SPC AC 150544 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1144 PM CST Sat Dec 14 2024 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN FAR NORTH TX TO NORTHWEST AR... ...SUMMARY... A low-end severe threat, primarily in the form of marginal hail, is possible tonight across a portion of the Red River Valley into the southern Ozark Plateau. ...Synopsis... A shortwave trough will progress from the northern Great Basin into the Upper Midwest by tonight, with low-amplitude impulses moving east across the Southwest. Primary surface cyclone will deepen as it tracks from the Black Hills to the Lake of the Woods vicinity. An occluded/cold front will arc south into the Ozarks by tonight, with trailing portion extending southwestward in OK/TX. ...North TX to the Lower OH Valley... A broad, low-level warm/moist conveyor will become established from the Lower Rio Grande Valley northeastward into the Lower OH Valley through tonight. Low-amplitude shortwave ridging should preclude appreciable thunderstorm development until late evening. A swath of elevated storms is expected to blossom into the overnight, from parts of eastern OK into the Lower OH Valley as weak mid-level height falls overspread the gradually moistening corridor. The southwest extent of this regime into far north TX should contain surface-based parcels, although low-level lapse rates may be poor. Nearly unidirectional southwesterly wind profiles are progged across much of the warm conveyor, ahead of the similarly oriented cold front. M-shaped type hodographs are anticipated from southeast OK southwestward, with weakness in the flow around 700 mb, where MUCAPE appears largest from 1000-2000 J/kg. Non-FV3 members of the 00Z HREF and available NSSL-MPAS runs indicate minimal 2-5 km UH signal. Given these factors, storm mode will probably become messy early in the convective development life cycle. Still, conditional potential exists, amid an adequate combo of effective bulk shear and MUCAPE, for a few deeper updrafts to acquire transient rotation, with an associated marginally severe hail threat. Where exactly that transitions to purely small hail magnitudes is uncertain with northeast extent, as mid-level lapse rates should be more muted and buoyancy will be less. ..Grams/Lyons.. 12/15/2024 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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2024-12-15 05:48:22