Area Forecast Discussion
Issued by NWS Louisville, KY

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581 FXUS63 KLMK 230511 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 111 AM EDT Sun Jun 23 2024 .KEY MESSAGES... * Scattered showers and storms possible Sunday, and again by the middle of next week. Gusty winds the primary threat in any stronger storms that develop. * Heat Index may rise above 100 degrees on Tuesday, especially west of the I-65 corridor. && .UPDATE... Issued at 728 PM EDT Sat Jun 22 2024 Current radar shows a few isolated showers continuing to push NE through the CWA, but these are slowly dissipating as we lose heating. Expect a quiet, yet warm, night as lows only fall into the low to mid 70s. Going forecast remains on track with no major updates needed this evening. && .SHORT TERM /THROUGH MONDAY/... Issued at 304 PM EDT Sat Jun 22 2024 It`s another hot and humid afternoon with temperatures as of 2pm at or just above 90 degrees with dew points near 70 making it feel like the mid/upper 90s. The forecast is still on track for locations to see heat index values over 100 later this afternoon. Along with the heat we`ve seen the development of scattered cumulus and even a few isolated showers. SBCAPE is 1000-2000 J/kg with steep low-level lapse rates but mid-level lapse rates really fall off and any activity that gets started dissipates as quickly as it got started. Most will remain dry but can`t rule out a very brief isolated shower/storm this afternoon into the early evening before sunset. The overnight will remain dry, muggy and warm as the focus in the short term turns to a weak shortwave trough and associated sfc low working across the Great Lakes overnight into tomorrow. Hi-res models continue to show the development of a convective line of showers and storms across northern IL into western MI this evening ahead of an approaching cold front. As this convective system quickly works east and south, it will outpace the best forcing dynamics and dissipate as it works towards southern IN and the Ohio River by daybreak tomorrow. By the time this activity arrives between 10-12z tomorrow, expected a few scattered showers and embedded thunderstorm across southern IN/north central KY before dissipating into central KY. Lows will remain warm tomorrow morning only dropping into the low/mid 70s. Residual outflow left over from the morning activity as well as the arrival of the weak sfc boundary will help to develop more convection late morning into the afternoon. With highs once again approaching the upper 80s to near 90 and dew points in the low 70s SBCAPE will be between 1500-2500 J/kg. SPC has most of our area in a marginal risk for strong to severe storms with hail and gusty winds being the main threat with deep layer shear values marginal or under 30kts but DCAPE over 1000 J/kg. A lot of this activity will depend on how well we clear out from the morning activity and how our low/mid level lapse rates recover in the afternoon. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... Issued at 304 PM EDT Sat Jun 22 2024 High pressure overhead will bring us dry weather once the Sunday evening showers/storms dissipate and move out. With clearing skies and light winds, after possible scattered Sunday afternoon/evening rain, we may see some valley fog by sunrise Monday, especially in the Lake Cumberland region. During the day on Monday, while it will be another very warm day with highs around 90, dew points behind the Sunday front will be slightly more comfortable in the low-mid 60s. That minor relief will be short-lived as moisture returns on Tuesday behind the departing high. A weak 5H shortwave trough over the Midwest and surface cold front will approach from the northwest by afternoon/evening. There will be plenty of instability available and while shear and mid-level lapse rates won`t be impressive, and the forcing will remain rather far off to our northwest, isolated heat- of-the-day summertime thunderstorms can`t be ruled out especially in the evening in southern Indiana closer to the forcing to our north. The bigger story on Tuesday will likely be the heat. With dew points edging back up a few degrees, possibly over 70 west of I-65, and temperatures rising into the lower and middle 90s, the afternoon heat index should touch 100 along and west of I-65. The Tuesday front will push through our area Wednesday and Wednesday night, bringing us our best shot at rain over the next 7 days as surface dew points rise into the lower 70s. Instability and shear will once again not be particularly strong, but with frontal forcing and some upper level divergence under the entrance region of a slightly enhanced upper jet from Ohio to the St Lawrence Valley, some stronger storms will be possible. Right now general QPF for Wednesday-Wednesday night is around a third to half an inch, but amounts will vary given the convective nature of the precipitation. Dry weather will return Thursday and Friday as high pressure advances form the Great Lakes to New England. Forecast data have been trending warmer recently for these two days, with highs around 90 on Thursday and in the low-mid 90s Friday. Saturday a cold front will approach from the northwest, but there are timing differences in the model output. As of now the consensus seems to be that the front will still be pretty far away on Saturday, with a better chance of fropa, and rain, on Sunday. && .AVIATION /06Z TAFS THROUGH 12Z MONDAY/...
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Issued at 109 AM EDT Sun Jun 23 2024 A line of showers and storms have developed ahead of a frontal boundary stretching from northern Missouri into the Great Lakes region. This activity will steadily approach us this morning, but greatly weaken and likely dissipate somewhere over southern Indiana and/or northern Kentucky shortly after dawn. Winds will pick up shortly after sunrise from the southwest, and gusts ~20kts will be common at all TAF sites. Renewed scattered shower/storm development will occur along the frontal boundary and other mesoscale boundaries across our region this afternoon, mainly south of the Ohio river. Any TAF site that is impacted by one of these showers or storms will see briefly reduced cigs/vis and potentially gusty, erratic winds. Winds will turn northwest behind the front and drier air will filter in behind the front this evening giving way to mostly clear skies.
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&& .LMK WATCHES/WARNINGS/ADVISORIES...
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KY...None. IN...None.
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&& $$ UPDATE...CRG SHORT TERM...BTN LONG TERM...13 AVIATION...DM