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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.


Sunday, August 8, 2021

SPC Aug 8, 2021 0600 UTC Day 1 Convective Outlook

SPC 1200Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1251 AM CDT Sun Aug 08 2021 Valid 081200Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE MISSOURI VICINITY NORTH-NORTHEASTWARD INTO WISCONSIN... ...SUMMARY... Scattered strong to severe thunderstorms are possible Sunday from Wisconsin and Iowa southward into the Ozark Plateau. Isolated severe storms are also possible across portions of Montana. ...Synopsis... A mid-level short-wave trough is forecast to make continued eastward progress across the central U.S., as a stronger trough/low advances across the northwestern states and into the northern Intermountain region. In the East, a weak trough will shift across the Mid-Atlantic region through the period. At the surface, a strong cold front will move across the Northwest and northern Intermountain region, in conjunction with the advancing upper system. A much weaker/rather diffuse surface pattern will reside over the central U.S., with convective boundaries likely proving more pronounced than any synoptic-scale features. Weak high pressure will largely prevail over the East. ...Missouri vicinity to Wisconsin... Lingering convection is expected to be ongoing at the start of the period, across parts of the upper Mississippi Valley/Upper Great Lakes, with diminishing convection/remnant outflows crossing the mid Missouri Valley and Kansas/Oklahoma. The ongoing convection, and asssociated convective debris/outflows cast some uncertainty with respect to environmental evolution through the day, but in general, moderate destabilization is expected -- aided by a moist boundary layer. By early afternoon, increasing storm development is expected, within a zone from eastern Kansas/western Missouri north-northeastward into Wisconsin. Given moderate deep-layer flow, local organization of convection will likely result in a few severe storms capable of producing mainly damaging winds, along with some hail. Some upscale growth into a band of storms may occur -- with current indications suggesting a zone from northern Missouri/southeastern Iowa into western Illinois being a more likely location for a more organized convective band by late afternoon. While convection -- and some severe risk -- will likely continue into the evening, a gradual decrease in convective intensity is expected diurnally. ...Montana... A cold front is progged to move across MT today, in conjunction with a progressive upper short-wave trough. Ascent focused along the front will support development of a band of convection, though weak instability will limit overall convective intensity. Still, a few stronger wind gusts may occur, and thus will maintain MRGL/5% wind risk across the region. Given the weak CAPE, the risk should be primarily diurnal, diminishing after sunset with the onset of low-level stabilization. ..Goss/Lyons.. 08/08/2021 Read more LIVE:
SUNRISE AND SUNSET TIMES IN UTC (if you're not logged in to Google)
CHICAGO UTC-6 during CST (Central Standard Time, e.g., winter)
CHICAGO UTC-5 during CDT (Daylight Savings Time, e.g., summer)