Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Apr 01 2023 04:39:34 ACUS02 KWNS 010439 SWODY2 SPC AC 010437 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1137 PM CDT Fri Mar 31 2023 Valid 021200Z - 031200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SUNDAY THROUGH SUNDAY EVENING ACROSS PARTS OF CENTRAL AND NORTHERN TEXAS INTO SOUTHERN OKLAHOMA...SOUTHWESTERN ARKANSAS AND NORTHWESTERN LOUISIANA... ....SUMMARY... A few strong storms may impact parts of the southern Great Plains into the Ark-La-Tex vicinity Sunday into Sunday evening, perhaps accompanied by at least some risk for severe weather. ....Synopsis... Models continue to indicate substantial amplification of large-scale mid-level ridging within the westerlies across the northeastern mid-latitude Pacific into and through this period. Downstream of this regime, a significant mid-level trough is forecast to dig more substantively, from near the Pacific Northwest coast through the Sierra Nevada vicinity by 12Z Monday, while large-scale mid-level ridging builds east of the southern Rockies toward the Mississippi Valley. At the same time, mid-level subtropical ridging centered near the Yucatan Peninsula will remain prominent, while a mid-level low of Arctic origins lingers across southern Hudson Bay. A deep-layer cyclone evolving to the southeast and east-southeast of this latter feature is forecast to slowly migrate across the Canadian Maritimes, while renewed cyclogenesis takes place offshore over the northwestern Atlantic. A cold front trailing the cyclone is forecast to generally stall and weaken across the eastern Gulf coast into lower Mississippi Valley vicinity, while redeveloping northward as a warm front, through parts of the southern Great Plains, in response to deepening surface troughing to the lee of the southern Rockies. Modest strengthening of southerly low-level flow across the lower Rio Grande through the southeastern Great Plains and lower Mississippi Valley likely will be accompanied by moisture return. This will contribute to increasing potential instability beneath steepening lapse rates associated with northeastward and eastward advecting elevated mixed-layer air. ....Southern Great Plains into Ark-La-Tex... Appreciable spread remains evident within the model output concerning a relatively modest/low-amplitude perturbation likely to be progressing east-northeast of the southern Rockies by early Sunday, in advance of the more prominent digging Pacific coast troughing. It appears that lower/mid-tropospheric warm advection preceding the lead perturbation may support increasing thunderstorm development during the morning through midday across parts of northwest Texas and southwestern Oklahoma, before spreading eastward across the Red River through Ark-La-Tex vicinity during the day. Based on the latest forecast soundings from the Rapid Refresh and NAM, initially elevated moisture return may contribute to thermodynamic profiles with sufficient convective instability and CAPE to support at least some risk for severe hail. This may be aided by strong shear through the convective layer, which could support the evolution of a few supercell structures. As convection becomes increasingly widespread and progresses eastward into the lower Mississippi Valley late Sunday afternoon into Sunday night, this threat is expected to wane. At least somewhat more unclear, mid-level inhibition may remain relatively weak into late afternoon or evening across parts of the Texas Big Country, where boundary-layer destabilization along a developing dryline may support the development of an isolated supercell or two. This activity could pose a short-lived risk for severe hail, locally strong gusts and perhaps a tornado before dissipating Sunday evening. ...Kerr.. 04/01/2023 $$ = = = 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) .