Area Forecast Discussion
Issued by NWS Paducah, KY
Issued by NWS Paducah, KY
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609 FXUS63 KPAH 072336 AFDPAH Area Forecast Discussion National Weather Service Paducah KY 636 PM CDT Tue May 7 2024 .KEY MESSAGES... - Remain weather aware today through Wednesday evening as multiple rounds of severe weather are expected, and the potential exists for a higher end storm system Wednesday. - Scattered showers and thunderstorms are expected to develop from mid-afternoon through the evening, with some of these storms strong to severe. - Storms begin again Wednesday morning as a warm front lifts northward. A more significant and widespread severe thunderstorm outbreak is expected as a storm complex moves across the forecast area later in the day Wednesday, with a cold front bringing additional storms in the evening. - Repeated rounds of heavy rainfall can result in localized flooding issues, with the highest chances Wednesday afternoon and evening. - Cooler and drier air moves in for the end of the week and weekend with highs in the 70s and lower humidity. && .DISCUSSION... Issued at 304 PM CDT Tue May 7 2024 Following the morning storms, skies have remained mostly cloudy across the Quad State region. Despite the patches of cloud cover, temperatures have risen to the upper 70s to the lower 80s. The first initial afternoon showers have struggled to get going, with better convection north of the forecast area. The environment has many robust parameters this afternoon. SBCAPE above 3000 with MLCAPE above 2000-2500 provides plenty of instability. 0-6km shear is around 60 kts (higher to the northwest outside the CWA), and STP is at 3-4, while 0-3 km shear is 20-35 kts for now. While dew points are near 70, storms are not firing at this time. One parameter that is lacking is mid-level lapse rates which are around 6-6.5 C/km and slight capping is present around 850 mb. The right exit region of the jet is near I-64 at this time, also limiting development, but should shift away to the northeast by the evening. Models focus late afternoon development further near the I-64 corridor with surface convergence near St Louis on satellite, though storms are possible elsewhere. These storms are more likely to take the form of discrete cells/supercells. For the evening hours, the more favorable development will be near and south of the Ohio River, with a more patchy linear development. All severe hazards remain possible with these storms, albeit with hail potential skewed more towards the afternoon hours rather than later in the evening. Flooding potential today is fairly limited, as long as any linear development this evening progresses southward. This rainfall would set the stage for tomorrow. For the overnight hours, a brief break in rainfall is anticipated. Partial clearing, especially in the north, could allow for brief development of patchy fog with calm winds. The cold front stalls out overnight, reversing course back north during the morning as a warm front as low pressure tracks northeastward from Oklahoma towards St Louis. Models differ in positioning, strength, and timing, but are better aligned on morning convection developing with the warm front. Strong to severe storms are possible, more likely later in the morning. After these repeated rounds of storms today and tomorrow morning, the main event is likely to be a robust squall line moving through during the afternoon hours tomorrow. Supercells are possible ahead of the squall line which, depending on morning activity, may encounter a clear warm sector environment suitable for a sustained track. Models differ on whether the afternoon MCS remains connected with the cold front in Arkansas or surges out ahead. CAPE is roughly as high as today, and more robust helicity and shear are expected along with mid-level lapse rates rising to around 8C/km, providing a much more favorable environment if the morning storms progress far enough to allow for recovery before the afternoon MCS. The main MCS should limit any follow up storm development but portions of SEMO or Western Kentucky that stay just south of the afternoon storms will have better lingering potential for the evening. All hazards are on the table, including significant wind or strong tornadoes. With the warm front in the morning, and robust storm activity in the afternoon, along with prior rainfall, localized flooding issues are likely to develop Wednesday. Exact positioning is limited due to uncertainty in warm front location and stalling potential. Cooler and much drier air surges in Wednesday night following the front. More seasonal temperatures are expected for the end of week and weekend with fairly dry weather as most models keep a Great Lakes system to our northeast for the weekend. A Four Corners system tracks eastward, returning PoPs to the forecast early next week. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 629 PM CDT Tue May 7 2024 Convection is struggling to get going this evening; however, not completely out of the question to have a few showers and storms over the next two to three hours. Gusty winds and heavy downpours will be the main threats along with brief MVFR conditions. A break can be expected in any convection overnight, but some fog may form, especially where rainfall occurs. A warm front will lift north through the area Wednesday bringing more widespread chances for showers and storms early in the afternoon and especially toward the evening hours. Severe weather with gusty winds and hail will be possible. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ DISCUSSION...ATL AVIATION...KC