Subj : DAY2SVR: Marginal Risk To : All From : Mike Powell Date : Sat Aug 19 2023 07:33:00 ACUS02 KWNS 190452 SWODY2 SPC AC 190450 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1150 PM CDT Fri Aug 18 2023 Valid 201200Z - 211200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SUNDAY INTO SUNDAY NIGHT ACROSS PARTS OF SOUTHEASTERN CALIFORNIA...WESTERN INTO CENTRAL ARIZONA AND SOUTHERN NEVADA... ....SUMMARY... Showers and thunderstorms accompanying the weakening tropical cyclone Hilary may become capable of producing a few severe wind gust and perhaps a tornado or two across parts of the lower Colorado Valley into the Mohave Desert Sunday afternoon into Sunday night. ....Synopsis... A prominent mid-level ridge will continue to encompass much of the U.S. from the Rockies into the middle and south Atlantic Seaboard through this period, with the center of highest heights building further across the central Great Plains/lower Missouri Valley vicinity. As mid-level troughing digs toward the Pacific Northwest, broad downstream short wave ridging may also build north of the international border through much of the southern interior Canadian provinces. Within weak mid-level troughing extending southward along the Pacific coast, to the south of the split stronger westerlies, a weak mid-level low is forecast to linger to the southwest of San Francisco Bay. Within a broadly confluent, southerly regime to its east, the weakening tropical cyclone Hilary may become increasingly sheared while accelerating north of the Southwestern international border late Sunday through Sunday night. ....Southwest... To the north and northeast of Hilary, it still appears that 50-70 kt flow in the 850-700 mb layer will spread northward across the lower Colorado Valley into Mohave Desert Sunday afternoon and evening. Near and just west of the Colorado River, forecast soundings indicate saturating boundary-layer profiles with lower and perhaps mid 70s F surface dew points, coincident with enlarging clockwise-curved low-level hodographs. If this occurs, it appears that the environment could become conducive to the evolution of a few supercell structures capable of producing tornadoes. Otherwise, particularly in surrounding portions of the Southwest, where warmer/drier mixed boundary-layers may evolve, downward mixing of the higher momentum air in scattered stronger convection may contribute to a few severe surface gusts. ...Kerr.. 08/19/2023 $$ --- SBBSecho 3.14-Linux * Origin: Ilink: CCO - capitolcityonline.net (454:1/105) .