Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 180823 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 423 AM EDT Wed Apr 18 2018 .SHORT TERM...
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(Today through Thursday) Issued at 423 AM EDT WED APR 18 2018 A warm front will continue lifting through the Tennessee Valley and into eastern Kentucky this morning as a surface low moves out of the central Plains into Missouri. Developing cloud cover across central into eastern Kentucky has mainly remained in the mid levels, around the 5-7k foot level, as subsidence has held strong by way of weak ridging. Easterly surface winds ahead of the warm front have helped to maintain local downslope flow, thus negating precipitation chances this morning. Clearing skies this morning will gradually give way to increasing clouds downstream of an upper low approaching Lake Michigan this afternoon. Increasing southwest flow on the southern flank of a 1003 mb surface low will promote a quick warmup with temperatures climbing into the low-mid 70s this afternoon. The pressure gradient will further increase later this afternoon into this evening as the surface low tracks along the Ohio River. Additionally, 30-40 knots of wind will reside beneath a lingering subsidence inversion, adding to the likelihood of gusty winds through peak heating/mixing this afternoon and early evening. Have once again hoisted a Lake Wind Advisory for Lake Cumberland, Laurel River Lake, and Cave Run Lake as sustained winds will approach or at times exceed 20 mph with gusts nearing 35 mph at times later this afternoon into early tonight. Rain chances will increase this evening along/ahead of the approaching cold front. Shallow saturation, through about 8k feet off the surface, will help to keep rainfall amounts mainly below 1/10 of an inch as forcing aloft weakens with time as it phases with an upper low across the St. Lawrence Valley. Could potentially see a few snowflakes in the higher terrain near the Virginia border tonight, but the combination of forcing/moisture currently looks to lose definition by the time temperatures would become cool enough. A raw Thursday will be on tap as surface ridging builds into the Midwest and promotes a cold air advection regime. Upslope flow will keep low stratus in place for a good portion of the day, contributing to temperatures likely only warming to near 50 degrees. .LONG TERM...(Thursday night through Tuesday) Issued at 325 AM EDT WED APR 18 2018 The models are in fairly good agreement aloft through the long term portion of the forecast. They all depict the departure of the latest large upper low off to the northeast on Friday allowing heights to rebound over Kentucky. Omega block style ridging then works east from the Plains basically dampening out as it moves into the state through the weekend as the next upper low takes a more southern route through the Southern Plains. This latter feature is fastest to come east in the GFS with the ECMWF lagging and a notch stronger. The Canadian seems to support the ECMWF`s solution better at this time step into Sunday morning. This low then fades out as it slowly works east into the Tennessee Valley and Deep South to start the next work week. Meanwhile the northern stream will become more active as a strengthening trough moves into the Upper Midwest and Great Lakes region leaving eastern Kentucky in an area of weak mid level flow, almost col-like. Given the model similarities will favor a general blend solution with little in the way of adjustments or nudges toward any of the operational models. Sensible weather will feature cool high pressure slowly crossing the region to end this work week and continue into the weekend. From this a frosty night can be expected Thursday night into Friday morning. The high will moderate in time with the main aspect being to hold pcpn at bay for a fairly long stretch of time - definitely a break from the pattern of the past several months. We will need to watch the efforts of a southern low trying to work east and pick up some more Gulf moisture - but at this point it seems that this system will hold off through the weekend and potentially into the next week - though the GFS does bring in some rain by Monday morning with the ECMWF showing less conviction with its wetting of eastern Kentucky for Monday into Tuesday. Made mainly terrain based adjustments to the lows most nights next week depending on the sfc advection pattern. Did also beef up the PoPs in the far southeast through the start of next week in line with the midpoint of the ECMWF and GFS solutions.
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&& .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) ISSUED AT 200 AM EDT WED APR 18 2018 A warm front continues to lift north toward the eastern Kentucky airspace, but clouds have so far been mainly confined to at or above FL045. Additionally, ceilings have yet to develop as high pressure has so far produced enough subsidence to negate these, but will continue to keep an eye on this potential through the night. Other concern for tonight and early Wednesday morning will be low level wind shear, particularly at SME/LOZ. Have left this mention out for now as 30 knots of wind within the lowest 2000 feet off the deck will advect north early this morning, as surface winds quickly veer southwesterly and increase to 10-15 knots. There may be a narrow window between about 11-14Z where this threat will be maximized, but current indications point to this being a minimal threat. Southwest winds will continue to increase and gust through the latter morning and afternoon, with speeds approaching 15-20 knots with gusts of up to 25-30 knots. A strong low pressure system moving between CVG and CMH this evening will keep winds elevated and gusty as they veer more west to just northwesterly tonight. This system will usher in a cold front, bringing the chance for some rain this evening into tonight, complete with likely MVFR ceilings in its wake into Thursday morning. && .JKL WATCHES/WARNINGS/ADVISORIES...
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Lake Wind Advisory from noon today to 2 AM EDT Thursday for KYZ051-052-060-079-080-083>085-106.
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&& $$ SHORT TERM...GUSEMAN LONG TERM...GREIF AVIATION...GUSEMAN

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