####018005042#### FXUS63 KPAH 160415 AFDPAH Area Forecast Discussion National Weather Service Paducah KY 1115 PM CDT Thu May 15 2025 .KEY MESSAGES... - Severe weather risk remains highly conditional this afternoon and evening. Isolated storms so far have been elevated with hail being the main concern. If a strong cap can break, all hazards including large hail, tornadoes, and damaging wind would be possible. - A significant severe weather outbreak is likely Friday afternoon into Friday evening. Widespread damaging wind is the greatest risk, but scattered large hail and strong tornadoes will also be probable. - More unsettled weather returns Sunday night through Wednesday with more severe weather potential, especially on Tuesday. && .DISCUSSION... Issued at 305 PM CDT Thu May 15 2025 A broad 500 mb trough ejecting across the central CONUS will cause increasing height falls this evening across the FA. Dewpoints are now in the 70s with MLCAPE between 2000-3000 J/kg. While a cluster of convection has now entered portions of southeast Missouri, a stout EML between 900-825mb is still present on model soundings supporting elevated convection. Given steep 3-6 km lapse rates between 8.0-9.0 C/km and 60-70 kts of sfc-6 km shear, the main concern will be the potential for storms to produce extremely large hail. Confidence still remains low in the ability to erode the cap due to modest synoptic scale forcing for ascent along with how widespread convective spatial coverage will be into this evening. Thermal profiles also indicate a lot of dry air in the column further north which may limit coverage. Overall, the risk remains very conditional, but if storms do manage to become more surface based, all hazards will become probable. Another round of scattered convection will be possible overnight into early Friday morning, but the parameters overall are more marginal for severe weather at best. If coverage this afternoon ends up being more widespread, it may help to push the boundary further south of the FA. With that said, as an embedded 500 mb shortwave digs into IL/MO Friday afternoon as the left exit region of a 250 mb 120-130 kt jet max provides increasing upper level divergence. Robust forcing and lift will cause a residual EML to quickly erode by Friday afternoon, supporting explosive convective initiation. Confidence remains high in a significant severe weather outbreak occurring with SPC's D2 outlook now upgraded to a moderate risk across the entire FA. The parameters are quite alarming for a higher end event with 3000-5000 J/kg of SBCAPE and 60 kts of effective bulk shear. Given a theta-e 3-6 km difference of 30-40K and DCAPE over 1100 J/kg, the greatest concern will be the potential for widespread damaging wind gusts upwards 70-80 mph. While more scattered, the potential for large hail and strong tornadoes will also be fairly significant given steep 3-6 km lapse rates between 7.5- 8.5 C/km, 30-40 kts of sfc-1km shear, 3CAPE around 80 J/kg. Cannot stress enough the potential for strong tornados with STP values around 6 to 8 and sfc-1 km SRH values of 200-300 m2/s2. The only uncertainty is how quickly convective initiation occurs as the 12z CAMs differ by a few hours between 17- 20z. As for the storm mode, storms initially will be more discrete and supercelluar with all hazards before quickly growing upscale into a MCS with a transition to more of a damaging wind and QLCS tornado risk. The only good news is the severe weather risk should be mainly east of the FA by 04z Friday night. After fropa occurs with a cold front, dry and tranquil weather conditions can be expected on Saturday. Another round of unsettled weather quickly returns by Sunday as a warm front lifts back north. Daily chances for showers and storms continue through Wednesday as another 500 mb trough approaches. The pattern remains favorable for more severe weather potential, especially on Tuesday. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1109 PM CDT Thu May 15 2025 Convection is expected to develop overnight, with KCGI/KPAH/KOWB the most likely terminals to be impacted. This activity may linger into Friday morning across west Kentucky before moving out by 14-15z. A lull is expected late morning into early afternoon before additional development in the form of severe storms develops mid-late afternoon and continues into the evening tomorrow. Included PROB30's for the most likely timing of heaviest convection at any one terminals. Will see reductions in cigs/vsbys associated with storms, along with the possibility of very large hail, 70 mph wind gusts, and strong tornadoes. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ DISCUSSION...DW AVIATION...SP