Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Jun 06 2023 06:01:44 ACUS02 KWNS 060601 SWODY2 SPC AC 060600 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue Jun 06 2023 Valid 071200Z - 081200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN HIGH PLAINS...NORTHWEST...NORTHERN PLAINS/UPPER MIDWEST...CAROLINAS VICINITY...AND FLORIDA... ....SUMMARY... Isolated strong to severe thunderstorms appear possible Wednesday across parts of the southern High Plains, Northwest, northern Plains/Upper Midwest, Carolinas vicinity, and Florida. ....Synopsis... Upper ridging will remain centered over the northern/central Plains on Wednesday. An upper low is forecast to persist over the Northeast and Canadian Maritime provinces, with a mid-level shortwave trough expected to move generally southward across the Great Lakes, OH Valley, and Mid-Atlantic through the period. This should encourage mid/upper-level troughing over much of the eastern CONUS. Across the western states, a mid/upper-level low initially over CA should develop very slowly eastward across the Sierras and western Great Basin. A modestly enhanced upper-level sub-tropical jet should extend across northern Mexico into the southern Plains, Gulf of Mexico, and parts of FL. ....Southern High Plains... Scattered thunderstorms are forecast to form over the higher terrain of central/eastern NM and west TX Wednesday afternoon. Although weak upper ridging will persist across this region, modestly enhanced mid/upper-level westerly winds should be present with southward extent across the southern High Plains in association with a sub-tropical jet. Deep-layer shear should generally range around 20-35 kt, perhaps slightly weaker towards CO/KS. Loosely organized thunderstorm clusters spreading eastward Wednesday afternoon/evening may be capable of producing isolated severe gusts as low-level lapse rates steepen through the day. Occasional large hail also appears possible, especially across parts of west TX where marginal supercells may occur with slightly stronger effective bulk shear. ....Northern California into Oregon/Idaho and Western Montana... Similar to Day 1/Tuesday, thunderstorms should initially develop over the higher terrain of northern CA due to orographic influences and weak ascent on the northern periphery of an upper low. With seasonably cool temperatures aloft and modest deep-layer shear forecast, some of these thunderstorms could produce marginally severe hail. Additional convective development should occur farther east into OR/ID and parts of western MT. While low-level moisture is forecast to remain rather limited, sufficient instability to support high-based thunderstorms is still forecast. 20-30 kt of effective bulk shear should also provide modest updraft organization. Isolated severe wind gusts should be the main threat with convective clusters as they spread generally west-northwestward with time. Some hail could also occur with initial development. ....Carolinas and Vicinity... Weak to moderate instability should develop Wednesday afternoon along and south of a weak surface trough/front from central GA across coastal SC/NC. Low-level convergence is forecast to remain weak, as low/mid-level flow should be mostly westerly and parallel to the boundary. Still, strengthening winds with height, especially at mid/upper levels in association with an amplifying upper trough, should support around 25-35 kt of deep-layer shear. Any thunderstorms that can form along the boundary and spread eastward towards the Atlantic Coast could produce isolated damaging winds, and perhaps marginally severe hail, before moving offshore. Overall convective coverage should remain fairly isolated. ....Florida... A weak, low-amplitude shortwave trough embedded within an upper-level sub-tropical jet may advance eastward across the Gulf of Mexico and FL Peninsula on Wednesday. A seasonably moist low-level airmass should be present across this area, and daytime heating should encourage at least moderate instability along the Atlantic Coast by early afternoon. Thunderstorms should preferentially form along the Atlantic Coast sea breeze and perhaps the Everglades, where low-level convergence should be slightly greater. Low-level winds are expected to remain weak, but west-southwesterly flow should strengthen with height at mid/upper levels. Around 25-35 kt of deep-layer shear should promote some updraft organization. Occasional damaging winds and severe hail may occur with the more robust cores before they move offshore. But, poor mid-level lapse rates should tend to limit updraft intensity to some extent, and keep the overall severe threat fairly isolated/marginal. ....Northern Plains/Upper Midwest... On the eastern side of upper ridging, isolated to scattered thunderstorms will probably develop Wednesday afternoon along a nearly stationary surface front. This convection should then spread southward across eastern Dakotas/NE and western MN/IA through early evening. Although flow through mid-levels should remain fairly weak, deep-layer shear peaking around 20-25 kt should aid modest updraft intensity and organization. Loosely organized multicell clusters may produce isolated strong to severe wind gusts, with some potential for a remnant MCV to provide a focus for renewed convective development Wednesday afternoon. Occasional marginally severe hail may occur as well. ...Gleason.. 06/06/2023 $$ = = = To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .