FXUS64 KMEG 181131 AFDMEG Area Forecast Discussion National Weather Service Memphis TN 631 AM CDT Thu Apr 18 2024 ...New AVIATION... .SYNOPSIS... Issued at 310 AM CDT Thu Apr 18 2024 Severe weather chances begin to increase this afternoon. Damaging winds and large hail are the primary threats. A secondary round of severe storms is anticipated this evening, but confidence is low due to arrival time and atmospheric stability. Wet conditions will continue through the weekend before high pressure slides in. Sunday and Monday will be much cooler and drier to start the work week. && .DISCUSSION... (Today through Wednesday) Issued at 310 AM CDT Thu Apr 18 2024 An upper-level trough will move through the north-central U.S. today. Concurrently, a surface low will move through Missouri as a cold front advances into the Ozarks. Warm and moist air aided by surface heating will enhance discrete cell development this afternoon. Over the Mid-South, 0-3km lapse rates are steep (~8 C/km), 30-40kts of 0-6 km bulk shear also aided by low-level convergence, may result in strong to severe storms this afternoon prior to the main line arrival. HREF probabilities of CAPE >2000 J/kg peak near 3 PM at around 30-50% while probabilities of CAPE >1500 J/kg are around 80%. Depicted on mid-level GOES water vapor imagery, a pocket of dry air aloft and near 70 degree dewpoints at the surface, may aid in intensification of updrafts this afternoon. Confidence is lower than desired, but deterministic soundings are indicative of an environment supportive of severe weather. A line of storms associated with the upper level trough looks to approach the Mid-South this evening around 7 PM. The impacts associated with this line are limited due to timing and atmosphere stabilization. From previous forecasts, a cold pool over Missouri looks to develop earlier than anticipated putting more of focus on the afternoon round. Damaging winds and large hail look to be the primary threats for the afternoon round as SRH values are low (less than 50 m^2/s^2) with not much curvature is noted in low level hodographs. If the atmosphere remains unstable for the evening line of storms, damaging winds and hail are still the primary threats. Although low-level shear is not forecast to be that strong, a few QLCS tornadoes will be possible (as there is an uptick of SRH values) with rotating cells embedded within the line. A brief lull in shower activity is expected Friday afternoon for most of the region. Another round of showers and thunderstorms approaches on Saturday. Thunder chances remain low as surface temperatures will be on the cooler side in the mid 60s. After this round of showers, high pressure will gradually begin to slide in by Sunday to return rainfree conditions. Cooler temperatures are associated with the high as lows Sunday and Monday morning are forecast to be in the 40s. Monday will feel much cooler as dry air and brisk northerly winds will prevail. Temperatures will begin to warm back to near and above climatology early next week. DNM && .AVIATION... (12Z TAFS) Issued at 619 AM CDT Thu Apr 18 2024 Challenging TAF period with significant low-level moisture streaming up from the south. IFR ceilings expected to lift to MFVR and VFR by mid-day and winds will become gusty out of the SSW. By early afternoon strong to severe TS expected. Later in the evening and overnight, expecting a broken QLCS to move across all terminals and ceilings will drop to IFR again. Winds will quicklty shift around to the northwest with frontal passage. IFR to possible LIFR will persist into the daylight hours on Friday. DKJ && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$ PUBLIC FORECAST...DNM AVIATION...DKJ