Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0317 AM CST Fri Dec 04 2020 Valid 071200Z - 121200Z ...DISCUSSION... Severe potential appears low during the Day 4-8 period. A mean trough will persist across the eastern U.S. through Day 5/Tue. During this time, an upper ridge will spread eastward from portions of the western U.S. to the Plains. Meanwhile, a mid/upper low over CA will become cut-off and migrate southwest over the Pacific offshore from southern CA/northern Baja through Day 6/Wed. By Day 7/Thu, medium range guidance develops the CA/Baja upper low eastward across northern Mexico/southern AZ/NM, with an open wave upper trough ejecting into the southern Plains on Day 8/Fri. Overall, surface high pressure across much of the CONUS and dearth of boundary layer moisture will preclude severe thunderstorm potential through at least Day 6/Wed. Thunderstorm activity may increase late in the period as southwesterly deep layer flow increases ahead of the southwestern U.S./northern Mexico upper low/trough. However, severe storms appear unlikely at this time given poor northward return of Gulf moisture in advance of this system, likely leading to poor thermodynamics.
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