Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 180800 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 400 AM EDT Tue Oct 18 2016 .SHORT TERM...
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(Today through Wednesday) Issued at 340 AM EDT TUE OCT 18 2016 Surface Analysis shows high pressure off the east and we are stuck in between surface low across the Northern Midwest. This will establish a gradient across the region today and increasing the LLJ through the day. This will continue to lead to additional WAA and we should see our high temperatures maximized today. That said another potential record setting day with highs in the mid to upper 80s. The previously mentioned LLJ will also combine with decent mixing to lead to gusty winds especially across the Bluegrass and Lake Cumberland region through the afternoon. These winds are expected to subside through the evening as the mixing lessens. Tonight we will begin seeing an increase in clouds across the Bluegrass region as a cold front approaches. This could aid in limiting the temp split tonight, however the usual cold valley spots will see a drop off early on. While the cold front approaches by Wed it does stall out along the Ohio River until the upper level wave moves east out of the plains beyond the short term period. Therefore most spots will remain dry for Wed, but areas mainly north of the I-64 corridor will have a slight chance of a shower and/or thunderstorm in the afternoon. It will remain well above normal for Wed with temperatures topping out in the low to mid 80s. There remains good agreement model wise within the short term, and therefore was comfortable keeping close to the model blends. One issue where straying was needed would be max/min temps. .LONG TERM...(Wednesday night through Monday) Issued at 400 AM EDT TUE OCT 18 2016 The models are in fair agreement aloft through the extended. They do start out well matched up as they move a developing trough through the plains and into the Ohio and Tennessee Valleys by Thursday night. This sharpening wave will push out the upper ridge through the Southeast that has been responsible for the record and near record warmth of the past few days. The trough comes through eastern Kentucky with a potent band of mid level energy late Thursday. For this, the ECMWF is running just a tad faster than the GFS but they are of similar strength. Meanwhile, the Canadian is much too slow and these problems persist through the remainder of the forecast so it has been discounted. Once the core of the trough moves through, the breadth of the lower heights slowly pass through the Ohio Valley into the first part of the weekend before heading into New England - allowing the heights to rebound over Kentucky into the start of the new week. Given the uncertainty around the initial trough moving through the area, but reasonableness of the ECMWF and GFS solutions, the blended guidance looks to be a good starting point. Sensible weather features the best bet for an end to the dry weather so far this month as a healthy cold front will move through Kentucky later thursday with showers and some storms likely. In fact, a few strong to severe storms will be possible given the instability ahead of the boundary and decent upper level dynamics associated with the mid level trough. Will hit this a tad harder in the HWO. The threat for thunder will continue into Friday, but hold to just the higher pops as they depart from west to east during the day. The frontal passage will herald in a colder air mass and with the clearing to follow over the weekend cannot rule out some frost patches for the deeper valleys late at night Friday and Saturday. For now, though, will leave this out of the grids and just monitor its potential in upcoming forecast packages. Made some small to moderate adjustments for lows each night from the CR init throughout the extended primarily to better address anticipated terrain driven ridge to valley temperature splits early and late in the period. As for PoPs, basically just tightened up the highest values around the fropa from Thursday afternoon into Friday.
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&& .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) ISSUED AT 123 AM EDT TUE OCT 18 2016 VFR will be the story through the TAF period. The biggest aviation concern will be the potential for LLWS through dawn, as a SW LLJ creeps into the region from west to east. Then increasing gradient and mixing through the day will lead to gusty SW winds area wide through the late morning into the early evening hours. Wind gust of 20 to 25 knots are not out of the question especially across the Bluegrass and Lake Cumberland regions. While CIGS will remain VFR there is the potential for diurnally driven CU at around 5 KFT and added that thought through the afternoon. The CU and gusty winds will dissipate by the early evening hours. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DJ LONG TERM...GREIF AVIATION...DJ is the U.S. government's official web portal to all federal, state and local government web resources and services.