Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue May 09 2023 19:53:01 ACUS01 KWNS 091952 SWODY1 SPC AC 091951 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0251 PM CDT Tue May 09 2023 Valid 092000Z - 101200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF EASTERN KANSAS INTO FAR WEST-CENTRAL MISSOURI... ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS VICINITY AND SOUTHEAST VIRGINIA INTO EASTERN NORTH CAROLINA... ....SUMMARY... A corridor of severe thunderstorms will continue moving east/southeast across parts of eastern Kansas through evening. Embedded swaths of very large hail, damaging severe gusts, and a few brief tornadoes are possible. Scattered damaging winds and isolated severe hail are also possible through early evening across eastern North Carolina and southeast Virginia. ....20z Update - KS/MO Vicinity... The main changes to the outlook at 20z are to reorient the Enhanced risk (Level 3 of 5) to include more of eastern KS to the west-central MO border. This is based on the expected continued east/southeast motion of the bowing line of convection currently over central to northeast KS. Swaths of damaging gusts, very large hail and a couple of tornadoes will remain possible into early evening. Additional thunderstorm development remains possible with westward extent into parts of western KS along the outflow boundary as low-level upslope flow and strong heating allow for some airmass recovery from morning convection. ....Elsewhere... No other changes have been made to the previous outlook. For details, see previous discussion below. ...Leitman.. 05/09/2023 ..PREV DISCUSSION... /ISSUED 1143 AM CDT Tue May 09 2023/ ....Kansas/southern Nebraska... A severe MCS continues to mature/expand and show early signs of modest southeastward acceleration as of late morning/1130AM CDT across north-central Kansas. As a surface cold pool expands, persistent warm/moist advection will help to maintain this MCS southeastward parallel to the instability/thickness gradient, with additional southward expansion likely across central Kansas early this afternoon as the boundary layer warms/destabilizes. The potential for widespread/locally intense wind gusts will likely increase as the MCS reaches east-central Kansas including the I-135 and near/south of I-70 corridors and Kansas Turnpike vicinity. Large hail will be possible, especially with semi-discrete storms on the southwest flank of the MCS (or completely distinct from it). A brief tornado risk may also exist with line-embedded circulations. Additional strong/severe development cannot be ruled out later this afternoon in vicinity of trailing outflow across northwest Kansas and/or atop the surface cold pool across northern Kansas/far southwest Nebraska. Storms may also develop around late afternoon trailing westward to the dryline in southwest Kansas. Should this occur, a broader MCS may form and push south-southeast into the Ozark Plateau to northern Oklahoma 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 Oklahoma. ....Southeast Virginia and eastern Carolinas... No changes in outlook reasoning/assessment for this region. 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 will 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 Virginia and northeast North Carolina, with more of an isolated damaging wind threat southward into South Carolina. ....Texas/Louisiana... Strong/locally severe thunderstorms are possible this afternoon, influenced by development/intensification on the periphery of multiple MCVs via two de-intensified MCSs. 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 Texas 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 Colorado to western North Dakota... Isolated to scattered late-afternoon thunderstorm development is possible along a surface trough from the Nebraska Panhandle to western North Dakota 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 Colorado to Wyoming/Nebraska border area as weak mid-level height falls overspread weak low-level upslope flow. Isolated large hail will be the main threat. ....Central/eastern Montana... Long hodographs/forcing for ascent enhanced by an approaching mid-level trough, in conjunction with a modestly moist/unstable environment, may allow for some stronger or locally severe storms capable of hail and/or wind from mid-afternoon through early evening. $$ = = = 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) .