Extratropical Highlights –November 2022

 

1. Northern Hemisphere

The 500-hPa circulation during November featured strongly above-average heights over the North Pacific Ocean and the Greenland Sea, and strongly below-average heights south of Greenland over the North Atlantic Ocean (Fig. E9). The main land-surface temperature signals include above-average temperatures in Europe, Southeast Asia, eastern Russia, Alaska and the Northwest Territories of Canada, and below-average temperatures in western Canada and the U.S. West Coast (Fig. E1). The main precipitation signals include below-average totals along western North America and the Great Lakes region, and above-average totals in parts of Asia (Fig. E3).

 

a. North America

The 500-hPa circulation during November featured an amplified ridge over the North Pacific Ocean that ushered in below-average temperatures and drier than average conditions for western Canada and the western United States (Figs. E1, E9).  Departures of precipitation from normal reached the lowest 30th percentile of occurrences (Fig. E1). Below-average rainfall was also observed across the Great Lakes region and above-average rainfall was recorded for parts of the Gulf Coast, and predominantly for the coastal areas of Texas (Fig. E3).

 

b. Europe and Asia

The 500-hPa circulation during November featured an amplified ridge over the Greenland Sea and an amplified trough south of the ridge and over the North Atlantic Ocean (Fig. E1).Temperatures were strongly above-average for Europe with most of the area reaching the highest 90th percentile of occurrences or greater (Fig. E1). Above-average temperatures were also observed in Southeast Asia and western portions of Russia (Fig. E1). Precipitation was near-normal for much of Europe, central Russia, and Asia (Fig. E3).  Isolated regions in the Middle East and Southeast Asia observed above-average rainfall with some areas recording totals in the 90th percentile of occurrences (Fig. E3).

 

c. Atlantic hurricane season

The 2022 Atlantic hurricane season produced 14 named storms, with eight becoming hurricanes and two of those becoming major hurricanes. The 2022 Accumulated Cyclone Energy (ACE) value was about 98% of the 1951-2020 median. Based on this activity, NOAA classifies the season as being near normal. This ends the streak of consecutive above-normal seasons at 6 (2016-2022). An average season has 14 named storms, 7 hurricanes, and three major hurricanes.  The third named storm of the season, Tropical Storm Colin, developed around the time the third named storm is normally declared. Then activity was absent from July 2 until Hurricane Danielle developed on Sept 1. An August devoid of hurricane activity is rare, last occurring in 1982. Activity during September ramped up with six named storms developing, including the devastating Hurricane Ian. Damage estimates from Ian are still being calculated, and are likely to top 100 billion USD. November was unusually active, with two hurricanes. Normal activity for November is defined as one storm, every other year. The near-normal activity was at the low-end of the predicted ranges, inconsistent with prior years that were also defined by a warm AMO, La Nina, and a robust West African Monsoon circulation. Those traditionally, when aligned in a reinforcing manner, produce very active years. The quiet August period was not predicted at the start of the season, but the potential for an extended season was mentioned in outlooks. Late season activity is often elevated during La Nina years.

 

2. Southern Hemisphere

The 500-hPa height field during November featured an amplified annular wave-train pattern with a center of moderate to strongly below-average heights over Antarctica (Fig. E15). In southern Australia, heights were slightly below-average while temperatures were also below-average and precipitation was above-average in the north and south with totals reaching the 90th percentile along the respective coasts (Figs. E1, E3).  Off the east coast of South America was an amplified ridge that likely contributed to the moderate to strongly above-average temperatures and drier than normal conditions for Argentina and Chile (Figs. E1, E9, E15).

The South African monsoon season runs from October to April. During November 2022, much of this area recorded above-average precipitation (Fig. E3), and area-averaged totals were at or above the highest 90th percentile of occurrences (Fig. E4).

The Antarctic ozone hole typically develops during August and reaches peak size in September. The ozone hole then gradually decreases during October and November, and dissipates on average in early December (Fig. S8 top). During 2022, the ozone hole was predominantly above the 2012-2021 mean and was near average size by the end of November.  The polar vortex was also above-average for November (Fig. S8 middle) while polar stratospheric clouds were near normal conditions for November and largely absent (Fig. S8 bottom).