Area Forecast Discussion
Issued by NWS Louisville, KY
Issued by NWS Louisville, KY
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643 FXUS63 KLMK 311714 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 114 PM EDT Fri May 31 2024 ...Updated Aviation Discussion... .KEY MESSAGES... * Dry weather and below normal to normal temperatures expected through Friday night. * Rain and storm chances return for the weekend and continue into next week. Temperatures and dewpoints will also be on a steady increase into next week. && .UPDATE... Issued at 1059 AM EDT Fri May 31 2024 It`s another nice late spring day with high pressure centered over the upper Ohio Valley. All forecast parameters are in good agreement with reality; no significant changes are needed at this time...did slightly knock afternoon dew points down east of I-65. && .SHORT TERM /THROUGH TONIGHT/... Issued at 251 AM EDT Fri May 31 2024 Dry and pleasant weather will continue today as high pressure shifts slightly from the Great Lakes to the Appalachians. However, expect a bit more cloud cover than yesterday, with upper level cirrus increasing later today from the west that is associated with a 500mb shortwave. NBM is a bit aggressive with the cloud cover this morning, so will go against the NBM guidance and keep skycover mostly clear/sunny to start, but will see the cloud cover increase later this afternoon and especially this evening and tonight. Temperatures will reach the upper 70s to around 80. For tonight, expect mostly cloudy skycover as a mid-level shortwave ejects out of Arkansas. It`ll be dry for most of the region tonight, but will introduce a 15-20% PoP after 06z for our counties west of I- 65 as the eastern periphery of the moisture transport axis begins to work into central Kentucky and southern Indiana after midnight. Model soundings show lingering dry air in the lowest 1km between 06- 12z Saturday morning, so perhaps some virga in the predawn hours before we fully saturate the column. Better chances for accumulating precip arrive in the Long Term period. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Issued at 251 AM EDT Fri May 31 2024 After nearly a week of dry weather for most, rain will make a return to the region on Saturday. Models prog modest isentropic lift along ~305K surfaces ahead of a compact shortwave that will tumble into the Ohio and Tennessee Valleys on Saturday. Deeper moisture with Gulf of Mexico origins will be drawn northward ahead of this shortwave, and the combination of lift/forcing in conjunction with the deeper moisture will promote rain shower development as early as Saturday morning. We could see `waves` of rain through the weekend as the shortwave slowly advances eastward. Model soundings over southern IN and central KY show very poor low and mid level lapse rates, indicating that instability will be at a minimum. The lack of instability should keep overall thunderstorm chances low, and any strong/severe storm chances near 0% despite some marginal deep layer shear in the environment. Warmer and more humid conditions return by early next week and will likely continue through at least midweek as the main jet flow/energy stay confined to the northern U.S. Subtle shortwaves could tumble into the region during this timeframe and spark off showers/storms any time of the day or night, but outside of those waves, most precipitation chances will be driven by mesoscale features and likely be highest in the afternoon and early evening hours. A fairly modest upper level trough (by early June standards) and surface cold front looks to pass through the region by late Wednesday or Thursday and should bring a return to cooler temperatures and lower dewpoints by Friday into next weekend. && .AVIATION /18Z TAFS THROUGH 00Z SUNDAY/... Issued at 114 PM EDT Fri May 31 2024 With high pressure over the upper Ohio valley this afternoon surface winds will continue to come in from the ESE around 10kt with a few higher gusts. VFR conditions will continue with cirrus as the predominating cloud type. Tonight a 500mb shortwave trough will approach from the west. Borderline LLWS may materialize at HNB and BWG as a compact low level jet forms over the Tennessee Valley. Ceilings will gradually lower and thicken from west to east, with showers moving into the region by early Saturday morning. Showers will overspread the area during the day, with some scattered thunder possible especially in the afternoon. Will stick with mostly VFR conditions although some MVFR ceilings and vsbys may form once the showers move in tomorrow. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...None. IN...None. && $$ UPDATE...13 SHORT TERM...CJP LONG TERM...DM AVIATION...13