The IRI has prepared this experimental Climate Outlook for Australia for October 2001 - March 2002. Of relevance in the preparation of this outlook is the prediction of near-average to slightly warmer than average conditions in the eastern equatorial Pacific for the next 6 to 9 months. Currently the sea surface temperatures (SSTs) across much of the eastern and central equatorial are near their long-term average (SSTs), although slightly lower than average SSTs have developed along the immediate western coast of South America and warmer than average SSTs persist in the extreme western part of the basin. Near neutral equatorial Pacific SST conditions are in effect for the first season of the forecast, October-December 2001, November-January 2002, December-February 2002, while during the second season, January-March 2002, they are expected to be slightly above average. The warmer than average SSTs that continue to dominate much of the Indian Ocean are expected to decrease slowly through the forecast period. The area of above-average temperature in the tropical south Atlantic Ocean is expected to persist through at least the first half of the forecast period.

METHODS -

This Outlook was prepared using the following procedures and information:

A) Coupled ocean-atmosphere model predictions of tropical Pacific SST covering the forecast period. Particularly heavy weighting has been given to predictions from the coupled model operated by the NOAA National Centers for Environmental Prediction, Climate Modeling Branch. This model suggests a continuation of near-average conditions during the first forecast season. The forecast for near-neutral conditions is consistent with some, but not all, numerical and statistical forecasts of central and eastern Pacific SSTs.

B) Forecasts of the tropical Indian ocean using a statistical model developed by the IRI.

C) Global atmospheric general circulation model (GCM) predictions of the atmospheric response to the present and predicted sea-surface temperature patterns.

D) Other sources of information include NASA's Seasonal to Interannual Prediction Project (GSFC-NASA).

The procedures, models, and data used to derive this Climate Outlook may be somewhat different from those used by the national meteorological services in the region. Thus, this product may differ from the official forecasts issued in those areas. The Climate Outlook for October 2001 - March 2002 is dependent on the accuracy of the SST predictions. For the tropical Pacific, these predictions can be expected to provide useful information, but there is some uncertainty concerning the evolution of SSTs. Spread in global SST predictions is a source of uncertainty in the Outlook provided here. Note that even if perfectly accurate SST forecasts were possible, there would still be uncertainty in the climate forecast due to chaotic internal variability of the atmosphere. These uncertainties are reflected in the probabilities given in the forecast.

It is stressed that the current status of seasonal-to-interannual climate forecasting allows prediction of spatial and temporal averages, and does not fully account for all factors that influence regional and national climate variability. This Outlook is relevant only to seasonal time scales and relatively large areas; local variations should be expected, and variations within the 3-month season should also be expected. For further information concerning this and other guidance products, users are strongly advised to contact their National Meteorological Services.

OUTLOOK -

This Outlook covers four seasons: October-December 2001, November-January 2002, December-February 2002 and January-March 2002. Maps are given showing tercile probabilities of precipitation and temperature. The maps for precipitation indicate the probabilities that the seasonal precipitation will fall into the wettest third of the years (top number), the middle third of the years (middle number), or the driest third of the years (bottom number). The color shading indicates the probability of the most dominant tercile -- that is, the tercile having the highest forecast probability. The color bar alongside the map defines these dominant tercile probability levels. The upper side of the color bar shows the colors used for increasingly strong probabilities when the dominant tercile is the above-normal tercile, while the lower side shows likewise for the below-normal tercile. The gray color indicates an enhanced probability for the near-normal tercile (nearly always limited to 40%). As before, numbers and their associated histograms show the probabilities of the three terciles. In areas with lots of spatial detail, there may not be sufficient room on the map, to allow histograms for each region. In those cases, some idea of the probabilities may be gained from the color alone. A qualitative outlook of climatology ("C") indicates that there is no basis for favoring any particular category. Areas that are marked by "D" represent regions experiencing their dry season (less than 15% of annual precipitation) and for which less than 5cm of precipitation typically occurs over the season. Otherwise, for example, in the case of Tasmania, Victoria and parts of New South Wales in October-December 2001 (Map A), there is a 40% probability that the precipitation will be in the wettest third of the years, a 35% chance it will be in the near-normal third of the years, and a 25% chance that the precipitation will be in the driest third of the years.

