SPC Convective Outlooks
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CDT Fri Jun 05 2026 Valid 051630Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FROM NEBRASKA/KANSAS INTO NORTHERN ILLINOIS...AND FROM CENTRAL MINNESOTA INTO CENTRAL WISCONSIN... ...SUMMARY... Thunderstorms with large hail and severe wind gusts are expected to develop late this afternoon and evening from parts of the central Plains into the mid Missouri and mid Mississippi Valleys. Strong to severe wind gusts and hail will also be possible in parts of the upper Mississippi Valley. ...Central Plains into the Mid MS Valley... Morning surface analysis places a low over northwest KS, near the intersection of weak lee troughing and the western edge of a remnant outflow boundary extending across southern NE. Upper 60s/low 70s dewpoints are already in place east/southeast of this surface low and outflow boundary. Southerly/southeasterly flow will persist throughout the day, maintaining a large fetch of low-level moisture advection from the southern Plains into the Mid MS Valley. Steeper mid-level lapse rates are also emerging out of the central High Plains, spreading gradually eastward over these moist low-levels throughout the day. As a result, a corridor of strong to very strong buoyancy is anticipated from south-central NE/north-central KS along the IA/MO border into far west-central IL by the late afternoon. Expectation is that the outflow boundary will gradually retreat northward while the cold front progresses slowly southeastward across SD and NE. Convective initiation is anticipated along both of these boundaries, beginning over north-central KS/south-central NE near the surface low at the outflow boundary/cold front intersection. Most guidance indicates this initiation will occur after 00Z, but earlier initiation appears possible given moist low-levels, robust heating, and mesoscale convergence. Recent RAP soundings indicate minimal convective initiation by 21Z. Once initiation occurs, strong buoyancy (i.e. MLCAPE over 2500 J/kg) will support intense updrafts capable of large to isolated very large hail. Modest deep-layer shear (i.e. effective bulk shear less than 30 kt) could limit storm organization, with a trend towards a more outflow-dominant mode. The generally modest mid-level flow also suggests upscale growth into an organized convective line is low. Even so, a combination of convergence along the outflow and/or cold front, as well as modest warm-air advection, will contribute to additional storm development eastward into the Mid MS Valley. ...Upper Midwest... Recent surface analysis shows a cold front extending from north-central WI southwestward through central SD. A low exists along this boundary near the ND/SD/WI border intersection. This low is forecast to track eastward along the front as it gradually shifts southeastward, moving in tandem with a shortwave trough moving through the northern Plains into the Upper Midwest. Buoyancy will be more limited here than areas farther south, but still sufficient for a few stronger, more organized storms, particularly since the deep-layer vertical shear will be stronger. Discrete storms with large hail as the primary risk are possible early in the convective cycle. Thereafter, a trend towards more bowing segments with damaging gusts is expected. Multiple rounds of storms are possible, and the overall coverage is expected to be high enough to merit introducing 15% hail and wind probabilities. ...Lower MI... An MCV (associated with an overnight MCS) is moving across northern IL/far southern WI this morning. Activity associated with this MCV is currently weak and non-severe, but potential for re-intensification exists this afternoon as activity moves into northern IN and southern lower MI. Cloud cover introduces some uncertainty regarding daytime heating and resultant buoyancy. However, if sufficient daytime heating can occur, steep lapse rates and mesoscale organization of the MCS could result in sporadic damaging winds. ..Mosier/Chalmers.. 06/05/2026
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CDT Fri Jun 05 2026 Valid 051630Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FROM NEBRASKA/KANSAS INTO NORTHERN ILLINOIS...AND FROM CENTRAL MINNESOTA INTO CENTRAL WISCONSIN... ...SUMMARY... Thunderstorms with large hail and severe wind gusts are expected to develop late this afternoon and evening from parts of the central Plains into the mid Missouri and mid Mississippi Valleys. Strong to severe wind gusts and hail will also be possible in parts of the upper Mississippi Valley. ...Central Plains into the Mid MS Valley... Morning surface analysis places a low over northwest KS, near the intersection of weak lee troughing and the western edge of a remnant outflow boundary extending across southern NE. Upper 60s/low 70s dewpoints are already in place east/southeast of this surface low and outflow boundary. Southerly/southeasterly flow will persist throughout the day, maintaining a large fetch of low-level moisture advection from the southern Plains into the Mid MS Valley. Steeper mid-level lapse rates are also emerging out of the central High Plains, spreading gradually eastward over these moist low-levels throughout the day. As a result, a corridor of strong to very strong buoyancy is anticipated from south-central NE/north-central KS along the IA/MO border into far west-central IL by the late afternoon. Expectation is that the outflow boundary will gradually retreat northward while the cold front progresses slowly southeastward across SD and NE. Convective initiation is anticipated along both of these boundaries, beginning over north-central KS/south-central NE near the surface low at the outflow boundary/cold front intersection. Most guidance indicates this initiation will occur after 00Z, but earlier initiation appears possible given moist low-levels, robust heating, and mesoscale convergence. Recent RAP soundings indicate minimal convective initiation by 21Z. Once initiation occurs, strong buoyancy (i.e. MLCAPE over 2500 J/kg) will support intense updrafts capable of large to isolated very large hail. Modest deep-layer shear (i.e. effective bulk shear less than 30 kt) could limit storm organization, with a trend towards a more outflow-dominant mode. The generally modest mid-level flow also suggests upscale growth into an organized convective line is low. Even so, a combination of convergence along the outflow and/or cold front, as well as modest warm-air advection, will contribute to additional storm development eastward into the Mid MS Valley. ...Upper Midwest... Recent surface analysis shows a cold front extending from north-central WI southwestward through central SD. A low exists along this boundary near the ND/SD/WI border intersection. This low is forecast to track eastward along the front as it gradually shifts southeastward, moving in tandem with a shortwave trough moving through the northern Plains into the Upper Midwest. Buoyancy will be more limited here than areas farther south, but still sufficient for a few stronger, more organized storms, particularly since the deep-layer vertical shear will be stronger. Discrete storms with large hail as the primary risk are possible early in the convective cycle. Thereafter, a trend towards more bowing segments with damaging gusts is expected. Multiple rounds of storms are possible, and the overall coverage is expected to be high enough to merit introducing 15% hail and wind probabilities. ...Lower MI... An MCV (associated with an overnight MCS) is moving across northern IL/far southern WI this morning. Activity associated with this MCV is currently weak and non-severe, but potential for re-intensification exists this afternoon as activity moves into northern IN and southern lower MI. Cloud cover introduces some uncertainty regarding daytime heating and resultant buoyancy. However, if sufficient daytime heating can occur, steep lapse rates and mesoscale organization of the MCS could result in sporadic damaging winds. ..Mosier/Chalmers.. 06/05/2026
12:32 PMJune 5, 2026
