Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 170845 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 345 AM EST Tue Jan 17 2017 .SHORT TERM...
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(Today through Wednesday) Issued at 345 AM EST TUE JAN 17 2017 08z sfc analysis shows a well defined area of low pressure lifting northeast into the Great Lakes. This is dragging a cold front slowly east through the Mid Mississippi Valley and toward Kentucky. Additionally a northward moving warm front is currently lying across eastern Kentucky with a large area of convection rolling east along it. This cluster of showers, with a potential for embedded thunderstorms will continue to press deeper into eastern Kentucky from the west with a healthy dose of soaking rains expected for most places by dawn. The clouds and arriving showers, along with south stirring winds, have mostly mixed out the colder valleys, but there remain a few in the east that did manage to get into the upper 40s while most of the rest of the area reside in the mid to upper 50s with lower 60s found in several places south of Jackson. Dewpoints, meanwhile are running in the low to mid 50s most places. This is making for another quite mild mid January night - sitting at or near record max minimum temperatures - across the area. The models are in only fair agreement aloft through the short term as the southeast ridge holds fast no matter what troughs move by to the northwest. This will mean deep level southwest flow will continue supporting our current spate of mild and wet conditions through the near term. Specifically, an opening, southern stream, wave will shift off to the north of Kentucky today. This is followed by a fairly strong northern stream trough digging through the Ohio Valley tonight - only briefly dampening the heights over the region. The model spread is rather large for this feature particularly given that it is only 24 to 36 hours out. The ECMWF is a tad sharper and slower with this when compared to the GFS - but not as slow as the NAM. This wave will be driven in part by a 300 mb jet streak passing to our north with sustained upper level divergence over Kentucky today and tonight on its right entrance region. Ridging rapidly builds back over Kentucky later Wednesday in all models in the wake of the northern stream wave. Given the lowered confidence with that second wave tonight have favored a blended solution along with a lean toward the higher resolution HRRR for the near term. Sensible weather will feature a wet start to the day as a leading band of showers moves through eastern Kentucky followed by a brief lull around midday. By late afternoon another round of showers and potential thunderstorms will seep northeast into the area just ahead of a weakening cold front that pushes through during the first part of the night. Cooler and drier conditions follow into Wednesday morning, but readings will still be well above normal, as well as freezing, through the short term with a small rebound by the afternoon as high pressure quickly moves into the Ohio Valley. Started with the CONSShort and ShortBlend for most elements through the short term portion of the forecast - making only minor adjustments to temps and winds today. Also, adjusted PoPs more toward the HRRR in the near term. .LONG TERM...(Wednesday night through Monday) Issued at 305 AM EST TUE JAN 17 2017 Pretty good agreement between the model for the extended period. The general consensus is that a series of upper level southern stream weather systems will move across the Ohio and Tennessee valley regions. The first systems is forecast to move out of the souther Plains Wednesday night and Thursday. This system should bring rain to our area Thursday and Friday. The models agree that rain showers should being entering our area early Thursday morning. The rain will overspread the area from south to north through out the day on Thursday. The best chance for rain with this initial system should be from late Thursday afternoon through early Friday afternoon, as an area of low pressure by just to the north of the Ohio River and into the central Great Lakes region. After this first round of rain exits the area, we should experience a short break from precipitation, as a weak ridge of high pressure aloft sets up over the southeaster CONUS Friday night through early Saturday night. A second slightly strong area of low pressure is then expected to approach the area from the southern Plains Saturday night. This system may be slower moving than the first, so we could see a longer period of rain this weekend and into the beginning of next week. The first showers with this second system should move into eastern Kentucky late Saturday night. The rain will then gradually spread across the area on Saturday, with the entire area likely seeing accumulating rainfall by Saturday evening. The period from Saturday night into early Sunday morning looks to be quite wet, as the area of low pressure nearly stalls over top of us. This would allow the rain to linger across the area through Monday night. Temperatures through out the entire period will be well above normal for the time of year. Highs during the extended will vary from the 50s to the 60s each day, with nightly lows generally in the 40s. Some locations could fall into the mid to upper 30s Thursday morning. Some locations along and south of the Hal Rogers Parkway on Friday morning may only bottom out at or slightly above 50 degrees.
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&& .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) ISSUED AT 105 AM EST TUE JAN 17 2017 VFR conditions will start out the TAF cycle for most places, but as the cold front moves in from the west overnight widespread showers will press west to east into the forecast area. With this, ceilings and visibilities will gradually lower to MVFR, with some low level wind shear threatening in the east generally between 09 and 15z Tuesday. A few thunderstorms will also be possible across the entire area during this timeframe, with rain showers off and on through the rest of the day - Tuesday. South winds of 5 to 10 kts through dawn, will become southwest at 10 to 15 kts, with gusts of around 20 kts expected during the day Tuesday. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GREIF LONG TERM...AR AVIATION...GREIF is the U.S. government's official web portal to all federal, state and local government web resources and services.