Note: The data presented in this report are preliminary. Ranks and anomalies may change as more complete data are received and processed. Effective September 2012, the GHCN-M version 3.2.0 dataset of monthly mean temperature replaced the GHCN-M version 3.1.0 monthly mean temperature dataset. Beginning with the August 2012 Global monthly State of the Climate Report, released on September 17, 2012, GHCN-M version 3.2.0 is used for NCDC climate monitoring activities, including calculation of global land surface temperature anomalies and trends. For more information about this newest version, please see the GHCN-M version 3.2.0 Technical Report.
*The GHCN-M version 3.1.0 Technical Report was revised on September 5, 2012 to accurately reflect the changes incorporated in that version. Previously that report incorrectly included discussion of changes to the Pairwise Homogeneity Algorithm (PHA). Changes to the PHA are included in version 3.2.0 and described in the version 3.2.0 Technical Report. Please see the Frequently Asked Questions to learn more about this update.
The above figure shows June 1999 temperature anomalies
calculated from available in-situ stations using an 1880 - 1998
base period. Temperature anomalies are absent from several areas of
the globe due to a lack of reporting stations. To improve spatial
coverage of global temperature anomalies, satellite data has been
combined with in-situ station records in the spatial temperature
plot below.
Temperature
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Preliminary mean
monthly temperature anomalies (using a base period 1880-1998) for
June are shown in the figure to the left. June 1999 land and ocean
temperatures were much lower than the record values recorded in
1998, but temperatures remained above the long term mean for the
23rd year in a row. This continues a trend to lower monthly
anomalies that began with the end of El Niño in 1998.
The average temperature over land and ocean was 0.33 C above the
mean, the fourth coolest June this decade. Although both land and
sea surfaces were much cooler in June 1999, when compared to June
1998 temperatures, the trend toward cooler temperatures continued
to occur at a faster rate over ocean surfaces. The sea surface
temperature anomaly fell from 0.51 C in June 1998 to 0.22 C in
1999. Global land temperatures averaged 0.58 C above the long term
mean in June 1999, 0.32 C cooler than in June 1998. |
| The extremely warm
temperatures in Scandinavia and Eastern Europe were the dominant
feature in June. These anomalies were associated with a persistent
upper level ridge that covered the region for almost the entire
month. Also noteworthy were the cold sea surface temperature
anomalies that have persisted in the east equatorial Pacific for
almost a year. These anomalies are associated with La Niña
conditions that continue to prevail over the tropics. Another
feature in June was the warm anomalies in north eastern North
America, where temperatures averaged much above normal and which
was associated with an upper level ridge. |
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| Warmer than average
temperatures also covered much of northern Africa, central Asia and
southeastern Brazil. A trough over a portion of central Russia kept
that area cooler than average. It was also colder than usual in
northern Mexico and the central plains of the United States in
association with above average cloud cover and above average
precipitation. Some cold air outbreaks influenced eastern Australia
during this winter month in the Southern Hemisphere.
The atmospheric circulation anomaly pattern for June 1999 is
available for the Northern Hemisphere
and Southern
Hemisphere.
See the U.S. Regional / Statewide
Analyses pages and the Global
Regional Analyses pages for more details on regional climate in
the United States and throughout the world.
|
Precipitation
| As shown in the
adjacent figure, global precipitation (land only) averaged below
the long term mean (1900-1998), indicating global reporting
stations were generally drier than average in June. The average
anomaly was 2.8 mm (0.11 in) below the long term mean, 4.2 mm (0.16
in) less than in June 1998. |
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Above average
precipitation was widespread in only a few areas of the world in
June. Conditions were wetter than average in a band from the
central plains to the southeastern United States. A persistent low
pressure trough also brought above average precipitation in an area
that stretched from Great Britain through much of Scandinavia.
Above average rainfall also stretched from the Baltics to the
western two-thirds of Turkey. The majority of Korea and Japan was
also wetter than average in June. The largest positive anomalies
(greater than 250 mm (10 in)) were recorded in parts of western
India. |
| A large band of drier
than average conditions stretched from Portugal across the
Mediterranean to the Middle East. Parts of the Middle East
continued to endure a drought that has damaged crops and forced the
implementation of water use restrictions. Drought conditions also
prevailed across much of the Sudan region of Africa as
precipitation was again below average in June. Much of western
Russia was also drier than average in June, as a dominant upper
level ridge suppressed precipitation. Large areas of below average
precipitation are also shown in much of eastern China, the eastern
third and western border of Brazil, and the northeastern part of
the United States. |
Global Surface Wetness
| The snow cover in
extreme northeastern Canada normally melts in June. However due to
unusually cold weather it persisted later into the summer, leaving
below average wetness values on the surface. Further southward, the
snow, which normally melts in May, lingered until June, resulting
in above average wetness values this month. |
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In contrast, the below average June wetness in north central Russia
corresponded with unusally warm May temperatures and a premature
melting of the snow pack. The plains states of the central U.S.
were in an active storm track, keeping the area wetter than usual.
The region north of the Black Sea and much of eastern Argentina
were drier than average. There were spotty areas of positive wet
anomalies over northern Mexico, India, and central China. Spotty
areas of dry anomalies were evident over part of India, eastern U.
S., northern China and the Sahel in Africa.
