212 FXUS63 KLMK 151404 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 1004 AM EDT Thu Aug 15 2024 .KEY MESSAGES... * Stormy weather returns this week, with the highest chance for showers and thunderstorms being Thursday night and Friday. Isolated strong or severe storms could be possible Friday afternoon. && .UPDATE... Issued at 1003 AM EDT Thu Aug 15 2024 Skies are partly cloudy this morning with temperatures warming into the low to mid 70s. A band of convection continues to push east across central and southern IL, but these storms will weaken as they move into a more stable environment over IN. A notable west-to-east moisture gradient is in place across the Lower Ohio Valley, with the main LLJ/moisture transport axis still confined to our west across MO and IL. A few showers may linger into our southern IN counties, mainly west of I-65 this afternoon, but confidence in thunder is low. Otherwise, most will enjoy a dry day with afternoon temps warming through the 80s. && .SHORT TERM /THROUGH TONIGHT/... Issued at 358 AM EDT Thu Aug 15 2024 Today will begin uneventful under mostly clear skies with calm to light and variable winds. This is in thanks to an upper ridge sliding over the region and surface high pressure, centered over Pennsylvania, influencing the Ohio Valley, but just behind the upper ridge, an upper trough is pushing a line of convection through Iowa and Missouri. This line is continuing to weaken, but it could hold together long enough to make it into western Indiana and western Kentucky. This could provide for a few sprinkles this afternoon if it can survive, but not expecting thunderstorms or anything much more than a few drops as model soundings show there isn't much in the way of instability and a dry layer near the surface. We can expect to see increasing cirrus and some mid level clouds as we head into the afternoon hours. The mostly dry, mostly sunny day will lift temperatures into the upper 80s with the possibility of a few places reaching 90. Tonight, as we sit in the warm sector behind the warm front and ahead of an approaching cold front, that's embedded in the upper trough, southern winds will continue to funnel Gulf of Mexico moisture into the Lower Ohio Valley. Dew points in the low 70s will continue working into the CWA from the southwest as precipitable water values approach 2". This will increase shower and thunderstorm chances throughout the night as they become more widespread during the second half of the night. Severe weather isn't expected as model guidance shows limited instability and stable near surface layer. Added sky cover and warm air advection is expected to keep lows in the upper 60s to low 70s. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Issued at 358 AM EDT Thu Aug 15 2024 Friday morning still appears to be the most likely time for heavy and widespread precipitation to move across the region as an axis of 2" PWATs moves through the area. Model guidance continues to show limited instability and shear with high LCLs, so severe weather isn't expected. The best chance for anything stronger or severe would be Friday afternoon, but also believe the chances of this are less than they were yesterday as cloud cover will likely limit instability recovery. There remains some uncertainty on timing with additional shower and thunderstorm chances into the weekend. With the cold front expected to move through the region on Saturday, additional rainfall is expected, but wouldn't count on the whole weekend being a washout as this is summer convection, more scattered in nature. Behind the front, precipitation chances will begin to diminish. High temperatures on Friday are expected to reach into the upper 80s to low 90s before the cold front passes on Saturday, limiting highs on Sunday to the low to mid 80s. These cooler temperatures will last into the middle of next week. From Sunday through the end of the work week, a large upper ridge and surface high pressure will bring a return of dry mostly sunny skies to the Lower Ohio Valley. After the surface high passes east of the region late in the week, slightly warmer temperatures can be expected from southern surface flow. && .AVIATION /12Z TAFS THROUGH 18Z FRIDAY/... Issued at 705 AM EDT Thu Aug 15 2024 The forecast remains on track. VFR conditions are expected through the period. Upper ridging and surface high pressure just off to the northeast are keeping skies mostly clear and winds light, but as we continue through the period, an advancing surface low will increase the pressure gradient over the Lower Ohio Valley, resulting in sub 10 knot winds out of a general southerly direction. High level clouds are also expected to become more dense ahead of approaching upstream convection. Tonight, as the upper trough begins to approach southern Indiana and central Kentucky, shower and thunderstorm chances will begin increasing from the northwest to southeast. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...None. IN...None. && $$ UPDATE...EBW SHORT TERM...KDW LONG TERM...KDW AVIATION...KDW