The MJO remained weak during the past seven days. The RMM-based MJO index indicated some strengthening near the Maritime Continent, but the CPC velocity potential index did not indicate strengthening or organization. The upper-level velocity potential pattern depicts a wave-2 structure, with enhanced convection over the Indian Ocean and over the Central Pacific, with subsidence from the Americas to Africa and over the Maritime Continent. Mid-latitude influence is also evident in 850-hpa and 200-hpa wind anomaly plots. OLR anomalies indicate some Equatorial Rossby wave activity over the Indian Ocean.
Dynamical model forecasts of the MJO indicate the development of a more coherent signal, with eastward propagation across the Maritime Continent to the Central Pacific. That implies destructive interference with the ongoing El Nino early in the outlook period, shifting toward potential constructive interference late in the outlook period. The destructive interference yields lower confidence for the early portions of the outlook.
No tropical cyclones developed during the past week. During Week-1, the passage of the Equatorial Rossby wave over the Indian Ocean is likely to enhance odds for tropical cyclone formation across the South Indian Ocean. Later in the week, odds for torpical cyclone formation increase of the South Pacific, where the odds of formation there remain enhanced into Week-2. Some model outputs also indicate a slight increase in tropical cyclone formation odds over the Central Indian Ocean, from about 60E to 80E.
Above-median precipitation is forecast across the the western and central Pacific Ocean, as well as portions of the Maritime Continent, although the Maritime Continent portion of the outlook is less certain for reasons mentioned above. The strongest signals for below-median precipitation are across the western North Pacific near the Philippines and across portions of Brazil, consistent with the ongoing El Nino. A pause in the Australian monsoon is also indicated for the outlook period. Some models indicate the potential for a cold air outbreak over Southeast Asia later in Week-1 and into early Week-2.
During Week-2, the strongest signals are all consistent with the ongoing El Nino, as the MJO is likely to be coming into phase with the ongoing El Nino. Above-median precipitation is likely over the Central Pacific, while below median precipitation is likely over the Maritime Continent and northern South America. Some model solutions are also indicating the potential for a cold air outbreak over East and Southeast Asia, with the odds of temperatures falling into the lowest 10 percentile being 4 times as likely as average. The cold air is expected to moderate quickly.
Forecasts over Africa are made in consultation with CPCs international desk, and can represent local-scale conditions in addition to global-scale variability.
Product Release Information
The Global Tropics Hazards and Benefits Outlook is released once per week every Tuesday at 1530 UTC (1630 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.
The Global Tropics Hazards and Benefits Outlook is a forecast for areas with elevated odds for above- or below-median rainfall and regions where tropical cyclogenesis is favorable or unfavorable 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. 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.