Please note: Material provided in this report is chosen subjectively and included at the discretion of the National Climatic Data Center (NCDC). The ability to report on a given event is limited by the amount of information available to NCDC at the time of publication. Inclusion of a particular event does not constitute a greater importance in comparison with an event that has not been incorporated into the discussion. Data included in this report are preliminary unless otherwise stated. Links to supporting information are valid at the time of publication, but they are not maintained or changed after publication.
In many areas around the globe temperature anomalies in
February 1999 followed the trend set in January. Unusually warm
conditions continued over southeast China and northern Indochina.
Temperatures were also above normal over portions of Russia, New
Zealand, northeast Africa, and the Middle East. In contrast, the
largest cold anomalies were observed over portions of Europe,
northwestern Africa, northern South America and northwest
Australia, where temperatures averaged 2-4 degrees C below
anomalies were similar to January 1999, although the warm/cool
anomaly structure was amplified across the northern section of the
continent. A strong trough in the east and a ridge to its west
promoted this pattern. The warm anomalies extended down into the
equatorial region. There was a contrast of warm and cold anomalies
in the southern quarter of the continent.
|Most of southern Asia
had above normal temperatures in February, with much of the area
more than 2 C above normal. The area of warm anomalies expanded
from January to February. Extreme southern regions of Indochina,
Indonesia and India were near to slightly below normal.
|New Zealand and the
surrounding south Pacific Ocean region continued to be warm with
some areas as high as 2 degrees C above normal. Temperatures across
east central Australia remained above normal this month, but values
were not nearly as extreme as January 1999. In contrast,
temperatures across west central Australia were quite cool,
reaching 4 degrees C below normal. These cooler conditions
coincided with a broad monsoon trough that developed in February.
Detailed analyses for Australia can be found at :http://www.bom.gov.au/climate/current/
|The majority of North
America continued to experience warmer than normal temperatures in
February. The upper Mississippi River valley and eastern Canada had
the largest anomalies. The warmth extended across the plains
states. Cooler than normal conditions occurred over most of the
Pacific coast, due to a persistent trough and onshore flow. This
pattern agrees in part with the anticipated winter pattern across
the U.S. and its association with La Niña, although there
are usually more arctic outbreaks into the northern portion of the
U.S. during a La Niña.
|A trough of arctic air
over Europe left most of the continent colder than normal for the
month. The coldest anomalies were centered in the Alps region,
where an excessive snow pack produced extensive avalanches. Extreme
northern and western countries had an onshore flow which allowed
for more moderate temperatures to dominate during the month.
Wetness Anomalies in Africa
|Surface wetness was
above normal in portions of the Central African Republic, northern
Zaire and Cameroon. Dry conditions continued over portions of
Ethiopia southward along the Rift Valley into Kenya and Tanzania.
The rainy season across portions of Namibia, Botswana, and South
Africa continued to be retarded this month, with most areas
experiencing below normal surface wetness.
Wetness Anomalies in Asia
|Low precipitation and
above normal temperatures in February worsened a drought over
southeastern China. East central India was also drier than normal
this month, although the region does not normally receive much
precipitation this time of year. Central India and parts of the
Ganges river valley exhibited above normal wetness for the second
month in a row.
Wetness Anomalies in Australia
|Areas of east central
Australia and eastern New Zealand continue to experience below
normal surface wetness. A broad monsoonal trough brought near
normal wetness to the western third of Australia, while it remained
drier than normal in the far south west corner. Detailed analyses
for Australia can be found at :http://www.bom.gov.au/climate/current/
Wetness Anomalies in Europe
|A persistent trough
over northwestern Europe allowed above normal wetness in west
central Europe, from France to Germany. Further to the south the
air was moisture deprived, causing the Mediterranean states to be
drier than normal. A persistent northerly flow over Europe kept the
region relatively dry, which is illustrated by the negative
anomalies over the Iberian Peninsula. It was also dry to the north,
but melt water in the snow pack produced positive anomalies.
Further to the east, the snow pack did not undergo any significant
melting; therefore liquid water was not observed, and the wetness
anomalies are once again negative. A southwest flow to the east of
the main trough axis brought much needed water to the Ukraine and
areas surrounding the Black Sea, but it remained dry further to the
east, in southern Russia.
Wetness Anomalies in the United States
|The storm track
produced wetter than normal conditions from the Texas Panhandle,
across Oklahoma, into parts of the Ohio Valley. It was also wetter
than normal across portions of the Pacific Northwest coast, but
most of the precipitation at higher elevations fell in frozen form
and remained frozen, and thus was not observed as liquid water. In
contrast, a lack of Gulf of Mexico moisture kept portions of Texas
and the immediate Gulf coast drier than normal. Most of the
northwest coast and the eastern seaboard was wetter than normal,
unfortunately, the forest cover obscured the wetness signal from
the satellite sensor. Therefore these and other heavily vegetated
areas do not provide reliable wetness observations.
Percent Snow cover in the U.S.
|This snow cover map is
directly related to the general temperature pattern and storm track
across the U.S during the month. Snow cover was persistent in
mountain areas across most the west. Since most of the moisture was
squeezed out by the mountains, the high plains had a lot less snow
cover. In the eastern half of the country, the northern sections
were persistently snow covered. This snow cover rapidly diminished
further south, resulting in a strong north-south snow cover
Snow Cover Anomalies in the U.S.
(typical of a La Niña pattern) slammed into the Pacific
Northwest coast this month. Snow cover anomalies were well above
normal along the storm track from portions of northwestern North
America into the northern Plains. In contrast, a weaker than normal
sub- tropical jet stream brought below normal snow cover across
portions of the Four Corners area and the lower Plains. The lack of
snow cover in the eastern part of the U.S. was related to above
normal temperatures, which led to more rain than snow events in the
Snow Cover in Europe
|A persistent trough in
western Europe brought cold Arctic air to eastern and central
Europe, and it was reflected by the above normal snow pack. This
abundant snow pack resulted in numerous avalanches and fatalities
during the month. In contrast, further to the east, a southwest
flow brought warm temperatures and fewer than normal days with snow
over southeatern Ukraine and the countries along the southern
border of Russia and the Black Sea.
Basist, A., N.C. Grody, T.C. Peterson and C.N. Williams, 1998:
Using the Special Sensor Microwave/Imager to Monitor Land Surface
Temperatures, Wetness, and Snow Cover. Journal of Applied
Meteorology, 37, 888-911.
For more information, refer to ...
Climatology Network (GHCN)
GHCN - SSM/I Product
Global Temperature Anomalies