Maps of temperature show expected probabilities that the seasonal temperatures will fall into the warmest third of the years, the middle third of the years, or the coldest third of the years (Map A). The numbers for each region on the temperature maps indicate the probabilities of temperatures to fall in each of the three categories, above-, near-, and below-normal.

An additional precipitation map is provided for the first season indicating probabilities for extreme precipitation anomalies. Extremes are defined as anomalies that fall within the top and bottom 15th percentile of the observed records. A priori, there is a 15% probability of being within the extremely wet category, and a 15% probability of being within the extremely dry category, leaving a 70% probability that the precipitation will not be extreme. The maps indicate areas of increased risk of extreme precipitation totals. Three levels of increased risk are defined: slightly enhanced risk, enhanced risk, and greatly enhanced risk. For slightly enhanced risk, there is a 25-40% probability that precipitation will be within the indicated extreme, i.e. wet or dry. This represents an approximate doubling of the climatological risk. For enhanced risk, there is a 40-50% probability that precipitation will be within the indicated extreme. This represents an approximate tripling of the climatological risk. For greatly enhanced risk, the probability that precipitation will be within the indicated extreme exceeds 50%, i.e. the indicated extreme is the most likely outcome. A similar map is provided in the first season indicating probabilities of extreme temperature anomalies.

Boundaries between sub-regions should be considered as transition zones, and their location considered to be only qualitatively correct.

October-November-December 2001:

Slightly enhanced probabilities for above normal precipitation (25%-35%-40%) are forecast for southeastern Australia, including Tasmania.

Slightly enhanced probabilities for near normal precipitation (30%-40%-30%) are forecast for part of southwestern Australia.

Slightly enhanced probabilities for below normal and near normal precipitation (40%-40%-20%) are forecast for southern New Guinea and the northern tip of Queensland, Australia.

Slightly enhanced probabilities for below normal precipitation (40%-35%-25%) are forecast for parts of Western Australia and Northern Territory, Australia.

Slightly enhanced probabilities for above normal precipitation (25%-35%-40%) are forecast for eastern Papua New Guinea.

Slightly enhanced probabilities for near normal precipitation (25%-40%-35%) are forecast for the Solomon Islands.

Slightly enhanced probabilities for near normal precipitation (35%-40%-25%) are forecast for much of central Indonesia.

Slightly enhanced probabilities for below normal precipitation (40%-35%-25%) are forecast for New Caledonia.

Slightly enhanced probabilities for below normal precipitation (40%-35%-25%) are forecast for much of northern Queensland, Australia.

An enhanced probability for below normal precipitation (45%-35%-20%) is forecast for Atuona, in northern French Polynesia.

Slightly enhanced probabilities for above normal temperature (25%-35%-40%) are forecast for various significantly large sectors of Australia.

Slightly enhanced probabilities for above normal temperature (25%-35%-40%) are forecast for part of Victoria, in southeastern Australia.

A very greatly enhanced probability for above normal temperature (10%-25%-65%) is forecast for northern New Zealand, surrounded by more weakly enhanced probabilities for above normal temperature in the remainder of New Zealand.

A greatly enhanced probability for above normal temperature (20%-30%-50%) is forecast for southern Tasmania, in southeast Australia, surrounded by more weakly enhanced probabilities for above normal temperature in the rest of Tasmania.

Slightly enhanced probabilities for above normal temperature (30%-30%-40%) are forecast for Chatham Island.

Slightly enhanced probabilities for near normal temperature (25%-40%-35%) are forecast for northern parts of Australia, and part of Indonesia.

Slightly enhanced probabilities for near normal temperature (30%-40%-30%) are forecast for Cocos Island.

Slightly enhanced probabilities for near normal temperature (30%-40%-30%) are forecast for much of Western Australia.

Slightly enhanced probabilities for near normal temperature (25%-40%-35%) are forecast for the Mascarene Islands.

