Subj : DAY2SVR: Marginal Risk To : All From : Mike Powell Date : Sun Jul 30 2023 09:36:00 ACUS02 KWNS 300552 SWODY2 SPC AC 300551 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1251 AM CDT Sun Jul 30 2023 Valid 311200Z - 011200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN HIGH PLAINS...SOUTHERN ARIZONA...AND PORTIONS OF THE GEORGIA AND CAROLINAS COASTAL VICINITY... ....SUMMARY... Isolated strong to severe thunderstorms capable of producing hail and strong gusts are possible on Monday across the northern High Plains. Additional storms producing strong gusts are expected across southern Arizona, and across portions of the Georgia and Carolinas coastal vicinity. ....Synopsis... An upper trough will remain oriented near the Atlantic coast on Monday. Meanwhile, an upper anticyclone will be centered over the southern Plains, with ridging extending into the northern High Plains. Moderate northwesterly mid/upper flow will extend from the northern Plains toward the TN Valley. Surface high pressure will persist over the Midwest with a surface boundary forecast near the central Gulf Coast and extending northeast through southeast GA into the eastern Carolinas and southeast VA. Meanwhile a surface trough will extend southward through the northern into the central High Plains from eastern MT to eastern CO. South/southeasterly low-level flow to the east of this surface trough will maintain a seasonally moist and unstable airmass. Quite a bit of uncertainty regarding severe potential exists within this overall pattern. This is typical for the time of year, as large-scale ascent will remain somewhat modest and severe potential tied to mesoscale features/boundaries that will be influenced by prior day's convection. This may result in some larger-than-typical changes to severe probabilities/areas in subsequent outlooks. ....GA into the Carolinas... A very moist and unstable airmass will reside near a surface boundary during the afternoon. Diurnal thunderstorm activity may pose some risk for locally damaging gusts, given steep low-level lapse rates and PW values near 2 inches. Forecast soundings indicate marginal vertical shear (around 20 kt effective-shear magnitudes), but clustering may increase damaging-gust potential via storm interactions/consolidating outflows before activity diminishes during the early evening. ....Northern High Plains... Forecast guidance indicates a vorticity maximum rotating through the upper ridge from the Four Corners vicinity toward eastern WY. The timing of this feature varies, but this should provide focus for organized thunderstorm development amid moist, southeasterly low-level upslope flow along the surface trough. Widely scattered convection offering hail and strong gust potential is expected during the evening. ....Southern AZ... Monsoonal moisture will remain in place across southern AZ on Monday. Thunderstorms are expected to develop during the afternoon near higher terrain, while mid/upper easterly flow will support clusters developing westward across the lower desert. Strong gusts will accompany this activity during the late afternoon into the evening. ....Mid-MO/MS Valley vicinity... Model guidance varies greatly with regards to potential morning convection continuing from the Day 1/Sunday period. This will influence severe potential during the afternoon/evening within a moist/unstable and moderately sheared environment. Severe probabilities may be needed in subsequent outlooks if confidence increases in evolution/timing of potential thunderstorm activity. ...Leitman.. 07/30/2023 $$ --- SBBSecho 3.14-Linux * Origin: Ilink: CCO - capitolcityonline.net (454:1/105) .