Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jul 23 2023 17:31:05 ACUS02 KWNS 231731 SWODY2 SPC AC 231729 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sun Jul 23 2023 Valid 241200Z - 251200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE MIDWEST...MID/UPPER MS VALLEY...OH VALLEY...AND NORTHEAST... ....SUMMARY... Isolated severe thunderstorms are possible on Monday across parts of the Midwest, mid/upper Mississippi Valley, Ohio Valley, and Northeast. ....Synopsis... An upper ridge will remain anchored over the southern/central Rockies on Monday, as a mid/upper-level cyclone and attendant trough move into the Pacific Northwest, and a broad upper trough remains over much of the eastern CONUS. At the surface, a remnant boundary will be draped from somewhere near the Gulf Coast into the Mid Atlantic. A weak surface low may develop over the central Plains, while another weak surface low/trough will move eastward across the OH Valley vicinity. ....Northeast... A shortwave mid/upper-level trough is forecast to move from the lower Great Lakes toward northern New England on Monday. Modest low-level moisture and diurnal heating will support MLCAPE of 750-1500 by late morning into the afternoon, and scattered thunderstorm development is expected from central PA into parts of NY/VT, immediately in advance of the shortwave. Southwesterly midlevel flow associated with the upper trough will support effective shear generally in the 25-35 kt range, sufficient for a few modestly organized cells/clusters capable of locally damaging wind and possibly some hail. ....OH Valley and vicinity... Most guidance suggests a weak surface low/trough will move slowly eastward across parts of the OH Valley on Monday. This may aid in diurnal thunderstorm development within an environment characterized by moderate to strong buoyancy (MLCAPE 1500-3000 J/kg). Storm coverage and location remain rather uncertain, but effective shear of 20-30 kt within a weak northwesterly flow regime could support a few stronger multicells and clusters capable of producing hail and locally damaging wind. ....Mid/upper MS Valley and Midwest... A low-predictability northwest-flow regime will remain in place from parts of the northern/central Plains into the Midwest and mid/upper MS Valley on Monday. The details of storm development, coverage, and timing remain uncertain, but the environment will be conditionally favorable for supercells and organized clusters wherever notable diurnal destabilization can occur. Morning convection may be ongoing Monday morning across parts of eastern NE/KS into western IA/MS, in association with a southwesterly low-level jet. A localized severe hail/wind threat cannot be ruled out with the stronger morning storms. Outflow and potential MCV development related to morning convection may support redevelopment farther south toward the Ozarks Monday afternoon/evening, with some continued potential for isolated severe hail/wind with the strongest storms. Diurnal development will also be possible farther north into parts of MN/WI, within a weak but persistent low-level warm advection regime. If storms can mature in this area, isolated southeast-moving supercells will be possible. Nocturnal convection may develop late Monday night as the low-level jet increases, potentially posing an isolated severe risk into parts of IA/MO. ....Northern UT into the northern Rockies... High-based convection is expected Monday afternoon/evening in association with a shortwave trough moving around the periphery of the upper ridge. Localized severe gusts will be possible from northern UT into parts of the northern Rockies, though with limited instability, storm intensity and organization remains uncertain at this time. Severe-wind probabilities may eventually be needed if confidence increases in more organized storm development. ...Dean.. 07/23/2023 $$ = = = 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) .