Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0655 AM CST Sun Jan 15 2017 Valid 151300Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS WEST-CENTRAL TO NORTH-CENTRAL TX... ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING THE SLIGHT INTO SOUTHEAST OK... ...SUMMARY... Scattered severe storms will be possible this afternoon into tonight across parts of west-central to north-central Texas. A few tornadoes, damaging winds, and large hail are anticipated. ...Synopsis... Compact shortwave trough along the Sonora/Chihuahua border will eject northeast into OK by early Monday. Attendant surface low should become established over the Permian Basin this afternoon and track northeast into central OK overnight along an advancing warm front. As this occurs, a Pacific cold front will push east into central TX. ...Southern Great Plains... A modifying warm sector across southern TX will attempt to advance north as a swath of 35-50 kt low-level southerlies persist through this afternoon, and further strengthen tonight. Model mean mixing ratios appear too moist compared to 12Z Del Rio and Corpus Christi observed soundings. In addition, a modified continental air mass, reinforced by ongoing and additional elevated convection today, should limit the northwest advancement of the warm sector to parts of west-central and north-central TX. Largest buoyancy with around 1000 J/kg MLCAPE should be confined to the Edwards Plateau where an elevated mixed layer will be most pronounced. Surface-based storms appear most likely to form across the Pecos Valley in the early afternoon as mid-level DCVA/height falls overspread the destabilizing northwest periphery of the modified warm sector. This activity should further expand in coverage and shift east-northeast, with an extensive squall line probable by late evening from parts of south-central OK through central TX. 30-50 kt effective bulk shear will support organized storm structures including supercells and bowing line segments. Along the southern periphery of development over the Edwards Plateau, where convection would seemingly have the best potential to remain discrete, model soundings indicate veer-back-veer vertical wind profiles with a weakness in the hodograph around 700 mb. This may temper a greater tornado risk from being realized. Farther northeast along the Red River, where mode should become increasingly linear with time, the primary uncertainty is how far north surface-based instability and a corresponding damaging wind/brief tornado risk will extend into OK tonight. ..Grams/Smith.. 01/15/2017Read more
from SPC Forecast Products http://ift.tt/rATNzD
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