Slightly enhanced probabilities for near normal temperature (25%-40%-35% and 30%-40%-30%) are forecast for much of eastern Australia.

A greatly enhanced probability for above normal temperature (15%-30%-55%) is forecast for western New Guinea, surrounded by more weakly enhanced probabilities for above normal temperature in the remainder of New Guinea, much of Indonesia, and some of the tropical Pacific Islands in the western Pacific.

November-December-January 2001-2002:

Slightly enhanced probabilities for above normal precipitation (30%-30%-40%) are forecast for Victoria, in southeastern Australia.

Slightly enhanced probabilities for near normal precipitation (35%-40%-25%) are forecast for a southern part of Western Australia.

Slightly enhanced probabilities for below normal precipitation (40%-35%-25%) are forecast for the western part of Western Australia.

Slightly enhanced probabilities for below normal precipitation (40%-30%-30%) are forecast for part of the Northern Territory, Australia.

An enhanced probability for above normal precipitation (15%-40%-45%) is forecast for Yap Island of the Federated States of Micronesia, surrounded by more weakly enhanced probabilities for above normal precipitation in Guam, United States.

An enhanced probability for below normal precipitation (45%-30%-25%) is forecast for part of Sumatra, surrounded by more weakly enhanced probabilities for below normal precipitation in additional portions of Sumatra and a small part of Malaysia.

Slightly enhanced probabilities for near normal temperature (25%-40%-35%) are forecast for part of the Philippines and much of Indonesia.

Slightly enhanced probabilities for above normal temperature (25%-35%-40%) are forecast for Cocos Island.

Slightly enhanced probabilities for above normal temperature (25%-35%-40%) are forecast for part of the Northern Territory of Australia and Western Australia.

An enhanced probability for above normal temperature (20%-35%-45%) is forecast for northern New Zealand, surrounded by more weakly enhanced probabilities for above normal temperature in central New Zealand.

Slightly enhanced probabilities for above normal temperature (25%-35%-40%) are forecast for southern Tasmania, of southeastern Australia.

Slightly enhanced probabilities for near normal temperature (25%-40%-35%) are forecast for much of Indonesia and northern as well as western Australia.

Slightly enhanced probabilities for near normal temperature (35%-40%-25% and 25%-40%-35%) are forecast for major parts of eastern and southeastern Australia.

Slightly enhanced probabilities for below normal temperature (40%-35%-25%) are forecast for part of southern and south-central Australia.

Slightly enhanced probabilities for below normal temperature (40%-35%-25%) are forecast for a small portion of Western Australia.

A greatly enhanced probability for above normal precipitation (15%-30%-55%) is forecast for certain tropical Pacific Islands in the western Pacific Ocean.

Slightly enhanced probabilities for near normal precipitation (25%-40%-35%) are forecast for Koror, Palau Island.

Slightly enhanced probabilities for below normal precipitation (40%-35%-25%) are forecast for southern Myanmar and portions of Thailand, Malaysia, and Indonesia.

December-January-February 2001-2002:

Slightly enhanced probabilities for above normal precipitation (30%-30%-40%) are forecast for a small region in southern Queensland and northern New South Wales, Australia.

Slightly enhanced probabilities for above normal precipitation (25%-35%-40%) are forecast for parts of New South Wales and Victoria, in southeastern Australia.

Slightly enhanced probabilities for below normal precipitation (40%-30%-30%) are forecast for New Caledonia.

Slightly enhanced probabilities for above normal precipitation (30%-30%-40%) are forecast for New Britian, New Guinea, and part of the Solomon Islands.

A greatly enhanced probability for above normal precipitation (15%-30%-55%) is forecast for certain tropical Pacific Islands in the western Pacific Ocean.

Slightly enhanced probabilities for near normal precipitation (25%-40%-35%) are forecast for Koror, Palau Island.

Slightly enhanced probabilities for below normal precipitation (40%-30%-30%) are forecast for western New Guinea and part of central Indonesia.

Slightly enhanced probabilities for below normal precipitation (40%-35%-25%) are forecast for parts of Myanmar, Thailand, Malaysia, and additional parts of Indonesia.

