Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 181845 AAC AFDJKL AREA FORECAST DISCUSSION...UPDATED National Weather Service Jackson KY 145 PM EST Sun Feb 18 2018 .UPDATE...
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Issued at 112 PM EST SUN FEB 18 2018 Hourly grids have been freshened up based on recent observations. This led to no substantial changes at this time. UPDATE Issued at 1125 AM EST SUN FEB 18 2018 Surface and upper level high pressure will remain in control of the weather today. A few fair weather cumulus will be present through early to mid afternoon until the low levels dry out further, with high clouds increasing late ahead of a warm front. A window of clearing and light winds should support decoupling of eastern valley locations and development of a nocturnal inversion. A moderate ridge/valley split in low temperatures late this evening should occur with min T near midnight for eastern valley locations. Although COOP MOS lows are probably a bit too low, min T should easily fall below blended guidance for tonight. It also appears that showers should generally hold off until the 4Z to 6Z period for the southwest part of the area and then spread northeast as a warm front approaches. Adjustments to pops for timing trends have been made accordingly. UPDATE Issued at 626 AM EST SUN FEB 18 2018 The forecast is looking good so far this morning. The latest obs were ingested into the hourly grids to establish new trends. No update is planned at this time.
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&& .SHORT TERM...(Today through Monday) Issued at 303 AM EST SUN FEB 18 2018 A ridge of high pressure will keep the weather across eastern Kentucky dry today. Winds should be generally light and variable with partly cloud skies on tap as well. The weather will become wet again tonight, as an area of low pressure moving northward through the Great Plains, drags a warm front across the Tennessee and Ohio Valley regions. The rain should begin around 0Z tonight and will likely be coming to an end by late Monday afternoon. Rainfall amounts should be light, so no flooding issues are anticipated from this rainfall. Temperatures are going to be well above normal in the short term, as strong southerly flow along the west edge of a strong area of high pressure sets up across the region. Highs are expected to be in the mid to upper 50s today, and in the lower 70s for Monday. Tonights lows will only fall into the mid to upper 40s for most locations. .LONG TERM...(Monday night through Saturday) Issued at 415 AM EST SUN FEB 18 2018 Similar to last night, the models are in pretty good agreement with the overall longwave pattern aloft through the extended as they all depict persistent and strong ridging through the southeast and troughing to the west. This sets up a near continuous deep layer flow of warm and moist air from the southwest direction - off the western Gulf - up through the Ohio Valley. The ridge expands enough into the southern Appalachians early in the long term to likely protect eastern Kentucky from any impulses sliding by well to the north. This does change on Wednesday, though, as the ridge retreats to the southeast in all models with energy packets rolling east northeast along the Ohio River. Clusters of energy will continue to use this route into the upcoming weekend with Kentucky under the gun for the effects of mid level waves strafing by the state from Wednesday on through Saturday. More dissension is introduced into the models by the weekend as the trough to the west comes east quicker and flatter in the GFS than the ECMWF. However, for Kentucky there will be little distinction in the pattern with southwest flow holding pat. Given the overall model agreement will favor a blended solution for the grids after accounting for local effects - favoring the ECMWF for differences late. Sensible weather will feature anomalous warmth through Wednesday with the precip chances to the northwest during the bulk of this time. Strong southwest flow will support unseasonable - record setting (possibly for the entire month) - temperatures for the area Tuesday and Wednesday. The sfc high pressure to the east responsible for the summer-like temperatures will shift further east on Wednesday allowing a cold front to move into the area and stall out. In addition to a threat of periods of excessive rainfall from this lingering boundary sfc based instability should be enough for some thunder chances Wednesday into Wednesday night. Surges of moisture will then seep northeast along the front from Thursday through Saturday with more showers expected - though indications are that the heavier rains will more likely concentrate in locations closer to the Ohio River and just to the north as the southeast high helps to shield eastern Kentucky from the direct storm track for much of the time. We will need to watch this situation, though, as plenty of moisture will fall and should it be further south than anticipated flooding concerns will be renewed and extended through the upcoming weekend. Again made some significant adjustments to temperatures at night for expected ridge to valleys splits Monday and Tuesday nights along with Friday night. Did also tweak the PoPs through the period to better match the 00z ECMWF surges late in the period. && .AVIATION...
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(For the 18Z TAFS through 18Z Monday afternoon) ISSUED AT 125 PM EST SUN FEB 18 2018 VFR conditions will prevail across the region through 5Z as high pressure departs to the east. A warm front will approach the area this evening and move north of the area during the last 6 hours of the period. High clouds will increase during the first 6 to 9 hours of the period with mid and low level moisture increasing from around 3Z. Clouds will move into the area or develop at those levels shortly thereafter with ceilings decreasing to MVFR in the southwest near KSME around 6Z. This will gradually spread north and east with at least 3 to 5 hours of MVFR CIGS and VIS anticipated in rain showers at all locations through 12Z. Ceilings should increase back to VFR from the south and southeast as the warm front lifts north of the area during the last 6 hours of the period. Winds should be generally 10kt or less through the period, with higher sustained speeds and gusts above 2500 feet near the VA border.
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&& .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...AR LONG TERM...GREIF AVIATION...JP is the U.S. government's official web portal to all federal, state and local government web resources and services.