Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jun 12 2025 19:53:58 ACUS01 KWNS 121953 SWODY1 SPC AC 121952 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Thu Jun 12 2025 Valid 122000Z - 131200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL PLAINS... ....SUMMARY... Scattered areas of severe thunderstorm development are possible today into tonight, accompanied by potential for severe hail and wind across parts of the Great Plains, the Upper Midwest, the Texas coastal plain into the Lower Mississippi Valley, as well as a portion of the northern Mid-Atlantic. ....20z Update... The primary change for this update is to remove risk probabilities across parts of eastern TX and western LA in the wake of a gradually strengthening convective band/MCS where conditions have stabilized. Low-end risk probabilities have been expanded slightly across south TX to account for the southeastward propagation of a convective cluster developing on the outflow of the prior MCS. Recent RAP mesoanalysis estimates/forecast soundings suggest the downstream convective environment may be supportive of organized convection through early evening. Elsewhere, the forecast largely remains on track with few adjustments required. Convection developing within the upslope flow regime across the central High Plains should increase in coverage and intensity as ascent associated with a weak mid-level perturbation (currently over northern UT) overspreads the region. Across the Northern Mid-Atlantic/Northeast, temperatures have warmed into the mid-80s, which should minimize inhibition based on forecast soundings; however, satellite imagery continues to show meager vertical development of cumulus along the frontal zone, which limits confidence in convective initiation and the overall severe threat. See the previous discussion (below) and MCD #1260 for additional details. ...Moore.. 06/12/2025 ..PREV DISCUSSION... /ISSUED 1151 AM CDT Thu Jun 12 2025/ ....North-central Plains including Nebraska/South Dakota... A low-amplitude shortwave trough and associated speed max will progress eastward over the northern High Plains, from southeast Montana/northeast Wyoming toward the Dakotas. Related forcing for ascent and a moderate belt of mid-level westerlies will overlie a wavy frontal zone across southern South Dakota and western Nebraska. At least widely scattered thunderstorms are expected into mid/late afternoon, with moderate buoyancy and 35-45 kt effective shear (especially northern Nebraska northward) supportive of supercells. Large hail and severe-caliber wind gusts are the primary hazards. ....South/East Texas to Lower Mississippi Valley/Mid-South... An extensive MCS and prominent outflow remain primary forecast factors today, with outflow now having progressed off the middle/upper Texas coast. An enhanced low/mid-level wind field on the eastern periphery of the convectively augmented upper low will continue to contribute to some supercell/tornado risk within a moist environment, although cloud cover and thermodynamic limitations may persist. Damaging winds may also occur on a sporadic/relatively limited basis regionally. ....Southeast/southern Appalachians... Strong heating is expected today across parts of Georgia into the Carolinas, where temperatures in the upper 80s F and dewpoints near 70F are forecast. This will lead to widespread moderate CAPE values and the development of scattered afternoon thunderstorms. Vertical shear is weak, but a few weakly organized thunderstorm clusters may reach severe intensity with gusty/damaging winds. ....Northern Mid-Atlantic/Northeast... With full insolation, moderate destabilization will steadily develop this afternoon near/south of a southward-moving front. While ingredients are severe-storm supportive, the extent of deep convective development may be limited by modest overall forcing/low-level convergence, but at least isolated damaging winds/hail will be possible where storms do develop. Favorable deep-layer shear (40+ kt effective) is conditionally supportive of well-organized storms including supercells. In a relative sense, severe storm development currently appears most probable across eastern Pennsylvania, northern New Jersey, and potentially toward the Great NYC Metro vicinity/far southeast New York. $$ = = = 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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .