Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
198 ACUS48 KWNS 120847 SWOD48 SPC AC 120845 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CDT Sun May 12 2024 Valid 151200Z - 201200Z ...DISCUSSION... Medium-range guidance is in relatively good agreement that a southern-stream shortwave trough will progress across the Baja Peninsula and much of northern Mexico on D4/Wednesday, continuing eastward across the southern High Plains and much of TX on D5/Thursday, and the Lower MS and TN Valleys, and much of the Southeast on D6/Friday. Some severe thunderstorms appear possible during each day of this sequence, beginning with the southern High Plains on D4/Wednesday. Modest low-level moisture advection is anticipated across the southern Plains, which will support airmass destabilization amid strong heating. Large-scale ascent will be nebulous, and convective initiation will likely result from low-level convergence. Uncertainty regarding destabilization, limited coverage and low predictability preclude delineation any areas with this outlook on D4/Wednesday. Greater thunderstorm coverage is anticipated across the southern Plains (particularly TX) on D5/Thursday, as the aforementioned shortwave trough begins interacting with the moistening airmass over the region. Both vertical shear and buoyancy are expected to be sufficient for severe thunderstorms. However, uncertainty regarding the evolution of preceding night`s thunderstorms, as well as character and location of the warm sector, results in limited forecast confidence. Similar issues plague D6/Friday downstream from east/southeast TX across the Southeast, with even more uncertainty on how preceding precipitation evolves and its effect on the warm sector. After D6/Friday, guidance shows increasing variance, resulting in limited predictability. ..Mosier.. 05/12/2024