Area Forecast Discussion
Issued by NWS Jackson, KY

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229 FXUS63 KJKL 271902 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 302 PM EDT Mon May 27 2024 .KEY MESSAGES... - There will still be a chance for thunderstorms today until a cold front has completed it track across eastern Kentucky by late this afternoon. - Following today, generally cooler and less humid weather will be in place over the next several days. Warmer and somewhat more humid weather is then forecast to make a comeback for the upcoming weekend along with our next area-wide chance of showers and thunderstorms. && .UPDATE... Issued at 1256 PM EDT MON MAY 27 2024 Temps are looking on track. Made some additional minor adjustments to afternoon PoPs (lower) based on trends in the CAMs. No other adjustments other than to freshen up the zone wording to remove morning references. UPDATE Issued at 1108 AM EDT MON MAY 27 2024 Updated the forecast package this morning to reduce PoPs and to bring grids in line with hourly observations. Rain has moved out of the area this morning. However, the surface cold front is only just getting into our forecast area. It will not pass through to our east until late today. The boundary itself is hard to distinguish other than a slight wind shift. The drier, cooler air will not be noticeable across the area until tonight, once the H850 trough has managed to pass through the region sometime during the evening. Mesoanalysis shows a pool of slightly more moist and unstable air just ahead of the surface boundary. MLCAPEs ahead of the front will climb to between 750-1000 J/kg and there is still some marginal effective shear in place at around 30kts. So a few showers and thunderstorms will still be possible until the front has passed to our east. Therefore allowed for a slight increase in PoPs across mainly our southeastern zones for this afternoon with stronger diurnal heating. This would seem to be supported by the hrrr which continues to show a threat of isolated to widely scattered activity across the area over the next few hours. Zones and grids have been updated and issued. Will update the zones to freshen up wording by early afternoon. UPDATE Issued at 746 AM EDT MON MAY 27 2024 No major changes to the forecast for the morning update. Nudged PoPs down a bit based on latest radar trends. In addition, high- res guidance suggests less shower/storm coverage along the cold front until we see a bit of heating later this morning. Therefore, have shifted coverage of precipitation further east where the frontal position coincides with solar heating and modest destabilization. && .SHORT TERM...(Today through Tuesday) Issued at 440 AM EDT MON MAY 27 2024 08Z sfc analysis shows low pressure moving through the Ohio Valley with a cold front draped northwest of the area. A squall line of strong to severe thunderstorms - along with embedded potential brief tornadoes - has now exited the area well ahead of the front. Lighter showers and a few embedded thunderstorms follow the main thunderstorm line but will rain itself out over the next couple of hours. This will mean little threat of flooding now so the Flood Watch was also cancelled. Mostly cloudy skies with patchy fog and generally south to southwest winds of 10 mph or so. Temperatures and dewpoints are fairly uniform across the area post storm - generally in the low to mid 60s. The models, and their individual ensemble suites, are in good agreement aloft through the short term portion of the forecast. They all depict general troughiness through the Ohio Valley that will be reinforced by a couple of shortwaves moving though the region. The first of these clears out this afternoon but another swings by to the north tonight. The small model spread supports using the NBM as the starting point for the short term grids along with the incorporation of the CAMs` details for PoPs and timing mainly just through this afternoon. Sensible weather features drying conditions as the bulk of the rains, along with any fog and low stratus, clears out shortly after sunrise. The front settling through the area then brings a renewed chance for showers and storms moving northwest to southeast through eastern Kentucky into this afternoon. Drier weather follows tonight, though the valley fog will likely be more prevalent along with a small ridge to valley temperature split. Still some clouds around on Tuesday - mainly for the northeast but a pleasant day overall with only the barest chance for a stray shower - probably staying to the northeast of the area. The main adjustments to the NBM starting point consisted of adjusting the NBM PoPs to include CAMs details for the shower and thunder chances through this afternoon. The temperatures from the NBM were adjusted tonight to include more terrain details on account of a decent bout of radiational cooling expected. .LONG TERM...(Tuesday night through Sunday) Issued at 350 AM EDT MON MAY 27 2024 The models, and their ensemble suites, are in decent agreement aloft through Thursday before they start to separate into the weekend. They all depict upper level longwave troughing dominating the eastern CONUS through most of the work week before ridging spreads in with a return to troughing late. Multiple shortwave troughs will rotate through the initial larger trough during this time. A lead shortwave dives into the area and passes through on Wednesday. This is followed by a secondary one moving by the area further east - quicker in the ECMWF suite than the GFS and also favoring the northeast compared to the lagging GFS. This will be the biggest difference among the models through the period but they do get back in line later Friday. By Friday, ridging will move back over the area with significant height rises. However, this does not last long as another trough starts to impinge the Ohio Valley from the Southern Plains on Saturday - potentially rolling into eastern Kentucky on Sunday - again quickest from the ECMWF suite. Though it was evident, the model spread was not sufficiently large to deviate too far from the blended multi- model solution of the NBM. Sensible weather will feature a cool down, and less humidity, through the middle part of the week along with some shower and thunderstorm chances Wednesday afternoon. High pressure then brings drying and more sunshine to close out the week and start the weekend, though the next system returns shower and storm chances to the area later Saturday into Sunday. The main adjustments to the forecast was to fine tune the overnight temps and lows for terrain distinctions Wednesday night through Saturday morning. && .AVIATION...
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(For the 18Z TAFS through 18Z Tuesday afternoon) ISSUED AT 302 PM EDT MON MAY 27 2024 Expecting predominant VFR conditions through the period with CIGS right around 030 AGL. Consequently, there will be an occasional drop into high end MVFR conditions at TAF sites during the first few hours of the forecast. Sustained winds will be out of the west at 10-15 kts with occasional gusts to around 20 kts through the first 4-6 hours of the period and should slacken with sunset, becoming light from the west-southwest. The more sheltered valley locations will become variable. Winds will increase again for Tuesday afternoon, out of the west-northwest. Drier air filtering into the area through the overnight will tend to keep fog/mist at a minimum.
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&& .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...RAY SHORT TERM...GREIF LONG TERM...GREIF AVIATION...RAY