792 FXUS63 KLMK 140712 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 312 AM EDT Mon Apr 14 2025 .KEY MESSAGES... * Severe thunderstorms will be possible this afternoon across the Bluegrass region of central Kentucky. * The primary severe weather threats will be large hail, damaging winds, and a risk of isolated tornadoes. * Cooler and dry conditions are expected for the middle of the week before warmer temperatures returns late this week. && .SHORT TERM /THROUGH TONIGHT/... Issued at 312 AM EDT Mon Apr 14 2025 Conditions across the region were partly cloudy this morning. A gradient of temperature was noted in observations. Temperatures ranged from the lower 70s over far western KY to the low 60s in the I-65 corridor. OUt east of the I-75 corridor, temperatures were more of a ridge/valley split with the ridges in the upper 50s/lower 60s and valleys in the lower 40s. Breezy southerly winds will continue overnight, but no significant weather is expected through sunrise. After sunrise, daytime mixing will begin in earnest. Surface winds are expected to pick up through the mid-late morning with winds becoming gusty by lunchtime and continuing through the afternoon. Have gone a little higher with temps given the strong southerly wind flow. Plan on going with mid-upper 70s across southern Indiana and much of the northern half of Kentucky with upper 70s and lower 80s across southern Kentucky. During the afternoon hours, attention will turn to convective development ahead of an approaching cold front. Southerly flow across the area today will transport low-level moisture into the region and allow this moisture to pool across much of central and eastern KY. By late afternoon, a mid-level jet streak will approach from the west and much of our region will be within the left exit region of this 80-90kt jet. The combination of the synoptic scale lift with the jet and the cold front should result in scattered to numerous convection firing across portions of the region. For the past several days, the convective signal has been there in the data, with the main concern on whether convection would be able to break through some mid-level capping. The last several runs of the CAMs have been trending stronger with the forcing and weakening this cap, especially in areas east of I-65. Model soundings across the region show rather straight and elongated hodographs with 0-6km shear values in the 55-65 kt range. MLCAPE values increase across the area to 1500-2000 J/kg during the afternoon with the highest values, mainly east of I-65. Lapse rates in the 700-500 mb layer are impressive as well with values of 7-8 C/km. Current thinking is that we`ll see the cap break between 3-5 PM this afternoon, in a zone roughly from Campbellsville northeast to Ashland. Given the thermodynamic and kinematic parameters, multi- cellular and supercells are expected favoring large hail and damaging winds. Depending on updraft strength and localized instability hot spots, some of the strongest cores could produce very large hail. By late afternoon, the low-level jet flow will increase in the I-75 corridor and points east resulting in a low- level flow more prone for tornado production. Eventual upscale growth of convection into linear bow like structures is expected with a damaging wind threat being possible. The highest threat of severe is across the eastern half of our area, roughly east of a line from Louisville to Campbellsville. The current slight risk area from SPC looks good, though I could see some extension of this risk further south and southwest in later outlooks. Convection from the late afternoon should continue to move off to the southeast and weaken with time as the sun sets. Convection many linger over our southern and southeastern sections into mid-evening before dying out. Cooler and somewhat drier air will push into the region tonight with lows falling back into the middle 40s. && .LONG TERM /TUESDAY THROUGH SUNDAY/... Issued at 312 AM EDT Mon Apr 14 2025 Mid-level trough axis will swing through central and eastern KY during the day on Tuesday. This will keep the Ohio Valley under cyclonic northwest flow and allow for cooler air to advect in over the region. A few clouds may build in over the parts of southeast IN, and the Bluegrass during the afternoon with daytime highs below seasonal normals by nearly 10 degrees in the mid/upper 50s across most of our CWA with near 60 along the KY/TN border. Sfc high pressure coming out of the central plains will move over MS/AL on Wednesday as the upper ridge to the west slowly works over the Ohio Valley. This will keep skies clear and allow for increased heights over the region, which will result in slightly warmer temperatures for the middle of the week. Lows Wednesday morning will be chilly, in the upper 30s to near 40 with afternoon highs warming into the low 60s, which are still around 5 degrees below normal for mid April. By the end of the week, sfc high will move off to the east as the upper ridge builds over the eastern half of the CONUS. A lee-side sfc low develops over the Rocky Mountain Front Thursday and then towards the eastern Great Lakes by Friday. A warm front will lift northward during the day on Thursday, mainly over our northwestern CWA. This could result in a couple of showers/thunderstorms across southern IN. Winds will become more southerly advecting in warm moist air from the south. By Friday, as the sfc low works into the Great Lakes, our precipitation chances will depend on where the associated cold front stalls in relationship to the Ohio Valley and southern IN/central KY. Models are trending more westerly with this feature keeping just slight chance of showers/storms along the Ohio River and north into southern IN. It will become much warmer for the end of the week as highs will be in the mid/upper 60s on Thursday with upper 70s and even a few isolated 80s on Friday. Rain showers and a couple of thunderstorms could be around heading into the weekend depending on where the advancing cold front to our west stalls over the region. A second storm system take shape over the TX Panhandle by the end of the weekend and takes a similar path into the Great Lakes by Monday. This would lift the stalled boundary back northward as a warm front and bring another chance of showers to the region. At this point, we are still to far out to get any real details on this scenario. Forecast continues to keep rainfall totals low, (around a half an inch or less), with warm temperatures remaining in the mid 70s. && .AVIATION /06Z TAFS THROUGH 12Z TUESDAY/... Issued at 104 AM EDT Mon Apr 14 2025 For the remainder of the overnight period, the main aviation concern will be low-level wind shear at the TAF sites. Winds may be breezy at the terminals as well with speeds of 12-15kts. After daybreak, LLWS will depart but surface winds will pick up out of the southwest. Wind gusts of 20-25kts will be common through the afternoon. Convection is likely to fire across portions of the region in the afternoon. Convection is most likely to affect our eastern terminals (KLEX/KRGA). However, will continue to keep a PROB30 in at KSDF/KBWG for this forecast. Convection will wane rapidly after sunset with northwest breezes and VFR conditions expected for the remainder of the period. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...None. IN...None. && $$ SHORT TERM...MJ LONG TERM....BTN AVIATION.....MJ