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

Last Updated - 01.23.18 (Routine)


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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
Above Average Temperatures KMZ / KML / SHP KMZ / KML / SHP
Below Average Temperatures KMZ / KML / SHP KMZ / KML / SHP

Global Tropics Hazards and Benefits Outlook Discussion

Last Updated: 01.23.18 Valid: 01.24.18 - 02.06.18
The MJO remains coherent, with both the RMM-based and CPC velocity potential based MJO indices depicting robust amplitude and eastward propagation. The enhanced convective phase of the MJO is over the Maritime Continent, constructively interfering with the La Nina base state. A large envelope of enhanced trade winds persists over the western and central Pacific, with westerly anomalies extending from the Indian Ocean to Borneo. The upper-level velocity potential anomalies continue to reflect a coherent Wave-1 pattern, with the anomalous upper-level divergence in phase with negative OLR anomalies over the Maritime Continent. Dynamical and statistical model RMM-index forecasts consistently depict a continuation of robust MJO activity over the next several weeks, with the enhanced convective phase propagating over the West Pacific by Week-2. The ECMWF depicts a slightly faster propagation of the signal, and the 30-day ECMWF run maintains an amplified signal over the East Pacific and Western Hemisphere through Weeks 3 and 4. Based on these observations and forecasts, the MJO is anticipated to play a large role in the evolution of the global tropical convective pattern, and will likely continue to influence the midlatitude response. This MJO event has teleconnected well with the North American longwave pattern, and has contributed to the warming trend across the central and eastern CONUS. A West Pacific MJO event would potentially support a pattern change during early to mid-Feburary, with increased ridging over western North America, and downstream troughing over eastern Canada and the U.S.

No new tropical cyclones formed during the past week. During Week-1, the primary region of concern for tropical cyclone development is across the south-central Indian Ocean and north of Australia. There is moderate potential for tropical cyclone formation either in the Gulf of Carpentaria or north of Western Australia, with several GFS ensemble members depicting landfall of a powerful tropical cyclone along the Kimberley Coast. The Joint Typhoon Warning Center is currently monitoring a second region over the south-central Indian Ocean for tropical cyclone development. If a tropical cyclone develops in this region, it would likely take a westward to southwestward track over open waters. During Week-2, the favored region for tropical cyclogenesis shifts eastward to the Coral Sea, with development still possible over the Gulf of Carpentaria. Should tropical cyclone development occur, the circulations may act to slow the propagation of the overall MJO envelope as depicted in the RMM index.

Forecasts for above- and below-normal precipitation were made using a consensus of bias-corrected CFS and ECMWF forecasts, as well as MJO precipitation composites for Phases 5, 6 and 7. During Week-1, an envelope of enhanced precipitation is favored from the southeastern Indian Ocean to the southwestern Pacific, including much of northern Australia. This area of enhancement is consistent with MJO activity, with potential contributions from tropical cyclones. Suppressed convection is favored across the equatorial central and eastern Indian ocean, and across the central Pacific, which is consistent with the ongoing La Nina. Dynamical model forecasts indicate areas of enhanced convection across the North Pacific, including southeastern Hawaii. Additionally, enhanced rainfall is likely across eastern Mexico, northern Central America, the Gulf of Mexico, and parts of the U.S. Gulf Coast.

During Week-2, the broad envelope of enhanced convection is favored to propagate eastward, extending from the Philippines southeastward to Fiji and American Samoa. Areas of suppressed convection are forecast surrounding this region, over the southern Indian Ocean and near the Date Line. Additionally, dynamical models favor a region of enhanced precipitation across south-central and southeastern Brazil.

During Week-1, GFS and CFS forecasts depict a persistence of much above-normal temperatures across southeastern Australia, compounding the ongoing heat wave. During Week-2, a highly amplified pattern supports a cold air outbreak across China, with potentially hazardous cold penetrating as far south as northern Vietnam, parts of Thailand, and Taiwan.

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 full Global Tropics Hazards and Benefits Outlook (GTH) is released once per week every Tuesday at 1730 UTC (1830 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 and soon will be recorded.

CPC also issues an operational update of this product every Friday by 1730 UTC to further support the NWS regions. The update only spans 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 does not extend the time horizon of the product, but rather applies 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.

Product Description

The Global Tropics Hazards and Benefits Outlook is a forecast for areas with elevated odds for above- or below-median rainfall, above- or below-normal temperatures and regions where tropical cyclogenesis is favored 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. Above(below) normal temperature forecast areas are depicted in orange and below 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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