SPC Mar 7, 2018 0700 UTC Day 2 Convective Outlook

By Newsroom America Feeds at 7 Mar 2018

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1145 PM CST Tue Mar 06 2018 Valid 081200Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe storms appears negligible across the U.S. Thursday through Thursday night. ...Discussion... To the southwest of a persistent blocking ridge (centered in the vicinity of Newfoundland and Labrador), models indicate the continued evolution of a broad and deep mid-level closed low to the east of the lower Great Lakes region during this period. As this occurs, amplified cyclonic flow will be maintained east of the Mississippi Valley through the western Atlantic. An associated surface frontal zone may continue to advance southward through the Bahamas and Caribbean, but, after stalling across parts of the southwestern Gulf of Mexico, it probably will begin to retreat northeastward. Upstream, broad mid/upper ridging is expected to prevail across much of the West, into the Plains. However, within one branch of mid-latitude westerlies emanating from the Pacific, it does appear that the increasingly sheared/deformed remnants of a cyclonic circulation will accelerate inland across the Pacific Northwest coast through the northern intermountain region. This is expected to precede another impulse progressing inland across British Columbia and Pacific Northwest coastal areas by late Thursday night. ...Northern intermountain region... In association with the initial inland migrating impulse, it appears that modest mid-level cooling may contribute to steepening lapse rates across parts of the Columbia Valley and Plateau into the northern Rockies on Thursday. Coupled with at least some moistening, pockets of weak destabilization may contribute to convection capable of producing lightning. Although this is still expected to be fairly isolated and brief in nature, it is possible that the higher terrain of northeast Oregon and central Idaho into parts of western Montana could provide a focus for coverage exceeding 10 percent, mainly late Thursday afternoon into Thursday night. ..Kerr.. 03/07/2018 Read more



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