An enhanced probability for above normal temperature (20%-35%-45%) is forecast for part of Northern Territory and Western Australia, surrounded by more weakly enhanced probabilities for above normal temperature in additional portions of Australia from the west coast to Queensland.

Slightly enhanced probabilities for above normal temperature (25%-35%-40%) are forecast for southern New Zealnd.

Slightly enhanced probabilities for near normal temperature (25%-40%-35% and 35%-40%-25%) are forecast for extensive areas in Indonesia, as well as various parts of eastern, southern and northern Australia.

Slightly enhanced probabilities for below normal and near normal temperature (40%-40%-20%) are forecast for New Caledonia.

A greatly enhanced probability for above normal temperature (15%-30%-55%) is forecast for Yap Island of the Federated States of Micronesia, surrounded by more weakly enhanced probabilities for above normal temperature in Guam, United States, and more of the Northern Mariana Islands.

January-February-March  2001-2002:

An enhanced probability for above normal precipitation (25%-30%-45%) is forecast for southern Queensland and northern New South Wales, Australia, surrounded by more weakly enhanced probabilities for above normal precipitation in additional portions of those two divisions of Australia.

Slightly enhanced probabilities for above normal precipitation (30%-30%-40%) are forecast for northern New Zealand.

Slightly enhanced probabilities for near normal precipitation (35%-40%-25%) are forecast for Kermadec Island.

An enhanced probability for below normal precipitation (45%-30%-25%) is forecast for part of Northern Territory and northern Queensland, Australia, surrounded by more weakly enhanced probabilities for below normal precipitation in additional portions of those divisions of Australia.

Slightly enhanced probabilities for near normal precipitation (25%-40%-35%) are forecast for part of the Philippines, Brunei, Malaysia, and part of Indonesia.

Slightly enhanced probabilities for below normal and near normal precipitation (40%-40%-20%) are forecast for portions of Thailand, Malaysia and additional portions of Indonesia.

Slightly enhanced probabilities for below normal precipitation (40%-35%-25%) are forecast for portions of western New Guinea, Timor, and additional areas in Indonesia.

A greatly enhanced probability for above normal precipitation (20%-30%-50%) is forecast for the Northern Mariana Islands, Guam of the U.S., and Yap Island of the Federated States of Micronesia.

Slightly enhanced probabilities for above normal precipitation (25%-35%-40%) are forecast for eastern Kiribati (Fanning and Christmas Islands).

Slightly enhanced probabilities for near normal and above normal temperature (20%-40%-40%) are forecast for northern Queensland, Australia, and the Coral Islands.

An enhanced probability for above normal temperature (20%-35%-45%) is forecast for part of Western Australia, surrounded by more weakly enhanced probabilities for above normal temperature in additional parts of Western Australia and parts of South Australia and Northern Territory, Australia.

Slightly enhanced probabilities for near normal temperature (35%-40%-25% and 25%-40%-35%) are forecast for substantial portions of Indonesia as well as parts of mainly Northern Australia, southern and eastern Australia.

Slightly enhanced probabilities for near normal temperature (25%-40%-35%) are forecast for New Zealand.

A very greatly enhanced probability for above normal temperature (10%-30%-60%) i s forecast for Yap Island of the Federated States of Micronesia, surrounded by more weakly enhanced probabilities for above normal temperature in the Northern Mariana Islands, and Guam (of U.S.).

Slightly enhanced probabilities for near normal temperature (25%-40%-35%) are forecast for Taiwan, much of southeast Asia and much of Indonesia.

A very greatly enhanced probability for above normal temperature (10%-30%-60%) is forecast for the western Pacific centered near latitude 8N and longitude 148E, surrounded by more weakly enhanced probabilities for above normal temperature in Pohnpei and chuuk (Federated States of Micronesia), northeastern portions of New Guinea, and the northern Solomon Islands.

OBSERVED CLIMATOLOGY DATA for Oct-Nov-Dec, Nov-Dec-Jan, Dec-Jan-Feb and Jan-Feb-Mar

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