The Madden-Julian Oscillation (MJO) propagated eastward from the Maritime Continent to the Pacific Ocean during mid-January with enhanced (suppressed) convection over the central Pacific (Maritime Continent). However, the coherent Wave-1 spatial pattern in the 200-hPa Velocity Potential anomaly field recently evolved into a Wave-2 pattern as other modes of variability began to exert their influence. Constructive interference between a Kelvin and Rossby wave is resulting in a secondary area of enhanced convection across Africa and the western Indian Ocean. Dynamical model solutions are in good agreement that the amplitude of the MJO RMM index decreases during Week-1. A more stationary pattern of anomalous convection is forecast to develop during Week-2 with enhanced (suppressed) convection remaining across the equatorial Pacific (Maritime Continent). Therefore, the MJO is expected to provide less influence on global tropical rainfall by Week-2.
The MJO likely contributed to the development of a couple of tropical cyclones (TCs) during early to mid-January. Tropical Claudia tracked near the Kimberley Coast of Australia on January 12 and 13 before dissipating as it continued its westward track. Tropical Cyclone Tino tracked near Vanua Levu of the Fiji Islands on January 17 and 18. The current state of the MJO along with predicted enhanced convection during the next two weeks elevates chances of TC development in the South Pacific and West Pacific. Moderate confidence for TC formation covers Weeks 1 and 2 in the same spatial extent given uncertainty on when development occurs. A tropical cyclone is likely to form within the next 24 hours across the South Indian Ocean, to the east of Madagascar, with a subsequent track poleward.
The precipitation outlook during the next two weeks is based largely on the model consensus among the CFS, ECMWF, and GFS models. During Week-1, the predicted tropical cyclone in the Southwest Indian Ocean along with the ongoing constructive interference between a Kelvin and Rossby wave is likely to result in above-average rainfall across eastern Tanzania, northern Mozambique, northern Madagascar, and parts of the southwest Indian Ocean. Below-average rainfall is expected to the south of this wet area. Below-average rainfall is likely across the eastern half of the Maritime Continent during Week-1, in part due to the suppressed phase of the MJO. To the south of the dry area, the Northern Terriorty and parts of Queensland are likely to receive above-average rainfall. The deterministic GFS model indicates local amounts exceeding 200 mm within the Week-1 wet area across the Northern Territory and Queensland. Above-average rainfall is likely at the Date Line which may help to initiate one or two tropical cyclones north and south of the equator. Above-average rainfall is also likely across parts of Brazil and from the western Gulf of Mexico north to the south-central United States during Week-1. Both of these wet areas are due to the mid-latitude circulation pattern interacting with enhanced subtropical moisture.
During Week-2, below-average rainfall is expected to persist for much of the Maritime Continent while above-average rainfall remains centered near the Date Line. This area of enhanced convection is forecast to extend east into the subtropics of the east Pacific and North America. Above-average rainfall is expected to shift into Bolivia and Paraguay by Week-2. Forecast confidence is lowest across the western Indian Ocean and Africa due to conflicting signals and modes of subseasonal variability. In general, a drying trend is expected from Week-1 to Week-2 across Mozambique and Madagascar. Forecasts over Africa are made in consultation with CPCs international desk, and can represent local-scale conditions in addition to global-scale variability.
Following a break from excessive heat in Australia, the GFS and CFS models indicate a return of much above-average temperatures during the next two weeks. By Week-2, much above-average temperatures are forecast to expand and include much of South Australia, Victoria, New South Wales, and southern Queensland. The 0Z ECMWF reforecast tool indicates that daily maximum temperatures have near a 60 percent chance of exceeding the 85th percentile of the climatological distribution in these areas at the end of January into the beginning of February.
Product Release Information
The full Global Tropics Hazards and Benefits Outlook (GTH) is released once per week every Tuesday at 1730 UTC (1830 UTC when on standard time) including U.S. federal holidays. At the time of product release, there is a live briefing (available via webinar) open to all interested parties in which the latest conditions in the Tropics and the just released outlook and associated impacts are discussed. There is an opportunity to ask questions after the briefing and the briefings are available at the Live Briefing Archive and soon will be recorded.
