1. Northern Hemisphere
The 500-hPa circulation
pattern during November featured persistent positive height anomalies in the
western
U.S.
, in the area south of
Greenland
, and from northwestern
Russia
to eastern
Siberia
, and persistent negative height anomalies over the western and central
North Pacific (Figs. E9, E11).
The main surface temperature departures reflected above-average temperatures
across central
North America
, in the high latitudes and subtropical latitudes of the
North Atlantic
, and across northern and eastern
Eurasia
(Fig. E1). The main precipitation departures
included above-average totals in the northeastern
U.S.
and eastern
Canada
, and below-average totals in the south-central
U.S.
and portions of both eastern Europe and central
Russia
(Figs. E3, E5, E6).
a.
North America
During November, a persistent
pattern of above-average heights at 500-hPa covered western
North America
(Figs. E9, E11),
and contributed to exceptionally warm temperatures over large portions of
Canada
and the
United States
. The largest positive temperature departures were observed in
Canada
, where monthly temperatures averaged 3°-4°C warmer than normal. In the
north-central
U.S.
, monthly temperatures averaged 2°-3°C warmer than normal. For both
regions, these anomalies were above the 70th percentile of
occurrences.
Precipitation was below
average (in the lowest 30th percentile of occurrences) in the
Southwest and
Gulf
Coast
regions of the
U.S.
, and in portions of eastern Europe (Fig. E3).
Each of these areas was situated in anomalous descending motion between the
mean upper-level ridge and trough axes (Fig. E9).
b.
North Atlantic Hurricanes
The extremely active 2005
Atlantic hurricane season produced an additional three named storms during
November (TS Beta, TS Delta, H Epsilon), with all occurring during the
second half of the month. By the
end of November, the 2005 season had featured a record 26 named storms, a
record of 14 hurricanes, and 7 major hurricanes. The previous record of 21
tropical storms was set in 1933, and the previous record of 12 hurricanes
was set in 1969.
c. Europe
/
Eurasia
The 500-hPa circulation
pattern during November featured a persistent pattern of positive height
anomalies over the central
Atlantic
, and extending from western
Russia
to
Siberia
(Fig. E11). These conditions were
associated with a pronounced split-flow pattern over
Europe
. They were also associated with an enhanced poleward transport of
relatively mild, maritime into northern
Europe
and
Scandinavia
within the northern branch of the split-flow. This anomalously warm air
overspread much of
Russia
, resulting in the well above-average temperatures from
Europe
to eastern
Siberia
. The most anomalous warmth
occurred across
Scandinavia
and northwestern
Russia
, where temperatures were 4°-7°C above average.
2. Southern Hemisphere
The mean 500-hPa circulation pattern during November
featured above-average heights southeast of Australia and over the high
latitudes of the eastern South Pacific, and below-average heights southwest
of Australia, over the central South Pacific, and across southern South
America and the western South Atlantic (Fig. E15).
Positive surface temperature anomalies were observed over the eastern half
of
Australia
and most of
South America
, with monthly mean temperatures in both regions exceeding the 70th
percentile of occurrences.
In southern
Africa
the rainy season normally lasts from October to April. Rainfall was slightly
above average in this region during November, following well above-average
rains during October (Fig. E4). In November,
the largest positive rainfall anomalies occurred in southeastern
South Africa
, and near-normal totals occurred elsewhere.
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