The Tonga Volcano VEI classification is certain to be at least 4 and possibly 5 which automatically qualifies the volcano as a likely influencer of global climate. Early speculation is that Tonga is the strongest volcanic eruption since Pinatubo in 1991.

A major storm moves north-northeast through the Atlantic Seaboard later today and Monday. The storm is unusually intense (976 MB in northern New Hampshire by tomorrow evening) due to entrainment of moisture off the somewhat warmer than normal ocean surface of the Gulf of Mexico and western North Atlantic and the subsequent clash from arctic air from Quebec. A series of major hazards to the East U.S. is caused by this storm.

A pattern change is indicated for the second half of January. Previously, a semi-permanent upper trough was located southeast of Brazil and enhancing historic rainfall for that nation the past couple months. The GFS 15-day outlook indicates a pattern change. An upper-level ridge crests just-off the far southeast coast of Brazil. The result is wetter weather for Argentina and drier/warmer climate for Brazil.

In today's midday update the 12Z GFS produces several major winter events driven by a strong -NAO pattern. First, an arctic gale on the New England Coast Friday night. Second, a late weekend East Coast snowstorm. Third, low latitude ice storm risk centered on Texas later next week.