CPC also issues an operational update of this product every Friday by 1730 UTC to further support the NWS regions. The update only spans the release period from June 1 through November 30 and a region from 120E to the Prime Meridian in longitude and from the equator to 40N in latitude. The update does not extend the time horizon of the product, but rather applies for the remaining 4 days of the previous Week-1 time period and Days 5-11 from the previous Week-2 period. This page will depict both the original and updated outlook maps as well short text outlining the forecast rationale for any changes.
The Global Tropics Hazards and Benefits Outlook is a forecast for areas with elevated odds for above- or below-median rainfall, above- or below-normal temperatures and regions where tropical cyclogenesis is favored for the upcoming Week-1 and Week-2 time periods. The rainfall outlook is for precipitation integrated over a week and targets broad-scale patterns, not local conditions as they will be highly variable. Above(below) median rainfall forecast areas are depicted in green and yellow respectively. Above(below) normal temperature forecast areas are depicted in orange and below respectively. Favored areas for tropical development are shown in red. Two measures of confidence are indicated, high (solid) and moderate (hatched) and are currently subjective in nature and not based on an objective system. Work towards a probabilistic format of the product and so an objective measure of confidence is ongoing. The weekly verification period ranges from 00 UTC Wednesday to 00 UTC the following Wednesday.
Along with the product graphic, a written text outlook discussion is also included at release time. The narrative provides a review of the past week across the global Tropics, a description of the current climate-weather situation, the factors and reasoning behind the depicted outlook and notes on any other issues the user should be aware of. The discussion discusses the impacts in the Tropics as well as potential impacts in the Extratropics when relevant.
Product Physical Basis
The product synthesizes information and expert analysis related to climate variability across multiple time scales and from various sources, including operational climate monitoring products. The physical basis for the outlooks include
El Nino-Southern Oscillation (ENSO) , the
Madden-Julian Oscillation (MJO), strength and variations of the monsoon systems, other coherent subseasonal tropical variability such as atmospheric Kelvin waves (KW), Equatorial Rossby waves (ERW), African easterly waves, as well as interactions with the extratropical circulation (i.e. high latitude blocking, low-latitude frontal activity, etc.).
Product Forecast Tools
The outlook maps are currently created subjectively based on a number of forecast tools, many of which are objective. The final depiction is an assessment of these forecast tools based on a number of factors to create the final product. Work is ongoing to create an objective consolidation of some of the available forecast tools to serve as a first guess for the forecaster. Forecast tools include MJO composites, empirical and dynamical based MJO, ERW and KW forecasts, and raw dynamical model guidance from a number of modeling systems. Tropical cyclone areas are based on MJO composites and statistical and dynamical tropical cyclone forecasts as well as raw model forecast guidance.
The product supports the NOAA mission in three primary ways:
- Assess and forecast important changes in the distribution of tropical convection (i.e., potential circulation changes across the Pacific and North America sectors) and communicate this information to NWS forecasters
- Provide advance notice of potential hazards related to climate, weather and hydrological events across the global tropics (including tropical cyclone risks for several NWS regions)
- Support various sectors of the U.S. economy (finance, energy, agriculture, water resource management) that have foreign interests.
The product is created through collaboration with other NOAA centers, [the National Hurricane Center (NHC) and the Central Pacific Hurricane Center (CPHC)], the Department of Defense [The Joint Typhoon Warning Center (JTWC) and the Naval Postgraduate School (NPS)], the Australian Bureau of Meteorology, Taiwan Central Weather Bureau, the State University of New York at Albany (SUNY) and the Center for Climate and Satellites (CICS), among other collaborators.
Product Users and Applications
Known users include U.S. government agencies such as NOAA [National Weather Service (NWS), River Forecast Centers (RFCs), the National Marine Fisheries Service (NMFS), the Department of the Interior (U.S. Forest Service), aid organizations (U.S. and international Red Cross, USAID), domestic and global private sector interests (financial, energy, water resource management and agricultural sectors), international weather services and various media meteorologists.
Some special applications of the product in the past include extended range predictions to support Haiti earthquake and Deepwater Horizon oil spill relief efforts as well as support for the Dynamics of the MJO (DYNAMO) scientific field campaign held from October 2011 through March 2012.