Area Forecast Discussion
Issued by NWS Louisville, KY

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755 FXUS63 KLMK 211039 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 639 AM EDT Fri Jun 21 2024 ...Updated Aviation Discussion... .KEY MESSAGES... * Heat continues for the end of the week into the weekend with near-record highs for some locations today and Saturday. * Scattered showers and storms possible Sunday, and again by the middle of next week. && .SHORT TERM /THROUGH TONIGHT/... Issued at 257 AM EDT Fri Jun 21 2024 Synopsis...Strong mid-level ridge will slowly weaken and move south of the Lower Ohio Valley as a Pacific shortwave trough ejects to the north-central US. At the surface, stagnant high pressure will continue promoting dry and hot conditions. Today...Latest satellite imagery reveals mostly clear skies over the forecast area with a few mid-level clouds to the west. The resultant radiational cooling in combination with light winds have allowed saturated conditions at several stations, with some already experiencing visibility reductions due to developing fog. Based on a well-mixed boundary layer yesterday afternoon and current relative humidity inversion profiles from the KY Mesonet, most instances of fog should be light, shallow and mostly focus on river valleys and close to bodies of water. Rest of today will be characterized by hotter temperatures (relative to yesterday) and comparably humid conditions. Therefore, peak heat index values this afternoon will range anywhere from 96 to 102 degF, prompting recommendations to stay hydrated and cool while limiting sun exposure. There is even a chance of tying or breaking record highs at SDF and LEX (see Climate section below for more information). Otherwise, winds will remain light and variable accompany by fair weather cumuli. Tonight...Mostly clear skies are anticipated after sunset with winds starting off calm or light and variable, but a light southwest flow could could kick off the second half of the night as the high pressure moves to the south and the Pacific trough advances across the west. The aforementioned wind change and the well above-average temperature trend increased confidence to raise lows, by several degrees, to the point that some warm min records could be in jeopardy. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Issued at 257 AM EDT Fri Jun 21 2024 Hot and dry weather will continue into Saturday as the region remains under the influence of a strong, elongated upper level ridge that stretches across much of the southern CONUS. Highs Saturday and Sunday will likely climb into the 92-97 degree range, and with dewpoints in the mid 60s to right around 70, this will result in heat indices peaking around 97-102 degrees. The core of this upper level ridge will begin to retrograde westward Sunday as low- amplitude upper level trough swings from the Plains into the Great Lakes region. Our region will receive a glancing blow from it as most of the better forcing and lift stay off to our north, but it will provide some chances for much needed rainfall in the form of scattered showers/storms during the day Sunday. Our upper level trough will begin to deepen over the eastern CONUS on Monday, but elongated ridging centered over the Desert SW and southern Plains will try to nudge back toward the Tennessee and Ohio Valleys. As a result, we really won`t see much in the way of a drop in temperatures with the passage of this trough, and temperatures by Tuesday may even climb back into the mid/upper 90s. One slight piece of good news with the warmup early next week is that dewpoints should drop well into the 60s behind the upper trough with only a gradual build up to higher values by midweek. This will help to off- set the heat indices from getting too terribly high above the air temperatures on Monday and Tuesday. Additionally, by late Tuesday into Wednesday of next week, we may see another upper trough swing into the region and bring scattered showers/storms along with clouds to keep temperatures closer to climo normals. && .AVIATION /12Z TAFS THROUGH 18Z SATURDAY/...
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Issued at 638 AM EDT Fri Jun 21 2024 Discussion...Surface high pressure will maintain VFR conditions over the TAF area today. Fog has been patchy this morning with impactful visibility reductions only at HNB. Winds, for the most part, will remain light and variable with a subtle southwest component starting late tonight.
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&& .CLIMATE... Issued at 257 AM EDT Fri Jun 21 2024 ** Near-Record Heat Potential Mainly for Today and Saturday ** Friday 6/21/2024 Max T Fcst/Record (Year) Louisville: 98/98 (1988) Bowling Green: 97/102 (1933) Lexington: 97/97 (1988) Saturday 6/22/2024 Max T Fcst/Record (Year) Louisville: 97/100 (2022) Bowling Green: 97/102 (1901) Lexington: 96/99 (1988) Sunday 6/23/2024 Max T Fcst/Record (Year) Louisville: 92/98 (1988) Bowling Green: 93/104 (1930) Lexington: 91/96 (1988) Some records may have occurred in multiple years. The latest year the record was tied is displayed. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...Air Quality Alert until 1 AM EDT Saturday for KYZ029>031. IN...Air Quality Alert until 1 AM EDT /midnight CDT/ Saturday for INZ076>079-083-084-089>092. && $$ SHORT TERM...ALL LONG TERM...DM AVIATION...ALL CLIMATE...DM