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 normal.

Africa Temperature

February's temperature 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.

larger image

Asia Temperature

larger image

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.

Australia Temperature

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/

larger image

U.S. Temperature

larger image

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.

Europe Temperature

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.

larger image

Wetness Anomalies in Africa

larger image

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.

larger image

Wetness Anomalies in Australia

larger image

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.

larger image

Wetness Anomalies in the United States

larger image

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 gradient.

larger image

Snow Cover Anomalies in the U.S.

larger image

Numerous storms (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 region.

Snow Cover in Europe

larger image

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 ...
SSMI Derived Products
Global Historical Climatology Network (GHCN)
The Blended GHCN - SSM/I Product
The Global Temperature Anomalies

Tom Ross
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4328
email: tom.ross@noaa.gov

David Easterling
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4328
email: david.easterling@noaa.gov

Mike Changery
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4328
email: mchangry@ncdc.noaa.gov

NCDC / Climate Monitoring / Climate of 1999 / Help