BBS: TELESC.NET.BR Assunto: DAY1SVR: Day 1 Convective Outlook De: COD Weather Processor Data: Tue, 28 Apr 2026 06:01:49 +0000 ----------------------------------------------------------- ACUS01 KWNS 280601 SWODY1 SPC AC 280559 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Tue Apr 28 2026 Valid 281200Z - 291200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF NORTHERN TEXAS INTO THE LOWER MISSISSIPPI VALLEY... ...SUMMARY... Multiple rounds of strong to severe thunderstorms are likely across parts Texas into the lower Mississippi and Tennessee Valleys this afternoon and evening. Very large hail, swaths of damaging wind, and a few tornadoes are possible. ...Synopsis... A series of mid-level troughs, embedded within a broader low-amplitude mid-level flow regime, will traverse the central U.S. today. A surface low and associated cold front will continue to progress across the OH Valley toward the East Coast during the day. However, the approach of another mid-level trough over the Ozark Valley region will encourage either a weak surface low or surface trough to develop over central TX. This will stall the southward progression of the surface cold front given appreciable low-level warm-air/moisture advection. Seasonally cold air aloft and accompanying upper support from multiple embedded mid-level perturbations will overspread the warm-air advection regime, supporting several rounds of thunderstorms. Given strong vertical wind shear over the warm sector, severe storms are likely, especially over portions of the southern Plains toward the TN Valley. ...Portions of northern TX into the TN Valley... A complex severe weather scenario is expected across TX into the TN Valley through the period, with multiple rounds of severe thunderstorms likely. The first round of storms is currently initiating over western TX, and may increase in coverage between 12-18Z across central OK into northern TX as a lead mid-level impulse traverses a WAA regime. 7-8 C/km mid-level lapse rates amid 50+ kts of effective bulk shear will support elevated multicells capable of producing severe hail. These storms will progress across the MS Valley through the day. Some guidance indicates that these storms may evolve into an MCS by afternoon, accompanied by a damaging gust threat over the Gulf coast states. Regardless of the evolution of earlier storms, guidance consensus depicts adequate clearing behind this initial wave over TX into the Ozark Valley region. Strong surface heating will encourage surface temperatures to reach 90 F in some locales, amid 70+ F surface dewpoints. Given 8-9 C/km mid-level lapse rates, MLCAPE should reach the 2500-4000 J/kg range by mid to late afternoon. By this time, the primary mid-level trough will overspread the southern Plains, promoting enough deep-layer ascent for another round of storms to initiate. Given 50 kts of effective bulk shear and initially straight hodographs, supercells are expected, accompanied by a severe hail threat. The most intense supercells may develop over northern TX and progress eastward, and will be capable of producing severe hail as large as 3-4 inches in diameter. Given a lingering low-level jet (supporting elongated hodographs with some low-level curvature) over the Sabine River Valley, a few dominant/right-moving supercells may produce a few tornadoes, though the tornado threat will be conditional on adequate boundary-layer mixing/destabilization. Later in the afternoon/early evening, severe hail/isolated tornado producing supercells may merge into an MCS, accompanied by a severe wind threat across the Lower MS Valley. ...Portions of central into southern TX... Forcing for ascent will be weak across portions of central into southwestern TX. Nonetheless, 8-9 C/km mid-level lapse rates will overspread a well-mixed boundary layer. Tropospheric speed shear exceeding 40 kts will yield elongated hodographs, so any storm that can initiate, mature, and sustain itself should be supercellular in nature, accompanied by a severe hail threat. Any instance of hail with these storms may include stones exceeding 2 inches in diameter. Since a second, low-amplitude mid-level impulse will overspread western and central TX toward the end of the period, isolated supercell initiation will be possible across portions of central into southwestern TX late this afternoon into early (12Z) Wednesday morning. ..Squitieri/Moore.. 04/28/2026 $$ = = = To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.28-Linux * Origin: Capitol City Online (1:2320/107) ----------------------------------------------------------- [Voltar]