Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 300309 AFDJKL Area Forecast Discussion National Weather Service Jackson KY 1109 PM EDT FRI JUL 29 2016 .UPDATE... Issued at 1109 PM EDT FRI JUL 29 2016 The update mainly blends obs into the overnight forecast grids. With just spotty showers heading in from the west, the POP has been placed at 20% overnight. Short range models would also suggest spotty coverage. UPDATE Issued at 859 PM EDT FRI JUL 29 2016 Precip has mostly died out in the JKL forecast area, but persists upstream in central KY and southern OH. It should be on an overall decline this evening, but short range models still generate spotty precip overnight. Will continue with low pops already in the forecast. && .SHORT TERM...(This evening through Saturday night) Issued at 336 PM EDT FRI JUL 29 2016 The models are in good agreement with cyclonic flow aloft and continuing to suppress the upper level ridging to the south. This will interact with the nearby boundary to bring chances of storms through the short term period. This afternoon WSR-88D showing showers and thunderstorms are moving east mostly across areas along and south of the Mountain Parkway. Some of these storms will bring locally heavy rain and gusty winds. These storms are expected to spread east into the early evening hours. HRRR has a decent handle on the main area of precip across the southern half of the CWA. Therefore blended pops in that direction given the reasonable timing. It does look like much of the convection will be diurnally driven, but given the pattern keep isolated pops through the night. Another issue that remains in question tonight will be fog and how much we see. Right now will go with at least patchy fog in the valleys but cloud cover could help mitigate some locales. Then another stormy day on tap for Saturday, as higher PWATS remain in place and quasi stationary boundary remains near. Right now once again going scattered coverage in the afternoon hours. Not really favoring any certain model at this point and went toward a blend approach at this point given the scattered coverage. Once again expecting more in the way of diurnally driven activity and therefore lessen the coverage once again on Saturday evening. Temperatures through the short term period will run near normal. .LONG TERM...(Sunday through Friday) Issued at 435 PM EDT FRI JUL 29 2016 The models are in fairly good agreement aloft through the extended portion of the forecast. They all depict a retreat of the Great Lakes trough through the start of next week while strong mid level ridging reloads over the southern plains and east through the Deep South/Tennessee Valley. As this happens, though, plenty of energy will drift through the Ohio Valley from Sunday through Monday before higher heights shunt it all off to the northeast, temporarily. After this, the ridge does retreat to the southwest a tad and subsequently allow for more ridge riding energy packets to potentially target eastern Kentucky from Wednesday through Friday, most clearly evident in the latest ECMWF. Given the general agreement, a model blend looks to be a reasonable place to start for gridded forecast purposes. Sensible weather will feature rounds of mainly diurnally enhanced showers and thunderstorms through Monday. Heat will gradually rebuild through the area for the start of the week with some 90 degree readings anticipated for the latter part of the forecast. However, the worst of this round of heat will likely be tempered by scattered convection from Wednesday to Friday. It looks like the lowest PoPs will be from Monday night through Wednesday morning as the core of the ridge is closest to our area and SFC high pressure builds in briefly from the northeast. For the CR initialization: made some minor changes to MinT and hourly T each night with some terrain differences anticipated due to radiational cooling in the valleys. Did make some mainly diurnal adjustments to PoPs through the forecast period, as well. The rest came in real good. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) ISSUED AT 859 PM EDT FRI JUL 29 2016 Convective precip affected most of the area during the afternoon or early evening. This has left cooled air at the surface and high RH at the start of the night. Precip has mostly died out, but persisted over central KY and southern OH. The main concerns will be the extent of fog development tonight...and whether the area of precip to the west and north will make it here. Think that there will be an overall decline in precip as we head through the night, and confidence in anything happening at a particular TAF site is too low to warrant inclusion of precip tonight. The stage is set for fog development, but the extent of cloud cover will modulate the fog. Will call for conditions to fall to at least IFR at all TAF sites. However, timing and just how low the visibility goes is still somewhat uncertain. Fog and low clouds will dissipate on Saturday morning. A general repeat of the convection cycle is expected during the day, with heating causing showers and thunderstorms to percolate, mainly during the afternoon and early evening. With uncertainty in timing and location, the best that can be done at this point is too use VCTS in TAFs. && .JKL Watches/Warnings/Advisories... None. && $$ UPDATE...HAL SHORT TERM...DJ LONG TERM...GREIF AVIATION...HAL

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