Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue May 09 2023 12:51:30 ACUS01 KWNS 091251 SWODY1 SPC AC 091249 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 AM CDT Tue May 09 2023 Valid 091300Z - 101200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS NORTH-CENTRAL TO SOUTHEAST KS... ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SOUTHEAST VA AND EASTERN NC... ....SUMMARY... A corridor of severe thunderstorms is expected today across parts of Kansas, with embedded swaths capable of producing very large hail, damaging severe gusts, and a few brief tornadoes. Scattered damaging winds and isolated severe hail is also possible this afternoon into early evening across eastern North Carolina and southeast Virginia. ....KS vicinity... While a broad low-amplitude mid/upper ridge will prevail over the central to northern Great Plains today, persistent low-level warm theta-e advection has supported increasing elevated convection this morning, focused on the northwest KS/southwest NE border area. With pronounced differential boundary-layer heating expected owing to nearly full insolation south of the elevated convective corridor, strengthening frontogenesis is expected across northern KS. With strong effective bulk shear already present, sustained and potentially long-track supercell development is expected to persist into the afternoon. This should yield a relatively confined swath of severe events, initially in the form of large hail and then transitioning into a hail/wind threat as convection becomes surface-based by early afternoon. This activity should evolve into a southeast-progressing supercell cluster/small MCS during the afternoon, with an increasing wind/brief tornado threat as it matures. Additional development may occur towards late afternoon, trailing westward to the dryline in southwest KS. Should this occur, a broader MCS may form and push south-southeast into the Ozark Plateau to northern OK this evening. But an increasingly disorganized trend is anticipated tonight as mid-level flow weakens substantially with southern extent owing to the presence of an anticyclone over southern OK. ....Southeast VA and eastern Carolinas... A shortwave trough will move southeast from the Lower Great Lakes across the Mid-Atlantic States today. A belt of enhanced westerly flow will accompany this feature, and provide support for sufficient deep-layer shear to foster thunderstorm organization. Although surface winds will be veered mostly to the west-northwest, there should still be adequate low-level moisture in place for weak to moderate buoyancy to develop given abundant insolation. Most guidance shows isolated to scattered thunderstorms developing this afternoon with a mix of multicells and a few supercells. A threat for both severe hail and damaging winds should be greatest across southeast VA and northeast NC, with more of an isolated damaging wind threat into SC. ....TX/LA Coastal Plain... A pair of slow-moving MCSs embedded within a broader weakly sheared environment are ongoing across south TX and the northwest Gulf. Scattered to numerous thunderstorms will likely increase downstream of these features, later this morning into the afternoon. Despite the weak shear, low to mid 70s surface dew points suggest a threat for wet microbursts and isolated severe hail will be possible. A conditionally favorable supercell threat may redevelop in a portion of Deep South TX later this afternoon. A belt of enhanced mid-level westerlies to the south of the minor mid-level lows will yield adequate bulk shear for supercells along residual convective outflow. Primary uncertainty is the degree of low-level moisture recovery in the wake of morning convective outflows (mean mixing ratio below 12 g/kg in the 12Z BRO sounding). ....Northeast CO to western ND... Isolated to scattered late-afternoon thunderstorm development is possible along a surface trough from the NE Panhandle to western ND vicinity. While MLCAPE will likely remain weak (at or below 1000 J/kg), 500-mb southwesterlies around 30-35 kt will support a threat for isolated severe hail and locally strong gusts into the early evening. Overnight, a cluster of elevated thunderstorms should develop in the northeast CO to WY/NE border area as weak mid-level height falls overspread weak low-level upslope flow. Isolated large hail will be the main threat. ...Grams/Broyles.. 05/09/2023 $$ = = = 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) .