The IRI has prepared this experimental Climate Outlook for Australia for August 2001 - January 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, August-September-October 2001, September-October-November 2001, October-November-December 2001, while during the second season, November-December 2001-January 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 August 2001 - January 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: August-September-October 2001, September-October-November 2001, October-November-December 2001 and November-December 2001-January 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 much of Western Autralia in August-September-October 2001 (Map A), there is a 30% probability that the precipitation will be in the wettest third of the years, a 30% chance it will be in the near-normal third of the years, and a 40% 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.

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

August-September-October 2001:

The following regions of enhanced probabilities of precipitation anomalies are indicated:

Enhanced probabilities for below-normal precipitation (20%-35%-45%) are forecast for southern Sumatra, most of Java, and southwestern Borneo. Surrounding this region are slightly enhanced probabilities for below-normal precipitation (25%-35%-40%) extending over much of Sumatra, and much of Borneo and Malaysia.

Slightly enhanced probabilities of near-normal precipitation are forecast throughout much of Indonesia from the Celebes to Papua New Guinea.

Within the above mentioned region, there is an area of slightly enhanced probabilities for above-normal precipitation (25%-35%-40%) over much of the Papua New Guinea islands.

Slightly enhanced probabilities for above-normal precipitation (30%-30%-40%) and (25%-35%-40%) over the southern Philippines Islands and southward toward the Banda Sea.

Slightly enhanced probabilities for above-normal precipitation (25%-35%-40%) over Kiribati.

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

Slightly enhanced probabilities for above-normal precipitation (30%-30%-40%) are forecast over North Island and northern South Island of New Zealand.

Slightly enhanced probabilities for below-normal precipitation (40%-35%-25%) and (40%-30%-30%) are forecast for parts of Western Australia, Northern Territory, South Australia, and New South Wales in Australia.

Slightly enhanced probabilities for above-normal precipitation (30%-30%-40%) are forecast for part of coastal Victoria and northern Tasmania.

The following regions of enhanced probabilities of temperature anomalies are indicated:

Strongly enhanced probabilities of above-normal temperature (15%-30%-55%) are forecast for the Philippines and northern Malaysia. This region then extends east/southeastward with generally weaker, but still enhanced, probabilities for above-normal temperature over the Indonesian region east of about 125E, including all of New Guinea, the Solomon Islands, New Caledonia, the Caroline Islands, and other western tropical Pacific islands, west of approximately 160W.

Slightly enhanced probabilities for near-normal to above-normal temperature (25%-40%-35%) are forecast for the Malaysian peninsula, Sumatra, Java, and much of Borneo and the Celebes.

Slightly enhanced probabilities for near-normal to above-normal temperature (25%-40%-35%) are forecast for northernmost Northern Territory in Australia.

Slightly enhanced probabilities for below-normal temperature (40%-35%-25%) are forecast for parts of northwestern coastal Western Australia.

Slightly enhanced probabilities for near-normal to below-normal temperature (35%-40%-25%) are forecast for southwestern Western Australia.

Enhanced probabilities for below-normal temperature (45%-35%-20%) are forecast for southwestern Queensland. To the west and south of this region, slightly enhanced probabilities for below-normal temperature (40%-35%-25%) are forecast for must of the rest of Queensland, Australia.

Strongly enhanced probabilities for above-normal temperature (20%-30%-50%) are forecast for North Island of New Zealand, and enhanced probabilities for above-normal temperature (20%-35%-45%) are forecast for South Island of New Zealand.

September-October-November 2001:

The following regions of enhanced probabilities of precipitation anomalies are indicated:

Enhanced probabilities for below-normal precipitation (45%-35%-20%) are forecast for southern Sumatra, much of Java and the southern coast of Borneo. Surrounding this region are weaker probabilities favoring below-normal precipitation.

Slightly enhanced probabilities for above-normal precipitation are forecast over much of the Philippines and southward as far as Timor.

Slightly enhanced probabilities for near-normal precipitation are forecast over northern Northern Territory in Australia and over southern New Guinea.

Slightly enhanced probabilities for below-normal precipitation (40%-35%-25%) are forecast over northern Western Australia and also over parts of Victoria, New South Wales, and southwestern South Australia.

Slightly enhanced probabilities for above-normal precipitation (25%-35%-40%) over much of eastern Queensland.

Slightly enhanced probabilities for above-normal precipitation (30%-30%-40%) are forecast over southern North Island and northern South Island of New Zealand.

Enhanced probabilities of above-normal temperature (20%-35%-45%) are forecast for much of the Philippines. Neighboring regions are forecast with slightly enhanced probabilities for above-normal temperature (25%-35%-40%).

The eastern half of the Indonesian islands, east of about 130E, and northern Australia and the tropical western Pacific islands from 20S-20N and extending to about 160W are forecast with enhanced probabilities for above-normal temperature.

