Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 291502 AAA AFDJKL AREA FORECAST DISCUSSION...UPDATED National Weather Service Jackson KY 1102 AM EDT Mon May 29 2017 .UPDATE...
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Issued at 1102 AM EDT MON MAY 29 2017 Thicker cloud cover is hanging on a bit longer than expected. As such, have freshened up the sky cover over the next few hours, as well as tempered the diurnal rise a bit more through early this afternoon. Some weaker echoes are noted on radar west of I-75, but this is mainly in the mid-levels and doubt any of this is reaching the ground. Will keep things dry today as the weakening cold front pulls away to our southeast. Forecast highs of around 80 degrees still look on target. UPDATE Issued at 804 AM EDT MON MAY 29 2017 Hourly grids were updated based on recent observations. This led to no substantial changes at this time. Low clouds linger across parts of the area, but with daytime heating these should slowly mix out.
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&& .SHORT TERM...(Today through Tuesday) Issued at 420 AM EDT MON MAY 29 2017 The period begins with a closed low over the Northern Great Lakes and Ontario with an associated trough south into the MS Valley region. Upper level ridges were in place across the Western Conus and Gulf of Mexico and Caribbean. At the surface, low pressure was over Ontario with an occluded front to a triple point low over the eastern Great Lakes with a cold front trailing south and then southwest into the OH Valley to the Southern Plains. A secondary front extended from the low into the WI and then west across parts of the MO Valley. Today and tonight, the first cold front will depart into VA and TN early and begin to stall south of the area with high pressure nosing northeast into the region from the Southern Plains. Mid level heights should rise some and then remain steady this afternoon capping off any cu development. Mid level clouds should depart early with areas of stratocu or stratus mixing into rather shallow cu through the morning and into the afternoon. There should be a period with mostly clear skies from near sunset into very early on Tuesday morning and this may allow for a small ridge/valley temperature split to develop with a nocturnal inversion setting up in the valleys. The secondary cold front should increase late with an associated increase in low and mid level clouds. Highs today should be near to slightly above normal for the end of May with lows tonight near to slightly above normals as well. On Tuesday, the secondary cold front will cross the region with limited moisture. Moisture should be a bit more substantial across the southern and southeastern counties closer to the stalled frontal zone and somewhat higher dewpoints. The bulk of the model guidance suggests isolated to scattered coverage of showers and perhaps a few thunderstorms near the VA border. The past two NAM runs appear overdone with moisture and instability and thus coverage of convection and were weighted very little for this forecast. GFS forecast soundings across the north indicate less instability and perhaps a bit of capping so thus thunder chances were confined to one to two counties nearer to the VA and TN border where CAPE could reach near 500 J/kg and LI on the order of -2C. With more cloud cover, highs on Tuesday should be slightly lower as compared to today. .LONG TERM...(Tuesday night through Sunday) Issued at 345 AM EDT MON MAY 29 2017 A weak cold front will slip south across the area late Tuesday night and Wednesday. Forcing with the front will be quite weak, but instability may build south of the front on Wednesday and spark a few showers and thunderstorms, especially across the southern half of our forecast area. Looking at 00z model forecast soundings, there would be some potential for a few strong or damaging wind gusts as we have modest speed shear from the surface to 500mb. We also have a pocket of mid level dry air that may aid in the potential for some downburst winds. The best threat for the stronger storms would be in southeast Kentucky at this time. Front will push south Wednesday evening, with showers and storms exiting south. As high pressure builds south across the region, this will provide dry weather Wednesday night through Thursday night. As the high shifts east Friday, moisture will start to stream back to the north from the Gulf region. A mid level trough will push north and could spark some showers and storms during the day Friday. In the wake of this system, looks like plenty of moisture will reside over the region through the weekend. It looks like a zone of active convection will develop and align east to west again through the weekend. PW values will climb back to around 1.50 to 1.60 inches over the weekend. With the mean steering flow aligned with the east to west front to our north, we could be looking at more potential for flash flooding. Models are in good enough agreement to at least mention the potential in the HWO. Looks like front will finally push south Monday night, ending the threat of heavy rain. With the active weather over the weekend, will maintain the likely rain chances from Saturday through Sunday. Taking a very early look at severe potential, it appears shear will be too weak to support much of a severe risk. Thus, this time around, we could be more focused on hydro concerns. && .AVIATION...(For the 12Z TAFS through 12Z Tuesday morning) ISSUED AT 750 AM EDT MON MAY 29 2017 Some stratocu or stratus lingers across much of the area with a mix of MVFR and IFR occurring. The IFR was more prevalent across the north. This should lift into MVFR during the first 2 to 3 hours of the period with MVFR improving to VFR areawide by 15Z to 16Z. VFR should then prevail through the end of the period with a weak ridge of high pressure dominating. Winds should generally remain at 10KT or less through the period. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEOGERIAN SHORT TERM...JP LONG TERM...KAS AVIATION...JP is the U.S. government's official web portal to all federal, state and local government web resources and services.