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HOME > Climate & Weather Linkage > Global Tropics Benefits/Hazards

Beginning June 6, 2014, CPC will be issuing an operational update of this product every Friday by 1 PM ET to further support the NWS regions. The update will only span 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 will not extend the time horizon of the product, but rather apply 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.

Last Updated - 11.27.15 (Update)

GIS Ready Formats
Tropical Cyclone Formation KMZ / KML / SHP KMZ / KML / SHP
Upper Tercile Precipitation KMZ / KML / SHP KMZ / KML / SHP
Lower Tercile Precipitation KMZ / KML / SHP KMZ / KML / SHP

Global Tropical Hazards/Benefits Assessment

Global Tropics Hazards and Benefits Outlook Discussion

Updated discussion
Last Updated: 11.27.15 Valid: 11.28.15 - 12.08.15
The MJO remains weak, although the RMM based index shows some amplitude over the Indian Ocean. Convection over that region is weaker than it was a couple of weeks ago, but the low-level winds are likely keeping that index anomalously elevated. El Nino is likely to be the dominant mode of variability in the tropical convective pattern, with some impact from an Equatorial Rossby Wave and Kelvin wave near the Date Line.

Given the interacting modes of variability near the Date Line, tropical cyclone formation is likely over the South Pacific, west of American Samoa. For days 5 through 10, tropical cyclone formation odds are slightly enhanced over the northern Pacific, near the Date Line, although signals there are weaker. The GEFS is indicating a low threat of tropical cyclone formation near the Philippines, late in the second week of the outlook.

El Nino is likely to dominate the patterns of anomalous tropical rainfall. The outlook shapes for above and below average precipitation have not changed much from the previous outlook.

-------------- Previous discussion follows -------------

The MJO signal continued to be weak. The RMM based index continues to show amplitude greater than 1, but the CPC Velocity Potential based index shows no signal. The upper-level velocity potential pattern is becoming more aligned with the background El Nino, while showing weak signatures of Kelvin Wave and Eqautorial Rossby Wave (ERW) activity. Enhanaced convection during the past week was centered over the central Pacific, with a second center of action over the western Indian Ocean. Some of the convection near and east of the Date Line is associated with the ERW.

Model forecasts of the MJO latch onto the Kelvin waves and bring some convection eastward across the Indian Ocean, before reducing in amplitude, although others continue a signal across the Maritime Continent. Solutions that continue a signal across the Maritime Continent are not favored, as that would deststructively interfere with the ongoing El Nino. Models also have a difficult time with propagating ERWs, so that mode is accounted for in the final outlook by extending above average rainfall west of the Date Line in Week-1 and decreasing the covereage of below average rains over the Coral Sea region in Week-2.

Tropical Storm Rick and Tropical Storm Sandra developed over the East Pacific. Tropical storm Rick was short lived, while Tropical Storm Sandra is likely to make landfall in southern Mexico. Tropical Storm Annabelle developed over the Southern Indian Ocean, is forecast to mouth southward, and is not a threat to major land masses. During the next week, tropical cyclone formation odds are increased over the South Pacific and the Bay of Bengal, with the confidence of formation over the Bay of Bengal lower than the South Pacific. During Week-2, tropical cyclone formation odds remain enhanced over the South Pacific, and increase slightly over the northwest Pacific, although confidence in those two areas is moderate, at best.

Increased odds for above average rains spance the central Pacific and include some portions of the South Pacific, along the climatological South Pacific Convergence Zone. Below average rains are likely over the Western North Pacific, just south of Hawaii, and over central Brazil, all influenced by the ongoing El Nino. During Week-2, El Nino is likely to be the dominant climatological feature, with enhanced convection likely over the central Pacific and near the coasts of Ecuador and Colombia. Below average rains are likely over the Maritime Continent and Brazil.

Forecasts for Africa are done in collaboration with CPC's International Desk and based on model forecast guidance and regional scale anomaly features.

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.

Product Description

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.

Product Purpose

The product supports the NOAA mission in three primary ways:

  1. 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
  2. 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)
  3. Support various sectors of the U.S. economy (finance, energy, agriculture, water resource management) that have foreign interests.

Product Partners

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.

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Page last modified: 21-Oct-2015 7:52 AM EDT
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