Slightly enhanced probabilities for below-normal temperature (40%-35%-25%) are forecast for southwestern Western Australia.

Strongly enhanced probabilities for above-normal temperature (15%-35%-50%) are forecast for all of New Zealand.

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

October-November-December 2001:

The following regions of enhanced probabilities of precipitation anomalies are indicated:

Enhanced probabilities for below-normal precipitation (from 40%-35%-25% to 50%-30%-20%) are forecast over Java and the southern half of Sumatra.

Strongly enhanced probabilities for above-normal precipitation (20%-30%-50%) are forecast for an area over the islands of Halmahera and Buru between the Celebes and Banda Sea. Surrounding this region are weaker enhanced probabilities for above-normal precipitation covering the Philippines, northern Malaysia, including Brunei, and eastern Borneo, the Celebes and extending over the Banda and Timor Sea.

Enhanced probabilities for above-normal precipitation (20%-35%-45%) are forecast for the Caroline Islands.

Slightly enhanced probabilities fo above-normal precipitation (25%-35%-40%) are forecast for Papua New Guinea and the Solomon Islands.

Slightly enhanced probabilities of near-normal to above-normal precipitation (25%-40%-35%) are forecast for Vanuatu and New Caledonia.

Slightly enhanced probabilities for near-normal to above-normal precipitation (25%-40%-35%) are forecast for Tuvalu.

Enhanced probabilities for below-normal precipitation (45%-35%-20%) are forecast for parts of Western Australia. Surrounding this region are slightly enhanced probabilities for below-normal precipitation (25%-35%-40%).

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

Slightly enhanced probabilities for below-normal temperature (40%-35%-25%) are forecast for southernmost Thailand, most of Malaysia, Borneo, Sumatra, and western portions of Java.

Slightly enhanced probabilities for above-normal temperature are (25%-35%-40%) are forecast for the southern islands of the Philippines, and extending south-eastward over western New Guinea.

Strongly enhanced probabilities for above-normal temperature (20%-30%-50%) are forecast for the Caroline Islands.

Slightly enhanced probabilities of above-normal temperature are forecast for much of Papua New Guinea, the Solomon Islands, and New Caledonia.

Strongly enhanced probabilities for above-normal temperature (20%-30%-50%) are forecast for the western-central tropical Pacific islands (about 160E-160W).

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

Slightly enhanced probabilities for below-normal temperature (40%-35%-25%) are forecast for southwestern Western Australia.

Slightly enhanced probabilites for above-normal temperature (20%-40%-40%) are forecast for much of New Zealand, with stronger probabilities for above-normal temperature (25%-35%-45%) over southern South Island.

November-December 2001-January 2002:

The following regions of enhanced probabilities of precipitation anomalies are indicated:

Slightly enhanced probabilities for below-normal precipitation (40%-30%-30%) are forecast for parts of western Sumatra.

Greatly enhanced probabilities for above-normal precipitation (20%-30%-50%) are forecast for the central portions of Philippines. The forecast over most of the rest of the Philippines indicates enhanced probabilities for above-normal precipitation (20%-35%-45%). Surrounding this region are weaker probabilities favoring above-normal precipitation extending over northern parts of Borneo and Malaysia and into the Celebes Sea region.

Enhanced probabilities for above-normal precipitation are forecast for the Caroline Islands.

Slightly enhanced probabilities for above-normal precipitation (25%-35%-40%) are forecast for parts of southern New Guinea.

Slightly enhanced probabilities for below-normal precipitation (40%-35%-25%) are forecast for much of the Kiribati islands.

Slightly enhanced probabilities for below-normal precipitation are forecast for much of western and southwestern Western Australia.

Slightly enhanced probabilities of below-normal temperature (40%-35%-25%) are forecast for much of the Philippines and western Indonesia, including Malaysia, Sumatra, Java, and Borneo.

Slightly enhanced probabilities of above-normal temperature (25%-35%-40%) are forecast for most of New Guinea and extending southward over western Northern Territory and eastern Western Australia.

Enhanced probabilities for above-normal temperature (20%-35%-45%) are forecast for the Solomon Islands, and extending eastward to about 150W in the tropical Pacific between 15S-15N.

Slightly enhanced probabilities of below-normal temperature (40%-35%-25%) are forecast for southwestern Western Australia, and also over a region covering parts of South Australia and New South Wales.

OBSERVED CLIMATOLOGY DATA for Aug-Sep-Oct, Sep-Oct-Nov, Oct-Nov-Dec and Nov-Dec-Jan

CLIMATOLOGICAL AVERAGE: Temperature Precipitation

TERCILE THRESHOLDS (33%-ile & 67%-ile): Temperature Precipitation

EXTREME THRESHOLDS (15%-ile & 85 %-ile): Temperature Precipitation

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