Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 151925 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 325 PM EDT Thu Mar 15 2018 .SHORT TERM...
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(This evening through Friday night) Issued at 325 PM EDT THU MAR 15 2018 A cold front over the northern part of the forecast area will work its way south across the forecast area tonight. The front will stall over TN on Friday. The front will then serve as a focus for precipitation as it gradually lifts north Friday night in response to low pressure moving east from the plains into the Mississippi Valley. The model trend has been for a slower onset of precipitation, and also warmer temperatures Friday night. At this time any freezing rain Friday night looks to occur north and northeast of the forecast area. Some mid level clouds, associated with a jet streak, have lingered across the center part of the forecast area through much of the day. These should gradually shift south overnight. Despite a gradual increase in clouds in the south and eventually the central part of the forecast area late tonight, there should still be enough radiational cooling in the valleys for at least a small ridge valley temperature difference to develop tonight. .LONG TERM...(Friday night through Wednesday) Issued at 505 AM EDT THU MAR 15 2018 The models remain in only fair agreement aloft through the long term portion of the forecast during this busy and progressive, transition season, pattern. Some agreement at the largest scale breaks down and become more disjointed at smaller scales through the forecast period. This results in lower confidence in any specific model solution and favors an ensemble and blended solution as a starting point. The models depict 3 separate and significant impulses to move through the region over the next week. The first of these comes out of the Central Plains as a closed low but dampens quickly as it slides east Friday night into Saturday. The GFS is quicker and weaker than the ECMWF and CMC with this feature. Fairly flat ridging follows for the area into Sunday with still plenty of energy packets moving through the swift mid level flow. For Monday, the next impulse will be inbound with the GFS again fastest, but with similar strength. The core of this dampening, but still distinct and healthy, wave rides over eastern Kentucky early Tuesday morning. The pattern then becomes more convoluted by mid week as more energy passes through the Midwest and into the Ohio Valley with heights falling and a full latitude trough taking shape over the region into Wednesday - quicker, further south, and not quite as strong in the GFS than the ECMWF - but similar enough to make for a clear trend toward continued active and changeable weather. Despite the larger than desired spread to the models it is clear that near normal to mild regional temperatures early on will turn colder toward the end of the period while damp conditions look to remain in place or worsen with time. Sensible weather will be quite active through the period with several sfc lows passing through the Ohio Valley from Friday night through Wednesday. The first of these will lift a warm front through eastern Kentucky Friday night into Saturday morning. The leading edge of this will push into cold and dry air in place over the northeast parts of the JKL CWA and the pcpn may catch up to this air to result in a brief period of mixed weather towards dawn, though the amount of warming aloft should mitigate this threat. In fact, the sfc low may also take advantage of its warm surge on Saturday to kick off a few thunderstorms, but model uncertainty precludes adding any TRW to the grids, at this time. Cooler and mainly dry weather follows into Sunday before the next warm front lifts into Kentucky early Monday with this later sfc low passing right through the state with showers and potential thunderstorms that afternoon followed by colder temperatures into Tuesday. Some snow may start to mix in later Tuesday and into Wednesday as the larger trough aloft takes shape and lowers sfc pressure throughout the region - though significant uncertainty remains at these later time steps. Made only minor adjustment to most of the temperature grids through the period, but did nudge them strongly toward the CONSRaw blend Friday night into Saturday (along with dewpoints). As for PoPs, again tried to limit them bulk of them to the sfc features - focused on each successive wave passage.
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&& .AVIATION...(For the 18Z TAFS through 18Z Friday afternoon) ISSUED AT 135 PM EDT THU MAR 15 2018 Mixing has allowed some stronger winds aloft to make their way down to the surface. As a result west winds will gust to between 20 and 30 knots this afternoon. The winds will diminish quickly this evening and become variable and light in most areas by Friday morning. VFR conditions will prevail through the TAF forecast period, with mid level clouds gradually increasing over southern and central parts of the forecast area tonight. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...SBH LONG TERM...GREIF AVIATION...SBH is the U.S. government's official web portal to all federal, state and local government web resources and services.