SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Mar 27 2025 Valid 271630Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR THE LOWER MISSOURI VALLEY... ...SUMMARY... Isolated to scattered large hail and localized severe wind gusts are possible across parts of the Lower Missouri/Mid-Mississippi Valleys. ...Central Plains to Lower Missouri/Middle Mississippi Valleys... Scattered thunderstorms, including a few lingering strong storms, continue late this morning from eastern KS into northern MO within a warm-air advection regime. Morning raob data over the central Great Plains indicated the northeastern periphery of the EML is located over the lower MO Valley. Strong heating in wake of the early day convection will result in moderate buoyancy developing into northeastern KS later this afternoon. Models show a flattening mid- to upper-level ridge through tonight. Nebulous/weak forcing at best is expected in the vicinity of a warm front/outflow intersection later this afternoon. However, the erosion of CINH may enable a few isolated thunderstorms to develop late this afternoon into the evening. Recent HRRR runs and the 12 UTC model-run members of the HREF show a dearth of storm development. Confidence in appreciable storm coverage is lowering for diurnally based storm initiation and casting uncertainty in terms of the potential severe threat. Nonetheless, supercellular development could occur in the presence of moderate instability and favorable wind profiles featuring around 35-40 kt effective shear magnitudes. A greater coverage of elevated storms may occur tonight as the low-level jet reestablishes and storms expand eastward regionally. Large hail is the most probable hazard in both regimes. ...South Texas... Visible-satellite imagery shows an extensive cloud shield and convective cloud debris across much of south TX into the upper coast, and farther west into the Big Bend region. This is in response to a slow-moving upper trough which is forecast to move across northern Mexico toward Deep South Texas by Friday morning. This episodic convection across northern Mexico into adjacent portions of TX should limit heating during the day. Forecast soundings show seasonably moist profiles from the surface through the mid levels subduing lapse rate magnitudes. Mid-level flow will translate through the base of the trough, south of the international border into the lower Valley of Texas by early evening. However, considerably weaker flow with north extent (i.e., Edwards Plateau) and uncertainty regarding destabilization farther north cast uncertainty on storm intensity across south-central TX. The low-level jet will remain focused across south Texas aiding in regenerative storm development and an occasional isolated severe threat may occur with the stronger storms. ..Smith/Jewell.. 03/27/2025