Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0341 AM CST Wed Jan 27 2021 Valid 301200Z - 041200Z ...DISCUSSION... Medium-range models continue to exhibit reasonable large-scale agreement with respect to evolution of the upper pattern, through roughly Day 7. Beyond that, differences quickly arise with handling of a large trough crossing the West late in the period. Prior to then, the pattern aloft will be characterized by the progression of a trough -- initially situated over the southern Rockies/central and southern High Plains. As this feature evolves/shifts eastward with time, it will be accompanied by a well-developed surface low/frontal system, that models suggest will move from the High Plains early Day 4 (Saturday), to near/off the East Coast by the end of Day 6 (Tuesday morning). Despite the well-developed nature of this surface system, its warm sector will likely remain notably lacking in instability, due to the antecedent cP airmass intrusion through the Gulf of Mexico, and persistence of ridging aloft across the western Atlantic and into the Gulf. As such, though precipitation -- including weak/low-topped convection -- will accompany passage of the system, severe weather is not expected.
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