Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
414 ACUS02 KWNS 051730 SWODY2 SPC AC 051728 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 PM CDT Thu Jun 05 2025 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN HIGH PLAINS TO THE TN/LOWER OH VALLEYS...AND ACROSS PORTIONS OF SOUTHERN NEW ENGLAND... ...SUMMARY... Scattered severe thunderstorms are expected from the southern High Plains to the Tennessee and Lower Ohio Valleys on Friday into Friday night. Damaging winds and a couple tornadoes are the main hazards. Large to very large hail is possible over the southern High Plains. Additional severe storms producing damaging wind gusts are possible across portions of southern New England Friday afternoon. ...Central/Southern High Plains into OK... An MCS will likely be ongoing Friday morning across portions of the Ozarks and arcing into parts of OK. The southern end of this convection over the southern Plains will likely weaken during the morning with an outflow reinforced boundary becoming oriented across southern OK into the southern TX Panhandle/South Plains and east-central NM. It is uncertain how far northward this boundary may modify northward through the afternoon. Southerly low-level flow will maintain a very moist airmass (mid 60s to low 70s F dewpoints) near and south of the boundary, with more modest dewpoints (50s to low 60s F) further north from eastern CO/northeast NM into southern KS/northern OK. Moderate westerly flow aloft will persist through the day, with neutral height tendencies until late (after 06z) in the period when some modest height falls are forecast as a shortwave impulse moves east/southeast across the central Rockies into the central Plains. This will aid in the development of a 30-40 kt southwesterly jet across the southern High Plains during the overnight hours. The expectation is that isolated to widely scattered supercells will develop over the higher terrain of southeast CO/eastern NM/far west TX in a moist upslope flow regime as strong heating occurs through the afternoon. Stronger MLCAPE (up to 3000 J/kg) will be confined to the area near the surface outflow where stronger low-level moisture will be focused. Elongated/straight hodographs above 2 km and steep midlevel lapse rates suggest large to very large hail will be possible (greater than 2 inch diameter) in addition to strong gusts. There is some potential convection could organize into a southeast propagating cluster/MCS moving from southeast CO/northeast NM into the northwest OK overnight. Higher outlook probabilities could become necessary if confidence in this scenario increases and as mesoscale details (location of surface outflows) become better resolved. ...Ozarks to TN/Lower OH Valleys... An MCV tied to ongoing morning MCS over the Ozarks will develop eastward into the OH Valley through evening. Morning convection may weaken initially before re-invigoration/redevelopment occurs during the afternoon as the downstream airmass becomes moderately to strongly unstable, aided by strong heating and dewpoints in the upper 60s/low 70s F. Damaging gusts will be the main hazard with this activity, especially if updraft consolidation occurs within storm clusters closer to the MCV where midlevel flow will be enhanced, resulting in some forward propagation. Vertical shear will be more modest with southward extent, but instability will be stronger, supporting at least an isolated severe wind risk into the TN Valley vicinity. ...Portions of southern New England... A weak surface boundary will be draped across portions of New England into central OH Friday afternoon. Ahead of this boundary, rich low-level moisture (mid 60s to low 70s F) dewpoints will be focused in a corridor from eastern PA into MA/CT and southern VT/NH/ME. Strong heating within this corridor will result in a narrow corridor of moderate destabilization (MLCAPE greater than 2000 J/kg). Steepened low-level lapse rates also will foster DCAPE near 1000 J/kg. Vertical shear will remain modest, around 20-25 kt effective shear magnitudes, but strong instability will support strong to severe storms capable of damaging gusts through the afternoon. ..Leitman.. 06/05/2025 $$