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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, June 18, 2023

SPC Jun 18, 2023 0600 UTC Day 2 Convective Outlook

LIVE MAP (ABOVE) ... SPC 0600Z Day 2 Outlook Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Sun Jun 18 2023 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL GULF COAST INTO SOUTHWEST GEORGIA... ...SUMMARY... Severe thunderstorms, capable mainly of damaging gusts, are possible across the central Gulf Coast into southwest Georgia on Monday. Additional isolated strong to severe thunderstorms also are possible across much of the rest of Georgia into eastern Tennessee and parts of the Carolinas, and over central Texas. ...Central Gulf Coast into the Carolinas... An upper low and attendant trough will persist over the Ohio Valley to the Gulf Coast on Monday. Deep-layer flow will be somewhat weaker across the Gulf Coast states compared to the past week or so, but 40 kt of west/southwest flow between 700-500 mb atop light southerly low-level will support modest vertical shear to around 25-30 kt. A weak surface low located over western/central KY will not move much through the period, though as attendant surface boundary will sag southward across parts of the lower MS Valley and central MS/AL. Ahead of this boundary, dewpoints in the 70s will be common, aiding in a swath of moderate to strong destabilization across region. A cluster of strong to severe thunderstorms may be ongoing Monday morning across pars of central AL into west-central GA. This activity will spread southeast into a strongly unstable airmass, and may increase in intensity as the boundary layer destabilizes with daytime heating. Severe/damaging gusts will be the main hazard associated with this activity, and a Slight risk (level 2 of 5) has been introduced. There is some uncertainty regarding westward extent of severe potential. Some guidance suggests convection may build westward along the weak surface boundary. However, capping also will be stronger to the west and large-scale ascent weaker. Depending on trends, some modification to the western extent of the Slight risk may be needed in subsequent outlooks. As waves of large-scale ascent pivot around the upper low, additional bands of thunderstorms are expected further north and east across eastern TN into the Carolinas. Instability will be weaker with northward extent further from steeper midlevel lapse rates. However, stronger ascent, steep low-level lapse rates, and high PWs may support sporadic strong gusts. Additional clusters of strong storms may develop along sea-breeze boundaries across the FL Peninsula. Water-loaded downdrafts may pose a risk for strong gusts here as well. ...Central TX... A somewhat conditional risk of isolated severe storms is anticipated late Monday afternoon/early evening. A very moist airmass will reside to the east of a dryline, and beneath very steep midlevel lapse rates. Increasing northwesterly deep-layer flow will produce effective shear magnitudes greater than 40 kt with forecast soundings depicting elongated hodographs. Temperatures are expected to be hot, near/above 100 degrees along the dryline. Accounting for entrainment/dry midlevels, a strongly unstable airmass will still reside over the area. If a cell or two can develop and become sustained, strong/severe outflow winds and large hail would be possible. ..Leitman.. 06/18/2023 Read more CHECK UPDATE ZOOM GRAPHIC