FXUS64 KMEG 042026 AFDMEG Area Forecast Discussion National Weather Service Memphis TN 326 PM CDT Sat May 4 2024 ...New SYNOPSIS, DISCUSSION... .SYNOPSIS... Issued at 326 PM CDT Sat May 4 2024 Warm and humid conditions will support scattered to numerous showers and thunderstorms through the middle of next week. A few severe thunderstorms will possible on Sunday, as an upper level disturbance lifts from Texas into the lower Mississippi River Valley. Severe thunderstorm chances will increase by midweek, ahead of a deep upper level low pressure system moving through the Great Plains and mid-Mississippi River Valley. A cold frontal passage on will bring cooler and less humid conditions to the Midsouth by next weekend. && .DISCUSSION... (This evening through next Friday) Issued at 326 PM CDT Sat May 4 2024 An active weather pattern is ahead for the Midsouth through the middle of next week. A convectively- enhanced shortwave will lift from west central Texas into the western Ozarks by midday Sunday. Mixed layer CAPE over the Midsouth will increase to 1000-1500 J/kg. 0-6km bulk shear will prevail at 20-30kt, relatively modest but about double that of today. This will support a marginal severe threat by midmorning Sunday. Damaging winds, hail and heavy rainfall appear to be the primary threats. Given the projected timing of the shortwave, storms should exit and/or diminish by Sunday evening. Monday should be relatively quiet under shortwave ridging. But the ridge axis will be east of the area Monday evening, opening the door for storms to enter the Midsouth from southern AR, aided by a 40kt low level jet. Severe thunderstorms are appearing more likely Tuesday and Wednesday, aided by height falls associated with a deepening northern branch longwave trough over the western two-thirds of the CONUS. Low level return flow will strengthen in response, driving surface dewpoints to around 70F over the Midsouth. The increased low level moisture will drive surface-based CAPE in excess of 2500 J/kg Tuesday afternoon, accompanied by 0-6km bulk shear around 45kt north of I-40. With strong southerly flow continuing, the lower atmosphere should recover Wednesday from Tuesday night storms. An upper level trough axis, pendant from a closed low over eastern Nebraska, will pivot through the Ozarks Wednesday afternoon and evening, driving height falls and enhancing frontal convergence over the lower Ohio River Valley and Midsouth. Surface-based CAPE will peak around 3000 J/kg Wednesday afternoon, before moderating below a still impressive 1500-2000 J/kg Wednesday evening. GFS and ECMWF mean 700-500mb lapse rates are progged at an impressive 8 C/km Wednesday afternoon and evening. Given the projected CAPE, this would be supportive of very large hail, at least during the afternoon. Given the tendency for prefrontal veering of low level winds, convection may transition to a linear mode Wednesday evening, perhaps reducing the large hail and tornado threat, but enhancing the flash flooding threat. Projected PWAT is around 2 inches, about as high as it gets this time of the year. Quieter weather should prevail Thursday, following the passage of the convectively-reinforced cold front. Another cold frontal passage appears likely on Friday, as a deep longwave trough sets up briefly over the eastern CONUS. This should bring relatively cool and dry conditions to the Midsouth next weekend. PWB && .AVIATION... (18Z TAFS) Issued at 1220 PM CDT Sat May 4 2024 A cluster of showers and thunderstorms, currently situated over Arkansas, will push into the Mid-South over the next several hours. Most recent CAMs are struggling to account for this activity, so TS timing in TAF is based on estimated time of arrival from radar. Overnight, winds will go variable or calm at all sites, which may encourage fog development at MKL, TUP, and JBR. Towards the end of the period, another round of showers and thunderstorms looks to impact MEM. ANS && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$ PUBLIC FORECAST...PWB AVIATION...ANS