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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.

Thursday, June 8, 2023

SPC Jun 8, 2023 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0106 AM CDT Thu Jun 08 2023 Valid 081200Z - 091200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF TEXAS...THE SOUTHEAST...THE NORTHERN PLAINS...AND THE MONTANA VICINITY... ...SUMMARY... Isolated strong to severe thunderstorms are expected today across parts of Texas, the Southeast, Dakotas, and northern Rockies/High Plains. Isolated damaging winds and hail should be the main threats. ...Synopsis... A large area of cyclonic flow is progged over the eastern U.S. today, surrounding a low over New England. Meanwhile, a weaker low will shift northward across the Great Basin. In between, ridging will prevail across the central U.S. through Friday morning. At the surface, a baroclinic zone will extend from southern New England across the Gulf Stream and then back onshore across the Southeast this afternoon. From there, the front will arc northwestward across the Plains, to eastern Montana. Elsewhere, high pressure will prevail. ...Texas... Questions with respect to ongoing, early-period convection and associated cloud cover remain evident, which complicates the forecast across Texas. From a larger-scale perspective, afternoon heating in areas uncontaminated by ongoing clouds/convection will result in moderate destabilization, leading to reintensification/redevelopment of storms. With enhanced northwesterly flow aloft prevailing across central and southern Texas, atop low-level southerlies, shear will be sufficient to support organized storms. However, the aforementioned uncertainties result in questions regarding both location -- and number -- of stronger storms, and this is borne out by the latest solutions from the various CAM runs. The HRRR in particular would support a potential upgrade to slight risk, depicting an MCS developing across central Texas and then propagating/expanding southeastward across the Texas Coastal Plain with time. However, other CAMs are much less bullish with respect to convective coverage/organization. As such, will hold off on any upgrade at this time, and maintain broad/low probability risk area for hail/wind. ...The Southeast... Isolated thunderstorm development is forecast to begin early this afternoon, from southern South Carolina into southern Georgia, as a moist boundary layer ahead of a weak cold front advancing very slowly southeastward across the region destabilizes. While the stronger westerlies aloft will remain to the cool side of the boundary, ample shear is expected along and just ahead of the boundary, which will likely support a few sustained/organized updrafts. While much of the stronger convection may remain just offshore, a few storms capable of producing gusty winds and/or hail near severe levels are expected. Risk may linger through sunset, until storms diminish diurnally and/or shift offshore. ...Northern Plains... A series of very weak mid-level cyclonic disturbances will continue shifting southward across the north-central U.S., within cyclonic flow on the back side of the New England upper low. As a moist airmass just to the eastern/cool side of a quasi-stationary surface front extending northwest to southeast from eastern Montana to Nebraska heats/destabilizes, widely scattered thunderstorm development is expected. While flow aloft is forecast to remain rather weak, some upscale growth of convection into one or two southeastward-moving clusters may occur. A few of the strongest convective elements may prove capable of producing hail/wind gusts in excess of severe levels, before storms diminish diurnally. ...Montana vicinity... As a series of weak cyclonic disturbances aloft shift northward across the northern Rockies/northern High Plains, scattered afternoon thunderstorms are forecast to develop, as daytime heating/destabilization maximize. While flow aloft will remain relatively weak/easterly, ample CAPE atop a moderately deep mixed layer during peak heating suggest potential for a few stronger storms -- capable of gusty/potentially damaging winds, and severe-caliber hail. Risk may continue locally through the evening hours, as large-scale ascent persists across the region. ..Goss/Squitieri.. 06/08/2023 Read more CHECK UPDATE ZOOM GRAPHIC