Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0307 AM CST Sun Dec 13 2020 Valid 161200Z - 211200Z ...DISCUSSION... A significant, remnant short wave perturbation, accelerating out of the southern Great Plains by Tuesday, may reach the southern Mid Atlantic coast by Wednesday evening. As it approaches the coast, medium-range models indicate that it will support substantive further deepening of a frontal wave initially developing off the South Carolina coast by daybreak Wednesday. It might not be entirely out of the question that a moistening and destabilizing warm sector boundary layer could spread across parts of the North Carolina Outer and Inner Banks vicinity Wednesday afternoon or evening. However, at this point, this seems a low probability, and it is not clear that this would support more than a low severe thunderstorm risk. Otherwise, mid/upper flow is forecast to become more zonal across Canada later this week through next weekend, with much of the U.S. remaining under the influence of branching westerlies emanating from the mid-latitude Pacific. It appears that this may include a number of relatively fast moving short wave perturbations. While the potential for significant surface cyclogenesis appears low, even if one of these is able to support at least modest cyclogenesis near Gulf coastal areas, it is not clear that the Gulf boundary layer will be able to modify sufficiently to support a substantive inland return flow of moisture.
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