Area Forecast Discussion
Issued by NWS Jackson, KY

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735 FXUS63 KJKL 261217 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 817 AM EDT Sun Mar 26 2017 .UPDATE... Issued at 816 AM EDT SUN MAR 26 2017 The area of showers is moving northeast slightly faster than was forecast, and adjustments have been made. However, there are no significant forecast changes. && .SHORT TERM...(Today through Monday) Issued at 439 AM EDT SUN MAR 26 2017 A weakening stacked low pressure system is centered in the vicinity of Quincy, IL and Burlington, IA early this morning. The mid/upper level portion of the system has a trough axis extending southeast to the Gulf of Mexico. As the trough moves northeast, it is interacting with a moist flow of air off the Gulf, resulting in a large area of showers. The leading edge of showers is over the southwest part of the JKL forecast area early this morning, heading east northeast. The area of showers will make its way across the rest of the forecast area this morning, and the back edge will exit into WV around mid day. There is no change in surface air mass taking place with this round of precip. However, there are colder temperatures aloft behind the leading band of precip. This has resulted in scattered showers and a few thunderstorms during the night over western KY and West TN. As the regime shifts eastward today, forecast soundings show instability developing to support showers and thunderstorms here. Uncertainty exists in the extent of coverage. While everyone should see rain out of the leading band of precip coming through early, that may not be the case in the afternoon. Whatever showers/storms do occur will be on the decline and moving out to the northeast with the upper level system tonight. Another surface low pressure system and an associated wave aloft will move northeast toward the Ohio valley on Monday. This will bring with it another increase in showers and thunderstorms, aided by diurnal destabilization. The peak in activity will likely come on Monday evening, beyond the short term period. .LONG TERM...(Monday night through Saturday) Issued at 439 AM EDT SUN MAR 26 2017 One of a string of upper Level waves that is moving into the Four Corners region this morning based on the 00Z 500mb analysis will bring a decent shot of showers and thunderstorms for the beginning of the period Monday night. This wave will induce a surface low across the Central Plains by tonight and eject into the Ohio Valley Monday night. Models seem to be handling this well and feel more confident in this versus much of the rest of the long term portion of the forecast. Tuesday the system will continue to progress east and trim POPs through the day from west to east. Models are in decent agreement with the drying period from Tuesday night into Wednesday night. While there is some amplitude differences with the upper level ridge and height rises think there is enough to keep the region dry. This also coincides with the NAEFS relative min in PWATs. Beyond this models become quite convoluted and begin to diverge in their respective solutions. The 00Z GFS wants to bring a more positively to neutral tilted closed low east out of the Plains by Thursday night and the 00Z ECMWF bring a more neutrally to slightly negatively tilted trough with more of a northern stream influence by the same time frame. This seems to be a phasing issue and these two solutions will have implications on the surface features as well. There also remains a reasonable amount of spread in the GFS ensemble mean in regards to the upper level feature and spread in the individual members with regards to low placement hints previous statement. Even given some uncertainty the fact that both solutions would bring a decent shot of showers and perhaps some thunderstorms went with likely POPs from west to east from Late Thursday into Friday evening. The blend wanted to go CAT POPs but felt like uncertainty would be too much for that bullish of POPs. This system pegged to move into the Mid Atlantic and therefore a period of drying will resume Saturday. Overall the period will be met with well above to above average temperatures. && .AVIATION...(For the 12Z TAFS through 12Z Monday morning) ISSUED AT 816 AM EDT SUN MAR 26 2017 Showers were occurring over all but the southwest part of the area at the start of the period. The continuous rain will move northeast out of the JKL forecast area by about mid day. However, there will still be at least scattered showers in the area through the afternoon, and possibly some thunderstorms. Conditions were mostly VFR this morning. This will remain the case, but sub-VFR conditions may affect some locations, especially where heavier showers or storms occur. The showers and thunderstorms will diminish tonight. Winds will pick up from the south to southwest during the day, with gusts around 20 kt. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HAL SHORT TERM...HAL LONG TERM...DJ AVIATION...HAL is the U.S. government's official web portal to all federal, state and local government web resources and services.