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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 - 07.28.15 (Routine)

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 Tropics Hazards and Benefits Outlook Discussion

Last Updated: 07.28.15 Valid: 07.29.15 - 08.12.15
The MJO weakened significantly during the past week, with the tropical circulation pattern not reflective of influence from the MJO. Both the CPC Velocity Potential based index and the Wheeler-Hendon, RMM based index indicate no MJO activity, with both indices indicating westward movement during the past week. The upper-level velocity potential pattern exhibits a wavenumber-3 pattern. The low-frequency, El Nino state continues to be reflected in the circulation pattern, with enhanced divergence over the eastern Pacific, and generally enhanced subsidence over the Atlantic and western Pacific. Low-level and upper-level wind anomalies continue to reflect the low-frequency state as well, with low-level westerly anomalies across much of the western and central eqautorial Pacific Ocean. Some vascillations in the South Asian Monsoon are also evident in time lapse images.

Dynamical model forecasts continue to depict a significant spread in potential outcomes related to the MJO. Most of the global models indicate a westward moving signal, with strengthening over the West Pacific. That signal is likely due to an equatorial Rossby wave currently indicated in some analyses near the Date Line, along with tropical cyclone activity likely to occur over the West Pacific.

Tropical depression 8E formed over the East Pacific on Monday, July 27. The forecast track from the National Hurricane Center takes the depression toward Hawaii, with longer range model guidance indicating a cluster of tracks mostly south of Hawaii. High significant wave heights near Hawaii are likley later this week, but impacts from precipitaiton and wind are too uncertain at this time to depict on the outlook map. Additional tropical cyclogenesis, in the wake of TD8E, is likely later in Week-1 over the East Pacific, as well as over the West Pacific between 145E and 170E. A stalled front across the southeast U.S. could serve as a focal point for tropical cyclone development, later in Week-1, although confidence in the actual development of a tropical depression is low. During Week-2, the favored areas for tropical cyclogensis move eastward over the East Pacific (100W - 120W) and Westward over the West Pacific (125E-150E).

During Week-1, above average rainfall is likely across northern India and southern Pakistan, associated with a pulse in the South Asian Monsoon. The low-frequency state supports above average rains near the Date Line and over the east Pacific, with below average rainfall likely from southern India to the Philippines and Maritime Continent, as well as over the Caribbean, Mexico, and extremem southern Texas.

During Week-2, the low-frequencey state and potential tropical cyclones are likely to dominate the pattern of tropical convection. Below average rains are likely from South Asia to the Maritime Continent, as well as over the South China Sea, with above average rains from the just west of the Date Line to the East Pacific. Dry conditions are likely to prevail from Central America to the Lesser Antilles.

Forecasts for enhanced or suppressed rainfall across Africa are provided in collaboration with CPC's Africa Desk and are based on MJO composites 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 Author: CPC Web Team
Page last modified: 9-Jun-2014 3:37 PM EDT
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