 Temperature
Mean monthly temperature anomalies for February (using
a base period 1880-1998) are shown in the figure above. The mean
monthly land temperature anomaly for February 1999, 1.18 degrees C,
was well above the 1880-1998 average temperature. However, this was
over 0.4 degrees C below last year's February mean global land
temperature. The ocean temperature anomaly for February 1999, 0.28
degrees C, exhibits a similar drop from the 1998 value, which
correspondes to the shift from warm to cold water in the east
equatorial Pacific Ocean. The combined land and sea surface
temperature anomaly for February 1999, 0.55 degrees C, shown in the
top time series, remained well above the mean value, but it
exhibits a considerable drop from the February 1998
value.
| This figure shows the
spatial distribution of land surface temperature anomalies in
February 1999. Most areas of world experienced temperatures above
their long term means (1880-1998). Much above average temperatures
(>5 C) were widespread throughout the central US as well as
parts of Canada and Russia. Temperatures in the central
United States were 5.4 C above average in February. This was
the second warmest mean temperature anomaly for this area of the
US, second only to the 6.5 C anomaly which occurred in 1954. |
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Large negative anomalies (<-5 C) were recorded in Alaska, while
small negative anomalies were scattered throughout parts of Europe.
Below average temperatures were also widespread along the
southeastern and northwestern coasts of Australia as well as
southwestern areas of Africa.
Precipitation
| Rainfall in mid and
high latitude areas of the Northern Hemisphere averaged near
normal. Areas in the 85N-55N latitude band averaged 3.71 mm (0.15
in) above the long term mean. This was a decrease of over 4 mm from
last February's average value, and well below the highest average
of 20.09 mm which occurred in 1997. Precipitation in the
mid-latitude band (55N-30N) was 3.43 mm (0.14 in) below the
long-term mean and over 10 mm below last year's average. The
greatest negative anomaly for February precipitation in this
latitude band was in 1995 at nearly -9.5 mm below the long-term
mean. |
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Further south in the 30N to 10N latitude band, the
precipitation anomaly was -6.7 mm versus 7.3 mm recorded in
February 1998. The record negative anomaly for February
precipitation in this latitude band was -18.9 mm (0.74 inches) in
1902.
Precipitation patterns that occurred in January 1999
were also predominant in the month of February. Above
normal sea surface temperatures in the southwest Pacific
continued to enhance precipitation throughout the southwest Pacific
Islands.
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February precipitation
was 153 mm (6.0 inches) above the long term mean for this
area. This was 298 mm (11.7 inches) more than fell during
February 1998 when precipitation was limited due to the effects of
El Niño. Further to the north, precipitation was below
average across Japan, Korea and eastern areas of China as a ridge
of high pressure continued to restrict the flow of moisture to
these regions. There was also below average precipitation
throughout the eastern two thirds of the United States. |
Precipitation was more than 3 inches below average in
many areas of the southeastern US. This was in sharp contrast to
areas of the northwestern US that were much wetter than normal.
Precipitation in the state of Washington was 100 mm (4.0 in) above
average in February. Above average precipitation was also
widespread throughout Europe. The precipitation was in the form of
snow in the mountains of Italy and Switzerland and contributed to
numerous avalanches that resulted in substantial destruction of
property and loss of life. For more information, see Extreme
Events
Global Surface Wetness
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Surface wetness was
above normal in February in some portions of central U.S.,
equatorial Africa, central India, and western Europe. In contrast
to these few locations, there were many larger areas with below
normal wetness. Many sections of southern Africa and eastern
Australia were much drier than normal. There were also extensive
areas of dry conditions in eastern China and portions of central
U.S. The persistence of unmelting snow cover in eastern Europe
resulted in less surface wetness in that area than is normal for
February. |
Global Snow Cover
| This snow cover
anomaly map indicates areas which had more days with snow cover
than is normal for the month (indicated as a positive anomaly with
shades of green and blue) as well as areas which had fewer than
normal days with snow cover (indicated as a negative anomaly by
shades of yellow and red). |
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Above normal days with snow cover was found over the central west
coast of North America. This positive anomaly extended into the
northern plains. In contrast, there were fewer than normal days
with snow cover further south and east. Positive snow cover was
also found through most of central Europe, while there were fewer
than normal days in the southeastern Ukraine and along the southern
border of Russia. Over Asia there were small areas of both positive
and negative anomalies.
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