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Archives for the SPC Convective Outlook are updated daily (approximately) with a live map at the beginning of each article. Follow the link at the end of the article to check for current updates on the NOAA/NWS Storm Prediction Center website. Also, see Archives for Chicago's hourly weather data on CARDINAL NEWS Magazine.

Friday, June 11, 2021

SPC Jun 11, 2021 1300 UTC Day 1 Convective Outlook

SPC 1300Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0726 AM CDT Fri Jun 11 2021 Valid 111300Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR EASTERN KS... ...SUMMARY... Severe thunderstorms with damaging winds and large hail are expected today into early tonight from eastern Nebraska southward across eastern Kansas/western Missouri into northern Oklahoma. ...Eastern NE/KS to western MO and northern OK through tonight... A midlevel shortwave trough over the Dakotas this morning will continue northeastward over southern SK/MB through the afternoon, while an associated surface cold front moves southeastward across the central Plains. Widespread convection overnight has generated an extensive cold pool that will act as the effective cold front today from NE into IA/MN. The strongest storms are expected along the southern portion of the remnant overnight storms into NE, and this convection will tend to develop southward through the day into eastern KS and adjacent western MO, around the eastern periphery of a midlevel ridge over the southern High Plains. Though vertical shear will remain rather modest, there could be some mesoscale enhancement due to MCV formation within the persistent NE convection as it develops south-southeastward through the day. Large buoyancy (MLCAPE at or above 4000 J/kg) is expected in advance of the convective cluster, owing daytime heating of a very moist boundary layer (low-mid 70s dewpoints), beneath steep midlevel lapse rates. These thermodynamic profiles will favor strong updrafts capable of supporting large hail, but the primary threat should become damaging winds with a series of downbursts given heavy precipitation loading and large DCAPE near 1500 J/kg. The cluster is expected to move across eastern KS during peak heating with the largest buoyancy and steepest low-level lapse rates, when the damaging-wind threat should be greatest. Some severe threat will likely persist into tonight across at least northern OK, where lift along the front/outflow and residual large CAPE should support additional storm development to the south and southwest. ...Central/northern WI this afternoon/evening... Outflow with weakening pre-frontal convection is moving eastward across MN this morning, and could reach western WI before becoming diffuse this afternoon. A separate/weak baroclinic zone (oriented more northwest-southeast) will also persist through the day. These boundaries could help focus thunderstorm development this afternoon, as well as the cold front approaching from the west (if the outflow becomes diffuse while still in MN). Despite weak vertical shear, moderately large buoyancy (MLCAPE near 2000 J/kg) and DCAPE near 1200 J/kg will favor storms with isolated damaging downbursts and marginally severe hail this afternoon/evening. ..Thompson/Leitman.. 06/11/2021 Read more LIVE: