Convective Outlook
— Day 2
Summary
Isolated to widely scattered strong to severe thunderstorms may pose a risk for damaging wind gusts across portions of the southern Appalachians to the coastal Carolinas/southeast Virginia vicinity on Sunday. Strong to severe storms may also develop across parts of eastern Montana into North Dakota and Minnesota.
Southern Appalachians To The Coastal Carolinas/Southern Va ?
An upper trough over the eastern U.S. will persist on Sunday. At the surface, a cold front will develop southward across VA toward the NC/VA border. Near and south of this front, a very moist airmass will be in place (70s F dewpoints), and strong heating will foster a corridor of moderate instability. Deep-layer flow will remain modest, with effective shear values typically only around 20-25 kt. However, steep low-level lapse rates and PW values near/above 2 inches are present in forecast soundings. Storms that develop will pose a risk for wet microbursts, and a greater wind risk may evolve closer to the cold front where sufficient clustering occurs.
Northern Plains Into Northern Mn ?
A compact upper low/shortwave trough over Alberta will develop east/southeast on Sunday, emerging over the Canadian Prairies and northern Plains. As this occurs, a belt of strengthening west/northwesterly mid/upper flow will overspread the region. A surface cold front will develop southeast across eastern/southern MT during the afternoon, and the Dakotas during the evening/overnight hours. Southerly low-level flow ahead of this feature will transport modest moisture northward into the area. Steep midlevel lapse rates will support 1000-2000 J/kg MLCAPE amid 40+ kt effective shear magnitudes. Initial convection may be cellular, posing a risk for isolated large hail. Given steep low-level lapse rates, strong outflow winds also will be possible, and some potential for a bowing cluster of storms is possible if sufficient storm coverage occurs ahead of the cold front from southern/eastern MT into the Dakotas through evening. Overnight storms may persist eastward into northern MN, though severe potential is less certain across this area given stronger capping.
000 ACUS02 KWNS 180507 SWODY2 SPC AC 180505 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1205 AM CDT Sat Jul 18 2026 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN PLAINS...AND PARTS OF NORTH CAROLINA INTO SOUTHEAST VIRGINIA... ...SUMMARY... Isolated to widely scattered strong to severe thunderstorms may pose a risk for damaging wind gusts across portions of the southern Appalachians to the coastal Carolinas/southeast Virginia vicinity on Sunday. Strong to severe storms may also develop across parts of eastern Montana into North Dakota and Minnesota. ...Southern Appalachians to the Coastal Carolinas/Southern VA... An upper trough over the eastern U.S. will persist on Sunday. At the surface, a cold front will develop southward across VA toward the NC/VA border. Near and south of this front, a very moist airmass will be in place (70s F dewpoints), and strong heating will foster a corridor of moderate instability. Deep-layer flow will remain modest, with effective shear values typically only around 20-25 kt. However, steep low-level lapse rates and PW values near/above 2 inches are present in forecast soundings. Storms that develop will pose a risk for wet microbursts, and a greater wind risk may evolve closer to the cold front where sufficient clustering occurs. ...Northern Plains into northern MN... A compact upper low/shortwave trough over Alberta will develop east/southeast on Sunday, emerging over the Canadian Prairies and northern Plains. As this occurs, a belt of strengthening west/northwesterly mid/upper flow will overspread the region. A surface cold front will develop southeast across eastern/southern MT during the afternoon, and the Dakotas during the evening/overnight hours. Southerly low-level flow ahead of this feature will transport modest moisture northward into the area. Steep midlevel lapse rates will support 1000-2000 J/kg MLCAPE amid 40+ kt effective shear magnitudes. Initial convection may be cellular, posing a risk for isolated large hail. Given steep low-level lapse rates, strong outflow winds also will be possible, and some potential for a bowing cluster of storms is possible if sufficient storm coverage occurs ahead of the cold front from southern/eastern MT into the Dakotas through evening. Overnight storms may persist eastward into northern MN, though severe potential is less certain across this area given stronger capping. ..Leitman.. 07/18/2026 $$