November 2014 Bering Sea cyclone

Meteorological history

Right after the JMA downgraded Nuri to a severe tropical storm at 00:00 UTC on November 6, the JTWC downgraded it to a tropical storm and issued its final warning for the system, due to Nuri's extratropical transition and diminishing deep convection. In the afternoon, Nuri accelerated northeastward and became completely extratropical east of Japan. Due to an unusually powerful North Pacific jet stream, the extratropical cyclone underwent extremely explosive cyclogenesis on November 7, owing to the energy from differences in air masses. The system split into two centers early on the same day, but the former center on the southwest was absorbed into the new center on the northeast, within half of a day.

After attaining hurricane-force winds at 70 knots (130 km/h; 80 mph), the new storm's central pressure decreased to 920 hPa (mbar; 27.17 inHg) early on November 8, becoming the most intense extratropical cyclone of the North Pacific Ocean since reliable records began. The U.S. National Oceanic and Atmospheric Administration provided a slightly higher estimate of 924 mbar (hPa; 27.29 inHg), a pressure which still holds the record for most intense cyclone in the Bering Sea. The extratropical cyclone crossed the International Date Line on November 9, at which time it started to weaken. However, the system's intensity shifted the jet stream far to the north of Alaska, resulting in a large mass of Arctic air invading the United States along and east of the Rocky Mountains, which caused the worst cold wave the United States had experienced since the Early 2014 North American cold wave. Early on the next day, the storm weakened further into a gale-force system and turned northward. On November 11, it turned northwestward, crossed the International Date Line for the second time, and weakened even further. Afterwards, the system made a counter-clockwise loop and crossed the International Date Line for the third time, late on November 12. The system eventually dissipated near the Aleutian Islands on November 13.