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GTH Outlook Map and Data
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Last Updated -
10/28/25
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GTH Outlook Discussion
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Last Updated -
10/28/25
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Valid -
11/05/25 - 11/18/25
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The Madden-Julian Oscillation (MJO) strengthened during mid to late October and recently propagated from the Indian Ocean to the Maritime Continent. Constructive interference between the MJO and the ongoing La Nina led to enhanced convection across the western Maritime Continent by the final week of October. The 200-hPa velocity potential anomaly observations depict a well-defined MJO with a dipole of strong anomalous upper-level divergence (convergence) centered over the western Maritime Continent (western Africa). The anomalous upper-level divergence is at its greatest magnitude since August. The RMM index is currently shifting into phase 5 (eastern Maritime Continent). According to the GEFS and ECENS, large ensemble spread exists with the RMM index by the first week of November. This rapid increase in model spread is likely related to the MJO beginning to destructively interfere with La Nina. Despite the favored weakening of the MJO in the coming weeks, the continued subseasonal activity is expected to be an influence on anomalous rainfall across the global tropics and tropical cyclone (TC) development during early to mid-November.
From October 22 to 28, two Tropical Cyclones (TCs) formed: Sonia in the East Pacific on the 25th and Montha in the Bay of Bengal on the 26th. TC Sonia was short-lived and relatively weak. On October 28th, TC Montha (maximum sustained wind of 45 knots) is making landfall to the north of Chennai, India. The Joint Typhoon Warning Center is currently monitoring an area for TC genesis in the Arabian Sea. Powerful Category-5 Hurricane Melissa, nearing landfall in Jamaica on the morning of October 28th, formed in the Caribbean Sea back on October 21. Please refer to the National Hurricane Center for the latest updates and forecasts on Hurricane Melissa.
The MJO favors TC development across the West Pacific during the next two weeks. Model agreement is excellent and consistent that a TC forms to the east of the Philippines either just prior to or at the beginning of week-2 (November 5) with a subsequent track either over Luzon or the central Philippines. A greater than 40 percent chance of TC development is designated for the West Pacific from November 5-11 with at least one TC likely to form during this 7-day time period. During this same time, there is also a 20 to 40 percent chance of TC development across the southeastern Indian Ocean, consistent with the MJO and model guidance. By week 3 (November 12-18), a 20-40 percent chance of TC development is maintained for the West Pacific including the South China Sea which is largely based on MJO composites (phases 5, 6, and 7). For the Atlantic basin, any TC development during November typically occurs in the Caribbean Sea. Following Melissa, this region should be quiet through the start of November. However, with an increased chance of Kelvin waves emerging from the MJO overspreading the Pacific and both the GEFS and ECENS favoring above-average rainfall, at least a 20 percent chance of TC development is forecast for weeks 2 and 3, valid November 5-18. Timing is highly uncertain but the GEFS is keying on week-2 with nearly a quarter of its 0z/Oct 28 ensemble members depicting TC genesis during that time period.
The precipitation outlook for week 2 (November 5-11) and week 3 (November 12-18) is based on the historical skill weighted blend of the GEFS, CFS, and ECMWF, favored areas for TC genesis/track, MJO precipitation composites (phases 5, 6, and 7) and La Nina influences. Overall the eastern Maritime Continent, portions of the West and South Pacific, Central America, and western Caribbean are likely to be wetter-than-average during early to mid-November, while below-average rainfall is most likely across the Horn of Africa and Indian Ocean. Rainfall probabilities are lower than 50 percent across the central and eastern equatorial Pacific due to offsetting signals from the MJO and La Nina. Based on the GEFS and ECENS weeklies, precipitation anomalies are forecast to be at or slightly above-average for Jamaica and eastern Cuba during the two-week period following Melissa.
The MJO would favor above-normal temperatures expanding throughout North America by the second week of November. For hazardous weather conditions in the United States during the next two weeks, please refer to your local NWS office, the Medium Range Hazards Forecast produced by the Weather Prediction Center, and the CPC Week-2 Hazards Outlook.
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Product Release Information
The Global Tropics Hazards 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 Google Meet) open to all stakeholders where the latest conditions and the newly
released outlook are shared with the opportunity to ask questions. Folks that are interested in learning more or attending these briefings should contact
Jon.Gottschalck@noaa.gov, Scott.Handel@noaa.gov, Adam.Allgood@noaa.gov and Nicholas.Novella@noaa.gov for the required information. Each weekly outlook and GTH release briefing is
Archived and available on the website.
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Product Description
The Global Tropics Hazards Outlook is a probabilistic forecast for areas with elevated probabilities for above- or below-median rainfall, above- or below-normal
temperatures and regions where tropical cyclogenesis is favored for the upcoming Week-2 and Week-3 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 brown respectively. Above (below) normal temperature forecast areas are depicted in orange and blue respectively. Favored areas for tropical
development are shown in red. Three probability intervals are indicated for precipitation and temperature which are set at 50, 65, and 80%, while the probability
intervals for tropical cyclone development are set at 20, 40, and 60%. 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.
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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.).
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Product Forecast Tools
The outlook maps are currently based on a number of forecast tools, many of which are objective and serve as an objective first guess. The final depiction is an
assessment of these objective forecast tools augmented by the forecaster when based on additional forecast information when appropriate to create the final product.
Forecast tools include MJO composites, empirical and dynamical based MJO, ERW and KW forecasts, and bias-corrected dynamical model guidance from a number of modeling systems.
Tropical cyclone areas are based on MJO composites and statistical and dynamical tropical cyclone forecast guidance products as well as raw model forecast guidance.
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Product Purpose
The product supports the NOAA mission in three primary ways:
- 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
- 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)
- Support various sectors of the U.S. economy (finance, energy, agriculture, water resource management) that have foreign interests.
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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.
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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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Product Resources
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Feedback and Questions
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www.nws.noaa.gov
