1. Northern Hemisphere
circulation during November featured above-average heights across the central
North Pacific, much of Canada, and Scandinavia, and below average heights over
the Gulf of Alaska and the eastern North Atlantic (Fig.
E9). Regional aspects of the circulation included
a nearly complete disappearance of the mean Hudson Bay trough, and a very strong
flow of mild, marine air into central and northern Europe.
temperature signals during November included above average temperatures across
Canada, the north-central United States, and Europe, and below average
temperatures in central Russia (Fig. E1).
The main precipitation signals during the month included above-average totals in
northern Europe and eastern China, and below-average totals across the United
States and eastern Canada (Fig. E3).
a. North Pacific/
circulation during November featured negative height anomalies in the Gulf of
Alaska and western Canada, and positive height anomalies across eastern North
America (Fig. E9).
This anomaly pattern reflected a deep trough over the Gulf of Alaska, a much
weaker than average ridge over western North America, and nearly a complete
disappearance of the mean Hudson Bay trough (Fig.
E9). This overall pattern was associated with an
anomalously zonal flow across continent, which contributed to above average
surface temperatures across Canada and the north-central U.S. (Fig.
largest temperature departures were observed Canada, where values exceeded +5°C
and were in the upper 90th percentile of occurrences. Much of North
America also recorded below average precipitation during November, with the most
significant deficits occurring in the East in response to a reduced strength of
the Hudson Bay trough (Fig. E3).
circulation during November featured an anomalous trough-ridge couplet over the
eastern North Atlantic and Scandinavia (Fig.
E9). This pattern allowed for an extensive flow of
marine air into the continent, which resulted in above average temperatures
throughout Europe, Scandinavia, and western Russia (Fig.
E1). The largest departures (+3° to 4°C) were
observed in northern Europe and western Russia, with much of Europe recording
values in the upper 90th percentile of occurrences. The strong
onshore flow and associated increase in storminess also contributed to above
average precipitation in northern Europe, with totals in Great Britain exceeding
the 90th percentile of occurrences (Fig.
2. Southern Hemisphere
500-hPa circulation during November featured above average heights over the
central South Pacific and in the areas south of Australia and South Africa, and
below average heights near New Zealand, over southern South America, and across
the central South Atlantic (Fig. E15).
The main temperature anomalies during November reflected warmer than average
conditions in central South America and southeastern Australia, and cooler than
average conditions in southern South America (Fig.
E1). The main precipitation signals during the
month reflected above average totals in southeastern South America and portions
of southeastern Australia, and a continuation of below average totals in
northeastern Australia (Fig. E3).