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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 - 10.02.15 (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: 10.02.15 Valid: 10.03.15 - 10.13.15
The MJO remained weak during the past few days, with most variations in tropical convection being modulated by ENSO and tropical cyclones. Specifically, Hurricane Joaquin has been meandering near the Bahamas for the last few days, and is now forecast to move north-northeastward. Two tropical cyclones developed over the West Pacific, with Tropical Storm Mujigae near the Philippines and Tropical Depression Choi-wan near Wake Island.

A Kelvin wave is moving across the central and eastern Pacific, and is likely to influence convection during the next week. The ongoing El Nino is also forecast to continue through the Northern Hemisphere winter of 2015-2016.

During the next 4 days, the threat of tropical cyclone formation is enhanced over the Central Pacifc, from about the Date Line to 150W, 10 - 20N, as well as over the East Pacific near 130W. Enhanced favorability over both regions is likely related to the ongoing El Nino and Kelvin wave forecast to move through the area. There is also a disturbance over the central Atlantic Ocean, with an 80 percent chance of formation during the next 5 days. Above average rains are likely near the forecasted paths of the tropical cyclones, and over the Central Pacific due to the ongoing El Nino.

After those 4 days, the largest threat of tropical cyclone formation shifts to southeast of Hawaii. Some models are also indicating a low to moderate threat of tropical cyclone formation near the northern Lesser Antilles. The areas of above/below median rainfall reflect the ongoing El Nino.

------------------ Previous Discussion Follows ------------------------

The ongoing, strong El Nino continues to remain the major contributor to large scale tropical convective anomalies. The Wheeler-Hendon RMM MJO index indicates no MJO signal, while the CPC Velocity Potential index features a pattern consistent with the background state.

Most dynamical models depict little to no signal over the next 2 weeks, with the GEFS being the exception. The GEFS depicts a westward moving signal over the central Pacific, moving to the western Pacific by Week-2. The signal is not related to MJO activity, and likely related to tropical cyclone activity over the central and western Pacific.

Tropical Storm Joaquin developed over the western Atlantic, and is forecast to move northward, potentially having a major impact on the CONUS form the Mid-Atlantic to the Northeast. Tropical Storm Niala formed south of Hawaii while Hurricane Marty developed near the southern coast of Mexico. Typhoon Dujuan develoepd over the west Pacific and made landfall along the east coast of Taiwan, bringing heavy rains to the island.

During Week-1, tropical cyclone formation odds are increased over the West Pacific, from about 155E to the Date Line, 10N - 20N. Over the East Pacific, tropical cyclone formation is likely near 120W, while over the Atlantic, the odds of formation are slightly enhanced near 60W. Some models have a weak signal for tropical cyclone development over the Bay of Bengal during Week-1. The climatological peak is later October through early December, and the signal is weak, so no specific hazard is depicted. The central and eastern Pacific are the areas with the highest odds of formation during Week-2.

Patterns of anomalous rainfall during the upcoming week are based on ENSO and dynamical models, which indicate above average rains over Southern India, the Central Pacific including the southernmost islands of Hawaii, and the East Pacific due to tropical cyclone activity. Below average rainfall is forecast over the Maritime Continent and the Caribbean, consistent with ENSO conditions. Some of the signal over the East Pacific is also being derived from statistical tools indicating the passage of a Kelvin Wave during Week-1. Above-average rainfall favored for parts of the East Coast and western Atlantic is related to Tropical Storm Joaquin and anomalous easterly flow/moisture.

During Week-2, below average rains are likely over the Maritime Continent and Caribbean, although there is less certainty over the Caribbean as the Kelvin wave over the East Pacific late in Week-1 could mitigate some ENSO impacts. CFS and GFS models both indicate heavy rains near Vietnam, but the European Center models do not, so the area is highlighted for above average rains, but with a lower confidence. Over the central and eastern Pacific, above average rains would be consistent with the ENSO state and forecast tropical cyclone activity.

Forecasts for Africa are done in collaboration with CPC's Africa 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 Author: CPC Web Team
Page last modified: 9-Jun-2014 3:37 PM EDT
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