Area Forecast Discussion
Issued by NWS Jackson, KY
Issued by NWS Jackson, KY
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429 FXUS63 KJKL 271908 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 308 PM EDT Thu Jun 27 2024 .KEY MESSAGES... - Hotter weather is expected to make a comeback on Friday and Saturday, and may now extend into Sunday, with afternoon highs around 90 or in the low 90s and heat index values peaking around or in excess of 100 degrees. - A cold front will likely bring additional rain to the area from late Saturday into Sunday. Any storms on Saturday afternoon and evening could produce strong wind gusts and heavy rain. - Another shorter-lived cooldown is anticipated for early next week followed by a mid week warm up. Heat indices may reach or exceed 100 degrees once again Wednesday of next week. && .SHORT TERM...(This evening through Friday night) Issued at 308 PM EDT THU JUN 27 2024 Differential heating boundary is slowly moving south toward the Tennessee and Virginia borders. However, this activity is tapping into some remaining weak instability and moisture, resulting in isolated showers. Cannot rule out an isolated thunderstorm or two south of the Hal Rogers Parkway/KY Highway 80 through this afternoon, but overall the trend through the rest of today will be for drying and clearing skies. Heading into tonight, a dry air mass settles over the area under surface high pressure, with some residual low-level moisture remaining along the Tennessee border area. This will support fog formation in the typically foggy sheltered river valley locations tonight into Friday morning, with lower confidence in fog formation elsewhere. Lows will generally be in the mid-60s, but a few 50s are possible in the cooler sheltered valleys. For Friday, east-west ridging across the Upper Tennessee Valley in the upper levels is expected. However, a weak mid-level low over the Deep South will weaken into an open trough and begin moving toward the area. This will allow for moisture to stream north across eastern Kentucky through the day. Sufficient moisture and instability will exist for isolated to widely scattered shower and thunderstorm activity in the afternoon, with continued low-end chances (20 to 30 PoPs) into the evening and overnight as a low- level jet develops and pushes additional moisture north into the area. This will make the low temperature forecast tricky for Friday night into early Saturday morning. However, with the warm advection and moisture transport into the area expect lows to remain elevated especially on the ridgetops and Bluegrass locations where lows may remain in the 70s, with some sheltered valley locations possibly falling to as low as the mid-60s, especially if there is sufficient clearing despite the increasing warm advection. .LONG TERM...(Saturday through Thursday) Issued at 217 PM EDT THU JUN 27 2024 The forecast period will begin with southerly flow ahead of an approaching shortwave. This upper-level feature is tracking through the Upper Great Lakes. A trough pivoting into the Upper Midwest into the Great Lakes will push a surface low through the region as well. Extending southwest from the low a cold front will extend from the Great Lakes toward the Commonwealth. Locally, surface high pressure will be in place and will advect warmer temperatures and Gulf moisture into the region. Highs for Saturday will be climbing into the upper-80s to low-90s with heat indices approaching the 100 degree mark. As the front approaches the region, increasing showers and thunderstorms are possible through the day Saturday. The SPC has placed the entire CWA under a Day 3 Marginal Risk for severe weather as forecast soundings ahead of the boundary show decent severe weather indices. Instability, steep lapse rates and high PWs are in place but the main ingredient lacking is sufficient shear to produce and maintain severe storms. Also, if there`s widespread cloud cover, instability value will remain meager and thunderstorms will become more limited. However, with PWs over 2.00", an efficient shower could put down some decent rainfall. Showers and storms continue into Saturday night through Sunday before the front passes mid- Sunday morning through Sunday afternoon. Height rises and surface high pressure will begin to nudge back into the region for Sunday night. A pretty decent temperature drop is expected for Monday as highs and dewpoints drop 10-15 degrees making it rather comfortable going into next week. However, this is short- lived as a forecast 594 dm dome of high pressure builds in overhead. This will allow for temperatures to climb back into the upper-80s to low-90s and a return of heat indices approaching 100 degrees. This pattern will remain in place through early Wednesday before another shortwave dives out of the Upper Midwest. The shortwave is forecast to track easterly with a cold front diving southeast into the Commonwealth and bring another round of showers and thunderstorms for the end of the forecast period. && .AVIATION...(For the 18Z TAFS through 18Z Friday afternoon) ISSUED AT 138 PM EDT THU JUN 27 2024 At TAF issuance, VFR conditions were occurring under clearing conditions from earlier cloud cover, with MVFR conditions and light rain over far southern parts of the forecast area south of KLOZ and KSME. High pressure continues to build over the area and is bringing drier conditions, resulting in cig bases rising to above 040. Winds are expected to be light and variable through the period. Valley fog with IFR or MVFR reductions is expected to develop between 04Z and ~12z, and this could lift into or affect a couple of the TAF sites, though confidence in this is low at this time. The latest statistical guidance is mixed on fog development tonight, but is most aggressive at KLOZ tonight. However, will pass on mentioning fog for late tonight with this TAF package pending newer (and hopefully more consistent) model guidance. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CMC LONG TERM...VORST AVIATION...CMC