Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 191957 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 357 PM EDT Wed Oct 19 2016 .SHORT TERM...(This evening through Thursday night) Issued at 357 PM EDT WED OCT 19 2016 Surface map shows a stationary boundary just to our north along the Ohio River. High resolution models suggest this boundary will lift slightly northward tonight in response to a sfc wave of low pressure as it continues to develop over the Ozarks. This feature will move rapidly northeast overnight along the Ohio River Valley. This low should be between SDF and CVG by dawn Thursday and will pull a cold frontal boundary through our area as it continues to track up the Ohio Valley. The sfc front should be completely through our area by sometime Thursday evening. This system will bring our first opportunity for a substantial widespread rainfall in quite awhile. ATTM a blend of model and guidance QPF totals suggests between 0.75 and 1.25 inches of total rainfall will be possible with this storm system, some much needed rainfall should that come to fruition. Behind the front temperatures will take a slow but steady drive southward as much cooler air filters into the area late Thursday and Thursday night. Best chance of thunder will come during the day Thursday. SPC has our area in a Marginal Risk for severe weather. There is sufficient surface based instability and fairly strong 0-6 km shear, so can not rule out that possibility. However at this time forecast soundings suggest CAPEs will be relatively low. If soundings are correct, this will tend to counteract the potential for severe weather. And other sounding parameters are generally unimpressive. For now will keep current HWO wording suggesting only a few strong storms. .LONG TERM...(Friday through Wednesday) Issued at 357 PM EDT WED OCT 19 2016 There is good model agreement that at 12Z Friday the cold front will be well southeast of the area, with the axis of the mid level trough poised to move across the area during the day. Any lingering showers will be diminishing on Friday as the trough passes to our east. The standard model blend keeps a slight chance of showers in the far east into Friday evening, but after that there will be no mention of precipitation chances for the remainder of the forecast period. There is also good model agreement, including the GFS ensemble, that 850 mb temperatures will plunge to -1 to -2 C by 12z Saturday. At this time there is still some doubt about how much clearing will occur Friday night. Even with the sub freezing 850 mb temperatures Saturday morning clouds would keep temperatures warmer than might otherwise be expected. Will follow the standard blend and keep minimum temperatures around 40 degrees for most areas Saturday morning. While 850 mb temperatures will warm by 5 or more degrees by Sunday morning, it is likely that some valleys will have colder temperatures Sunday morning than Saturday morning, with generally clear skies expected by then and good radiational cooling conditions from Saturday night into Sunday morning. Will not mention frost at this time for Saturday or Sunday morning, but this possibility will need to be monitored for later forecasts. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) ISSUED AT 215 PM EDT WED OCT 19 2016 VFR conditions are expected through the forecast period. However, conditions will be deteriorating fairly rapidly just beyond the end of the forecast window. A low pressure system and its associated cold front will be moving through the region Thursday afternoon into Friday. This system will bring our first opportunity for a substantial widespread rainfall in quite awhile. Current CU field (bases 040 to 050) will expand for a couple more hours, then dissipate again as sunset approaches. Cloud cover will remain more substantial across our north closer to a stalled out surface boundary, affecting mainly SYM. Winds will be generally light around 5 kts or less, then increase again Thursday ahead of the approaching system, generally around 10 kts from the southwest. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...RAY LONG TERM...SBH AVIATION...RAY is the U.S. government's official web portal to all federal, state and local government web resources and services.