Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 190900 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 500 AM EDT Wed Oct 19 2016 .SHORT TERM...
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(Today through Thursday) Issued at 345 AM EDT WED OCT 19 2016 Morning surface analysis showing a surface cold front and weak low pressure to our NW nearing the Ohio River Valley region. This boundary will remain quasi stationary today and we will see clouds and showers ride along and just ahead of the boundary. That said CAMS generally keep best chances of POPs along and north of the I-64 corridor. This seems reasonable given boundary placement and general forecast progs. That said keep best coverage of clouds across the far NW and therefore the lower overall afternoon highs. Now while the high temps may not exceed the records from 2005 particularly at JKL, we will remain well above normal today areawide. Tonight the frontal boundary will begin to start moving toward the eastern KY, as upper level trough begins to deepen across the plains. This will begin to bring additional clouds toward dawn and slight POPs in the western portions of the CWA toward dawn. These additional clouds will aid in limiting the ridge/valley temp splits. Thursday the upper level trough will continue to deepen across the Mid Mississippi River Valley. This will aid in deepening a surface low pressure and swing a frontal boundary toward the eastern KY for Thursday afternoon. This will bring widespread much needed rainfall to the region, as deep layer moisture progresses across the region with PWATs greater than 1 inch. The next issue will be the marginal chance for a strong to severe storm across the region. This as unidirectional bulk shear increases to around 40 knots and modest destabilization occurs through the afternoon. The destabilization is one of the bigger concerns, as cloud cover ahead of this system could limit destabilization. Therefore marginal severe setup with gusty winds being primary threat seems reasonable at this point. Given some mid level dry air and if we can get low level lapse rates approaching 7 to 8 c/km, as seen in some of the model soundings. .LONG TERM...(Thursday night through Tuesday) Issued at 500 AM EDT WED OCT 19 2016 The models are in somewhat better agreement aloft with the main features passing through the area for the extended. The first, and most prominent, of these will be a fairly strong trough plowing through the Ohio and Tennessee Valleys Thursday night into Friday. The CMC has moved significantly toward the others` consensus with now the ECMWF and NAM lagging the GFS - increasing confidence in the consensus solution. The core of the energy with this system will pass through the area midday Friday before moving to the East Coast to fuel an early season Nor`easter. Heights will be slow to rebound in the wake of this wave as it deepens and spins slowly away into the Mid Atlantic States by Saturday. Some trailing energy will stream over East Kentucky to start the weekend, but for the most part the activity will stay north and east of the JKL CWA well into the new work week. This is primarily due to strong ridging reasserting itself to the south and shoving higher heights into the Tennessee Valley and Kentucky through mid week. Given the better model agreement - a blended solution looks to be a good starting point for the forecast. Sensible weather will feature a potent cold front working through eastern Kentucky Thursday night with a sharp change in air mass and the best shot of meaningful rain in weeks. Expect some ongoing thunderstorms at sunset Thursday to quickly diminish as they work east with the front that night. Plenty of light to moderate rain will follow into Friday - slowest to clear the far east due to the moisture and cyclonic flow associated with the East Coast development. A question that remains in the models concerns the absorption of the low pressure and moisture of a potential tropical system off the southeast coast. Should this get sucked in quicker than implied currently, we would look for a bit more in the way of rainfall across the eastern tip of the CWA along with a slower departure late Friday. As it stands, this front and its associated moisture look to be the best bet for much needed soaking rains. High pressure in its wake will make for dry and cool conditions slowly moderating back to normal temperatures through the start of the new week while the storm track stays well north of Kentucky. Cannot rule out some frost patches for the deeper valleys Friday or Saturday night, but will continue to leave mention out of the grids and monitor its threat with subsequent forecasts. Made mainly terrain based adjustments to the CR init starting point T grids each night through the period. Also, fine tuned the highest PoP pattern from 00z Friday through 00z Saturday to better time the actual fropa.
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&& .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) ISSUED AT 120 AM EDT WED OCT 19 2016 VFR conditions are expected through the TAF period. We have however seen some mid level clouds at around 5 to 6 KFT streaming across portions of the region. Therefore kept SCT to BKN deck at most sites through the night and into the day today. The only site that may see better coverage of clouds is SYM, as they remain closer to the boundary. Also introduced VCSH toward dawn for SYM, as some showers moving out of Ohio are possible based on consensus of the short term models. Winds have subsided and will remain light through the period. && .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.