Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jun 19 2023 06:02:26 ACUS01 KWNS 190602 SWODY1 SPC AC 190600 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Mon Jun 19 2023 Valid 191200Z - 201200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDDLE GULF COAST/SOUTHEAST STATES... ....SUMMARY... Severe thunderstorms capable of producing damaging winds are possible across parts of the middle Gulf Coast states and Southeast today. Additional isolated strong to severe thunderstorms are also possible into parts of the Carolinas, central/north Texas, and the northern Plains. ....Middle Gulf Coast/Southeast States... Clusters of strong/potentially severe storms are likely to be ongoing this morning from southern Mississippi into southern Alabama/southern Georgia and north Florida. A diurnal reintensification of these storms should occur today on the southern fringes of the lingering early day storms/cloud cover. Severe/damaging gusts will be the main hazard associated with this activity given its mainly linear/cluster nature as low-level lapse rates steepen. Other storms should develop later in the afternoon along the westward-extending portion of the front near the middle Gulf Coast, with these storms capable of large hail and damaging winds. This is attributable to ample instability coincident with a belt of moderately strong northwesterly winds aloft. As waves of large-scale ascent pivot around the upper low, additional bands of thunderstorms are expected further north and east across eastern Tennessee into the Carolinas. Instability will be weaker with northward extent. However, steepening low-level lapse rates and a high PW environment may support sporadic strong/damaging wind gusts. Additional clusters of strong storms may develop along sea-breeze boundaries across the Florida Peninsula. Water-loaded downdrafts may pose a risk for strong gusts here as well, along with occasional hail. ....Central/North Texas... Steady height rises are expected as the upper ridge builds over the Plains through tonight, with a related warming of mid-level temperatures and uncertainty regarding the likelihood/extent of late-day deep convective potential. Regardless, a thermally aided surface low should deepen across the Low Rolling Plains, with robust post-dryline mixing (surface temperatures 100+ F) and at least modest near-dryline/triple point convergence suggesting some potential for isolated semi-sustained convection late this afternoon. Any convection that develops and can sustain will have the potential to become a supercell in the presence of seasonally strong (40-55 kt) mid/upper-level northwest flow. Given the presence of steep mid-level lapse rates and moderate to strong instability, isolated large hail may occur with any supercell. Severe-caliber wind gusts are also plausible, as the boundary layer should be very well mixed, with steepened low-level lapse rates due to the robust diurnal heating. Any severe risk should diminish by around, or shortly after, sunset as the boundary layer slowly cools. ....ArkLaTex/Louisiana... On the edge of strong capping aloft, storms are expected to develop tonight near the front across the region, with some potential that these storms will be strong to severe. Very steep mid-level lapse rates and ample elevated buoyancy in the presence of strong shear through the cloud-bearing layer could support some storms capable of large hail. ....Eastern Montana and western/northern North Dakota... The region will be influenced by the eastern periphery of a prominent upper trough centered over the Pacific Northwest and its preceding polar jet. This jet will interface with modest low-level moisture on the cool side of a roughly southwest/northeast-oriented front across the region, where forcing for ascent will be maximized. Widely scattered storms are expected to initially develop this afternoon across southeast Montana and northeast Wyoming near the Bighorn Mountains. This convection should persist/expand northeastward across eastern Montana and parts of western/north North Dakota through evening. Even while overall buoyancy will be modest, deep-layer shear should be strong enough to support some supercells and sustained multicells with an attendant threat for large hail and severe-caliber wind gusts. ...Guyer/Flournoy.. 06/19/2023 $$ = = = 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) .