SPC Mar 16, 2025 1300 UTC Day 1 Convective Outlook
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0740 AM CDT Sun Mar 16 2025 Valid 161300Z - 171200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR WESTERN INTO CENTRAL PENNSYLVANIA... ...SUMMARY... Sporadic damaging wind swaths and a few tornadoes will be the primary threats this morning through dusk across a broad portion of the East. ...OH Valley/northern Middle Atlantic... Water-vapor imagery this morning shows an upper trough over the MS Valley with an embedded mid-level vorticity maximum rotating northeastward over the lower OH Valley. This mid-level feature will be accompanied by an intense belt of flow (110+ kt at 500 mb) shifting eastward across the upper OH Valley/central Appalachians through the day. In the low levels, a surface low over southeast Lower MI will develop northward reaching the Quebec/Ontario border by late afternoon. A moist/weakly unstable warm sector to the southeast of the low will only slightly destabilize through peak heating. Yet, short-term model guidance indicates 200-500 J/kg MLCAPE will develop later this morning across the central Appalachians into the eastern OH/western PA border region. A strongly forced band of convection is forecast to gradually evolve over the upper OH Valley. Largely unidirectional southerly flow and elongated hodographs will support a risk for scattered damaging gusts (55-70 mph) and perhaps a couple of brief tornadoes with this activity. The area of greatest model agreement for a convective line posing a risk for severe appears most likely/concentrated across western into central parts of PA. Farther south, gradual intensification of convection within a weakly unstable airmass will support a risk for damaging gusts and perhaps a tornado or two through early evening. ...Southeast... The southern portion of a mid-level trough will continue east through the lower MS Valley into the Southeast today, as a low-level jet steadily shifts east across north FL through much of SC by mid-late afternoon while gradually weakening south of North Carolina. An ongoing broken band of pre-frontal strong to severe thunderstorms will move east into a weakly unstable airmass (reference the 12 UTC Charleston, SC raob). Prior to a gradual weakening of 850-mb flow by early to mid afternoon, adequately enlarged hodographs within a destabilizing airmass (1000-1500 J/kg MLCAPE across north-central FL with considerably weaker instability over the coastal Carolinas) will support organized storms, including line segments (mainly north) and some supercells (south). Scattered damaging gusts (55-70 mph) and a couple of tornadoes are possible as the severe threat shifts east through the period. ..Smith/Thompson.. 03/16/2025
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