SPC Oct 11, 2017 Day 4-8 Severe Weather Outlook

By Newsroom America Feeds at 11 Oct 2017

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0152 AM CDT Wed Oct 11 2017 Valid 141200Z - 191200Z ...DISCUSSION... ...Saturday/Day 4 and Sunday/Day 5... The medium range models including the ECWMF, GFS, Canadian and UKmet move an upper-level trough across the Rockies and into the Great Plains Saturday and Saturday night. Ahead of the system, a low-level jet is forecast to strengthen from the southern Plains northeastward into the western Great Lakes. Scattered to numerous thunderstorms are forecast to develop along the western edge of the low-level jet Saturday evening persisting through the overnight period. The combination of instability and deep-layer shear along this corridor appear sufficient for a severe threat with isolated large hail and wind damage possible. On Sunday, the upper-level trough is forecast to move eastward into the lower Missouri and mid to upper Mississippi Valleys. At the surface, a cold front is forecast to advance southeastward into the Ohio and mid Mississippi Valleys. Thunderstorm development will be possible along the front Sunday afternoon. A marginal severe threat may develop along the front from the Ohio Valley northeastward into the lower Great Lakes where strong deep-layer shear is forecast but instability should remain very weak. ...Monday/Day 6 to Wednesday/Day 8... On Monday, the models are decent agreement, moving an upper-level trough into the Ohio and Tennessee Valleys and developing northwest mid-level flow across the central U.S. At the surface, a cold front is forecast to move into the Southeast. Thunderstorms will be possible along the front Monday afternoon. On Tuesday and Wednesday, surface high pressure becomes dominant in the eastern half of the U.S. A moist airmass is forecast to remain over the Florida Peninsula where thunderstorm development will be possible each afternoon. Read more



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