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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 - 10.28.14 (Routine)


\"Global
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: 10.28.14 Valid: 10.29.14 - 11.12.14
The MJO became increasingly incoherent during the past week, based on recent observations and both the RMM and CPC velocity potential MJO indices. OLR time-longitude analyses indicate the presence of an eastward moving envelope currently propagating over the Indian Ocean. This signal, however, is experiencing destructive influence from the suppressed phase of an equatorial Rossby Wave currently propagating over the Maritime Continent. The enhanced phase of the Rossby Wave over the western Pacific is also out of phase with any MJO-like activity over the Indian Ocean.

There is considerable spread among the dynamical model MJO index forecasts. The GFS has consistently indicated increasing amplitude over the Western Hemisphere and Africa during the next two weeks, while the ECMWF forecast depicts a weak signal that favors convection over the western and central Pacific. The UKMET likewise maintains a weak signal, but favors enhanced convection over the Indian Ocean. The divergent model solutions indicate the difficulty resolving the future evolution of the weak signal currently over the Indian Ocean and the competing influence of a SST-based low frequency state favoring suppressed convection over the Maritime Continent and enhanced convection across the western Pacific. This outlook, therefore, is not based on the anticipation of an emerging subseasonal signal, favoring instead any large-scale regions where the divergent CFS and ECMWF models are consistent with each other.

Cyclone Nilofar developed over the Arabian Sea on 25 October, attaining Category-4 intensity on the Saffir-Simpson Scale. Nilofar is currently moving northward and is anticipated to turn northeastward and weaken before making landfall near the border between India and Pakistan. Tropical depression (TD-9) developed over the southern Bay of Campeche briefly on 22 October. The remnants of TD-9 intensified and became Tropical Storm Hanna on 28 October before making landfall over eastern Nicaragua. During the upcoming week, a robust late season disturbance over the eastern Pacific has a high probability of development early in the period. A second disturbance east of the Lesser Antilles has a low to moderate potential for brief development before interacting with a mid-latitude trough over the central Atlantic. Elsewhere, a disturbance well east of the Philippines has a low potential for development, and a low potential for tropical cyclogenesis also exists for a broad area of low pressure north of Madagascar.

During Week-1, enhanced convection is favored over eastern Tanzania the southwestern Indian Ocean north of Madagascar, as well as across the Arabian Sea in association with Cyclone Nilofar. Enhanced convection is also favored over the equatorial central Indian Ocean due to influence from the weak eastward moving signal. Suppressed (enhanced) convection is favored over parts of the Maritime Continent (north of New Guinea) due to Rossby Wave influence and the low frequency state. An active ITCZ favors enhanced convection south and southeast of Hawaii, while a potential tropical cyclone may bring heavy rainfall to western Mexico. The remnants of Hanna may bring localized heavy rainfall to parts of Central America.

Enhanced (suppressed) convection over the north-central Indian ocean and western Pacific (southern Maritime Continent) is anticipated to continue during Week-2, with a low potential for tropical cyclone development over the northern Indian Ocean. The CFS favors enhanced precipitation over the central Pacific to lift northward, possibly bringing above-average rainfall to Hawaii, while the ECMWF forecasts a return to suppressed rainfall across northern and eastern Brazil. A mid-latitude trough over the central Atlantic, possibly in association with the remnants of a weak tropical cyclone, is anticipated to bring enhanced convection to a broad region north of Hispaniola and south of Bermuda.

Forecasts for enhanced or suppressed convection over Africa are based on regional scale features and provided through coordination with CPC's Africa Desk.

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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