Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 211937 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 337 PM EDT Wed Jun 21 2017 .UPDATE... Issued at 207 PM EDT WED JUN 21 2017 The forecast remains on track. Once again, just freshened up the hourly temperatures and dew points through the rest of the afternoon. Updates have been sent. UPDATE Issued at 1132 AM EDT WED JUN 21 2017 Mainly just freshened up the hourly temperatures and dew points through this afternoon. Forecast highs mainly in the mid 80s, with a few upper 80s, look on target. Updates have been sent. UPDATE Issued at 805 AM EDT WED JUN 21 2017 Hourly grids were freshened up based on recent observations and trends. This led to no substantial changes at this time. && .SHORT TERM...
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(Today through Thursday) Issued at 425 AM EDT WED JUN 21 2017 Early this morning, surface high pressure was located over the Appalachians. Thicker cirrus is streaming from West Tn east northeast to the KY/VA border region into the Central Appalachians. The region is in a seasonably moist airmass between weak cold front or outflow boundary north of the Ohio River and nearly stationary boundary from east TX east northeast to the Delmarva which is the leading edge of the much deeper tropical moisture to the south. This moisture is being transported into the Gulf states around Tropical Storm Cindy. Aloft, an upper level trough extended south from Ontario and Quebec and Ontario into the Great Lakes and parts of the OH Valley with a ridge centered southwest of Bermuda and another ridge centered over the Desert Southwest. In between was weakness with the center of Tropical Storm Cindy over the Gulf of Mexico. Observations indicate generally less in the way of valley fog compared to recent mornings. Through this morning, a general decrease in the thickness of the cirrus is expected for most locations through some debris mid and high clouds could affect northern portions of the area. The axis of the trough to the north and northeast of the area will shift to the north and east today with an increase in mid level heights. Some diurnally driven cu may form but should be rather shallow or capped by some subsidence. Temperatures should moderate further from readings over the past couple of days with surface and upper level high pressure dominating. Highs should average above normal, generally in the mid 80s with a few upper 80s across the area with slightly warmer readings in the north with a bit less in the way of clouds. Through today and into tonight, the center of tropical storm Cindy should continue moving across the northern Gulf of Mexico and associated upper low should move toward the upper TX coast with the southwest US ridge and ridge near Bermuda remaining in generally the same location and strength. Disturbances will pass by to the north in rather quick westerly flow. East KY will dominated by surface and upper level ridge through the night, but moisture will begin to increase especially in the southwest. PW will also begin to increase today and especially tonight form values currently near 1 inch to an inch to an inch and a third by sunset. The more dramatic increase will occur tonight and into Thursday with values reaching in excess of 1.5 inches toward sunrise on Thursday. As the center of Cindy moves into the upper TX coast or western LA as well as an upper low moisture will continue increasing form the southwest with some isentropic lift across the area. PW should climb above 1.5 inches in the far north and east by the end of the period with PW nearing or exceeding 2 inches in the far southwest at that time. A shortwave should also approach in the westerlies at the time. This and some solar insolation will lead to increasing chances for showers and a few thunderstorms through the day though the west moisture and lift will be in the southwest where chances and qpf are expected to be the greatest through 0Z Friday. However, the heaviest rainfall should off until the long term period. .LONG TERM...(Friday through Wednesday) Issued at 337 PM EDT WED JUN 21 2017 The extended forecast begins on Friday with the subtropical ridge still in place over the southeastern CONUS bringing tropical moisture northward into Kentucky as the remnants of Tropical System Cindy moves into the Mid MS Valley and then east into the TN Valley. The latest run has brought the heaviest rainfall a bit further north than the previous run into Kentucky. Thus will keep QPF amounts from the super blend with a blend of the WPC amounts. Consistency in the model runs continue to keep the heaviest rainfall in the area Friday night with PWAT values well above 2 inches. So will continue to mention heavy rainfall Friday night in the HWO with the more moderate rain beginning on Friday. In addition to the heavy rainfall with the abundant moisture and increased shear, a few strong storms can`t be ruled out for Friday with some gusty winds being the main threat in addition to flooding. This element is complicated based upon the amount of forcing imposed by the cold front dropping south Friday as well. The onset of some instability to the situation could set the stage for a few severe storms as well. After this the heaviest rainfall arrives Friday night with models coming into agreement that the system will exit by Saturday evening. After the amalgamation of the front and remnants of Cindy pass through during the day on Saturday, brief ridging passes by for Saturday night and into Sunday morning with the next wave pushing into the area by Sunday afternoon. The pattern indicates a continued strong southerly surge of Gulf moisture into the area. Thankfully the upper level pattern continues to hint at a zonal and progressive flow as the shortwave pushing through will quickly exit by Monday afternoon. In addition, current model profiles indicate little instability and will seem to lack the deep convection for heavy rainfall keeping a more steady rainfall for Sunday afternoon through Monday morning. This will be a welcomed pattern as the rainfall over the first half of the weekend from Cindy will likely leave many locations flooded or at least creeks and streams running high. The extended forecast period will come to an end By Tuesday night with ridging settling in once again across Kentucky for Monday night through Tuesday night.
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&& .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) ISSUED AT 207 PM EDT WED JUN 21 2017 High pressure will maintain control through late this evening, with afternoon cumulus dissipating by dusk. A low level jet will then increase from the south and southwest towards dawn Thursday, bringing lowering ceilings and eventually showers and a few thunderstorms to the area during the day on Thursday. West southwest winds at 5 to 10 kts, will gradually back to the south southwest later in the period. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEOGERIAN SHORT TERM...JP LONG TERM...SHALLENBERGER AVIATION...GEOGERIAN

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