BBS: TELESC.NET.BR Assunto: DAY1SVR: Day 1 Convective Outlook De: COD Weather Processor Data: Tue, 26 May 2026 19:50:18 +0000 ----------------------------------------------------------- ACUS01 KWNS 261950 SWODY1 SPC AC 261948 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0248 PM CDT Tue May 26 2026 Valid 262000Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF CENTRAL INTO DEEP SOUTH TEXAS... ...SUMMARY... Scattered severe thunderstorms appear possible this afternoon and evening across parts of southwest into south-central Texas. Large hail, severe wind gusts, and a couple of tornadoes may occur. ...20Z Update... Much of the forecast remains generally on track. Across central into southern Texas, Slight risk probabilities were trimmed from the west to account for the passage of an ongoing MCS. Severe probabilities were increased into deep south Texas for the possibility of preceding supercells developing ahead of the eastward-meandering MCS this evening, which may be accompanied by a severe wind/hail threat. Finally, 5 percent wind probabilities were expanded eastward across MT, and farther west from the Midwest into ND, to account for trends in both observations and the latest guidance consensus. ..Squitieri.. 05/26/2026 .PREV DISCUSSION... /ISSUED 1129 AM CDT Tue May 26 2026/ ...Texas... Ongoing thunderstorms late this morning across west TX are being aided by ascent associated with a weak mid-level trough over the southern High Plains. While an isolated hail/wind threat may persist with this activity in the short term, expectations are for an increasing severe risk to materialize this afternoon downstream across parts of south-central TX. Recent surface observations and area VWPs show modest low-level east-southeasterly flow occurring across this region, with surface dewpoints generally in the mid 60s to low 70s. Some clearing/cloud breaks are noted on latest visible satellite imagery, and filtered daytime heating of this moist low-level airmass combined with modestly steepened mid-level lapse rates (reference 12Z observed DRT sounding) will aid in the development of moderate to locally strong MLCAPE by mid afternoon. While low-level flow should remain modest, strong veering of the winds with height through mid/upper levels and a gradual increase in magnitude associated with the weak mid-level trough will support around 30-40 kt of deep-layer shear across the narrow warm sector. A mix of supercells and multicell clusters should spread from northern Mexico/west TX into southwest/south-central TX through the afternoon and early evening. Large hail will be possible with any sustained supercells, while severe/damaging winds may occur with clusters as low-level lapse rates become steepened with continued daytime heating. The tornado threat remains less clear, as modest low-level flow and muted effective SRH suggest low-level mesocyclones may struggle. Still, some risk for a couple of tornadoes remains apparent across a small part of southwest TX. Severe probabilities have been adjusted to account for both ongoing convection and the potential for one or more clusters with some wind threat to persist this evening/overnight across south-central into coastal TX. ...Upper Midwest... A weak/dissipating MCV will move into parts of the Upper Midwest today, as modest westerly mid-level flow continues to the north of a mid/upper-level anticyclone centered over the northern Plains into IA. A weak surface front will remain draped generally west to east from eastern ND into central MN/WI through the day. South of this front, diurnal heating of a seasonably moist low-level airmass will support moderate instability by mid afternoon. While large-scale ascent is expected to remain fairly weak/nebulous, the remnant MCV may foster isolated to scattered thunderstorm development this afternoon and early evening along/near the front. Around 20-30 kt of deep-layer shear should be sufficient for some updraft organization. Isolated large hail and severe/damaging winds may occur with loosely organized multicells and marginal supercell structures, before this activity eventually weakens this evening with the loss of daytime heating. ...Northern Rockies/High Plains... A closed upper low over western OR/northern CA this morning will continue to move slowly southward through the period. A belt of modestly enhanced southerly mid-level flow will exist of parts of the interior Pacific Northwest into the northern Rockies and adjacent High Plains. Even though low-level moisture will remain limited, the boundary layer is forecast to become very well mixed with daytime heating. High-based showers/thunderstorms that develop across this region will spread northward through the afternoon and evening, and may pose an isolated threat for severe gusts and perhaps some hail. ...Ohio Valley/Southeast... A broad zone of 20-30 kt south-southwesterly mid-level flow will likely remain over much of the Southeast and parts of the OH Valley today. 12Z observed soundings from across these regions show poor lapse rates and generally saturated profiles aloft, which should temper the degree of instability which develops this afternoon with filtered daytime heating. Due to the expected thermodynamic limitations, it remains unclear how productive thunderstorms will be in producing damaging winds. Water-loaded downdrafts capable of producing occasional strong to locally damaging winds appear possible across a broad area of the lower/mid OH Valley into much of the Southeast, especially where low-level lapse rates can become at least modestly steepened. However, a more focused corridor for a tornado and damaging winds may exist this afternoon across KY, in closer proximity to a weak mid-level perturbation noted on visible satellite imagery over the Mid-South and a subtle surface boundary. For now, have opted to expand the Marginal Risk to include more of KY, but additional expansions may occur across parts of the Southeast if mesoscale corridors of isolated damaging wind potential can be delineated. ...Northern Maine... A mid-level trough with attendant strong (40-50+ kt) westerly jet will move eastward across Quebec today, and will impact parts of ME this afternoon/evening. Most guidance suggests that a band of thunderstorms will spread quickly eastward across northern ME later today in a weakly unstable but strongly sheared environment. Isolated severe/damaging winds may occur with this activity. $$ = = = 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]