IRI Climate Digest December
November Global Climate Summary
Climatological Background In December,
the Northern Hemisphere enters the heart of winter, with strong north-south
temperature differences driving the mid-latitude jet stream and storm systems.
In the Southern Hemisphere summer is under way, with monsoon systems gaining
strength in South America, southern Africa, and Australia.
Monthly Mean Temperature (1961-1990), data from the Climate Research
Unit, University of East Anglia
DATA: Univ. of East Anglia
|Monthly Mean Precipitation (1961-1990), with data from
the Climate Research Unit, University of East Anglia
DATA: Univ. of East Anglia
Temperatures Over Land
Temperatures continued well below average over much of North America
and northern Asia for the second straight month. By contrast, continental
Europe has remained unusually warm since October.
North America: Unusually cold conditions prevailed across
central Canada and most of the central and eastern United States.
In the US, the national average temperature for the November-December period
was the lowest on record. Meanwhile, Alaska was unusually mild, with
temperatures as much as 8 C above average in western sections.
Asia: Unusually cold conditions continued across the Central
Siberian Uplands southward into Mongolia. China and western Asia
were unusually warm with temperatures from the Baltic states northward
to Finland as much as 4 C above average.
Europe: Unusually warm conditions have persisted across
most of continental Europe since October.
Africa: Warmer than average conditions continued along
coastal regions of West and North Africa.
Australia: Unseasonably warm conditions continued along
the southern coast while below average temperatures prevailed across much
of the northern parts of the continent.
South America: Temperatures were somewhat higher than
average from Ecuador northward to Colombia and Venezuela.
|Temperature Difference from the 1961-1990 mean, with
data from NCEP Climate Prediction Center, CAMS.
NOAA NCEP CPC CAMS anomaly temperature anomaly
Unusually heavy rainfall continued across western Indonesia, northern
Australia and the Philippines. Intense rains plagued the Iberian
Peninsula as storminess in western Europe continues.
Indonesia: Following heavy rains and flooding in November,
intense rainfall continued into December in Sumatra.
Europe: Very heavy rainfall fell across Portugal and northern
Spain. Northern France and northern Italy were also unusually wet while unseasonably dry conditions prevailed across the southeast.
Africa: Rainfall across southern Kenya,Tanzania
the Lake Victoria Basin helped ease earlier drought conditions. Above
average rainfall was observed across much of Zambia.
Philippines: Tropical cyclone activity brought more heavy
Australia: In regions already experiencing unusually wet
conditions, heavy rainfall fell across northern sections of the Northern
Territory and Queensland.
South America: Near-average precipitation was observed
across the continent with unusually heavy rainfall confined primarily to
central and eastern Brazil.
North America: Unusually dry along the west coast and
southeastern United States.
Caribbean: Above-average rainfall across the central Caribbean.
Heavy rainfall in Jamaica and central Cuba helped ease a prolonged dry
|Precipitation Difference from 1961-1990 mean, with
data from NCEP Climate Prediction Center, CAMS-OPI.
NOAA NCEP CPC CAMS_OPI v9906 anomaly Precipitation Anomaly (mm/day).
Contours 0.5, 2, 4, 6, 8,...
Tropics: Surface temperatures in the eastern and central
Pacific remained somewhat below average indicating continued, but weak,
La Nina conditions. The western Pacific and central
Indian oceans remained unusually warm during the month.
Midlatitudes: Above average water temperatures persisted
to the south of Australia. Warmer than average conditions developed
along coastal areas of southern Africa and persisted in the Sea of Japan
and the central North Atlantic.
Monthly Sea Surface Temperature Difference from the 1950-1979 mean,
with data from the Environmental Modeling Center, NCEP/NOAA.