen in eastern Kentucky with the fog lifting onto some of the ridgetops around daybreak. This is very similar to what we have seen the last several mornings. Visibilities and temperatures are about an hour behind yesterdays pace, so only change was to go about an hour slower with the onset of the fog tonight in the TAFS. Otherwise, expect fog to burn off by 14z again with VFR conditions returning. Fog will be possible again Monday night, with fog developing after 03z, but not impacting TAFS until after 06z. Light winds are expected through the period. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...KAS LONG TERM...GEOGERIAN AVIATION...KAS is the U.S. government's official web portal to all federal, state and local government web resources and services.