Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
831 ACUS03 KWNS 280730 SWODY3 SPC AC 280729 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Tue May 28 2024 Valid 301200Z - 311200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY AFTERNOON INTO THURSDAY NIGHT ACROSS PARTS OF EASTERN COLORADO...WESTERN KANSAS...WESTERN OKLAHOMA...NORTHWESTERN TEXAS...NORTHEASTERN NEW MEXICO... ...SUMMARY... Severe thunderstorms are possible across parts of the central and southern High Plains Thursday afternoon through Thursday night. This may include a few supercells initially, before one or two thunderstorm clusters develop and organize, posing a risk for severe wind gusts in addition to large hail. ...Synopsis... Large-scale mid-level troughing on the leading edge of stronger westerlies emanating from the northern mid-latitude Pacific may linger across the northern U.S. Rockies and Great Plains through this period. However, it appears that the primary embedded perturbation will be forced to pivot north of the international border through the eastern Canadian Prairies, accompanied by continuing surface cyclogenesis centered over northern Saskatchewan. As this occurs, initially prominent downstream ridging will become suppressed southeastward across the Lake Superior and adjacent northwestern Ontario vicinity, and amplified troughing further downstream may slowly begin to shift across the Atlantic Seaboard. In the southern mid- into subtropical latitudes, broad weak mid-level troughing probably will linger across the northeastern Gulf of Mexico and Florida vicinity, downstream of suppressed subtropical ridging. At least a couple of weak waves are forecast to continue migrating around the periphery of this ridge, including one slowly across and east of the southern Rockies Thursday through Thursday night. Seasonably high boundary-layer moisture content appears likely to remain confined to the southern Great Plains into deepening surface troughing to the lee of the southern Rockies through this period. It appears that warm elevated mixed-layer air will slowly advect to the east of the southern Rockies, and contribute to a strengthening lower/mid-level baroclinic zone roughly from the lee of the Front Range and Sangre de Cristo Mountains into northwestern Texas by late Thursday afternoon. Along and to the southwest of this zone, steep lower/mid-tropospheric lapse rates may contribute to sizable mixed-layer CAPE on the order of 2000-4000 J/kg with daytime heating. ...Central/Southern High Plains... Early period warm advection driven convection preceding the eastward advection of the elevated mixed-layer air could be a complicating factor with regard to destabilization and subsequent convective development through Thursday and Thursday night. However, the strengthening baroclinic zone may become the focus for organizing upscale growing convection, initially forming within the lee surface troughing and/or propagating off the higher terrain to the west. Given the potential instability, this could include the evolution of one or two prominent mesoscale convective vortices with strengthening mid-level rear inflow contributing to potential for sustained strong to severe surface gusts as the storms clusters and associated surface cold pools tend to propagate southeastward along the baroclinic zone. It is possible that this may become particularly focused across the Texas Panhandle into northwest Texas by late Thursday evening, aided by forcing associated with the short wave impulse emerging from the Southwest. Severe wind probabilities might need to be increased across this region in later outlooks for this period. ..Kerr.. 05/28/2024 $$