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GTH Outlook Map and Data
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Last Updated -
06/09/26
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GTH Outlook Discussion
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Last Updated -
06/09/26
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Valid -
06/17/26 - 06/30/26
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The Madden-Julian Oscillation (MJO) remained active during the past few weeks, with a strong projection on both the CPC velocity potential based MJO index, and the RMM-based MJO index. A clear propagation from the Indian Ocean to the East Pacific was observed in the wind fields and OLR anomalies since mid-May, with the amplitude of the signal increasing markedly as the intraseasonal signal constructively interfered with the evolving low-frequency state over the Pacific. As SSTs continue to warm over the equatorial Pacific and drive a pronounced atmospheric response, the low frequency base state is favored to become the increasingly dominant player in the evolution of the global tropical convective pattern. Over the next several weeks, the MJO signal is favored to weaken due to influence from other modes. An equatorial Rossby wave is forecast to propagate over the West Pacific during Week-1 and Week-2, potentially generating a low-level westerly wind burst that would be out of phase with an eastward propagating MJO envelope. Additionally, the MJO signal or Kelvin wave activity moving out of the Pacific across the Western Hemisphere would experience increasingly destructive interference from the base state. Dynamical model MJO index forecasts generally depict a weakening signal, with very little indication that the enhanced phase will return to the Indian Ocean basin. However, by Week-3, many dynamical model ensemble members show the signal quickly returning to the Pacific, likely tied to Kelvin wave activity, which has been pronounced over the past few months. Based on these forecasts, the low-frequency base state is favored to contribute most to the evolution of the tropical convective pattern, while the intraseasonal signal may alternately weaken the atmospheric response during Week-2 and then strengthen it during Week-3.
Three tropical cyclones formed in the past week, all over the East Pacific basin. Tropical Storm Amanda formed on 3 June just west of 100W, which is the furthest west a tropical cyclone has formed in the basin this early in the season. Two additional tropical storms developed on 8 June: TS Boris, which formed just off of Mexico's southern coast, and TS Cristina, which developed near Nicaragua. Enhanced shear in the atmosphere limited the intensification of these systems, and currently only TS Cristina is active. Heavy rains are forecast across central America as the system meanders just off the coast. potentially moving inland by the end of Week-1. Its remnants may emerge over the Gulf of Mexico, but redevelopment is not currently anticipated. During Week-2, destructive interference between the intraseasonal signal and the low-frequency state may reduce the potential for tropical cyclogenesis over the East Pacific. The basin may become increasingly favorable for development towards the end of Week-2, and dynamical model ensemble members depict a potential for closed low formation during the period. Therefore, a 20-percent chance of formation is maintained during Week-2. Conditions are favored to become highly favorable for TC development during Week-3, with a greater than 60 percent chance of formation posted over the East Pacific. Elsewhere, tropical cyclogenesis is not favored in association with the Rossby Wave over the West Pacific due to strong upper-level winds in the vicinity. Dynamical models indicate a potential for development over the Northwest Pacific near or east of Guam during Week-2, extending northeast of the Philippines during Week-3.
Forecasts for above- and below-average precipitation are based on historical composites of warm ENSO events and Pacific MJO events for Week-3, and a skill weighted consensus of CFS, GEFS, and ECMWF dynamical model guidance. A pronounced wet signal over the central and eastern Pacific is tied to the evolving low-frequency state, as is the suppressed convective signal over the Caribbean, which may exacerbate developing drought conditions across Puerto Rico and the US Virgin Islands. Suppressed convection is also favored to persist over the South Pacific, including American Samoa. An enhanced ITCZ over the northeastern Pacific may provide opportunities for tropical cyclogenesis, especially during Week-3. Across the Eastern Hemisphere, Kelvin wave activity may bring briefly enhanced convection to the eastern Indian Ocean during Week-2, while an enhanced Meiyu Front is forecast to bring wet weather to southern China and Japan. Suppressed convection is favored to persist over the equatorial Maritime Continent in both Week-2 and Week-3. Weak monsoon activity over South Asia may be accompanied by hot temperatures.
For hazardous weather conditions in your area during the next two weeks, please refer to your local NWS office, the Medium Range Hazards Forecast from the Weather Prediction Center (WPC), and the CPC Week-2 Hazards Outlook. Forecasts issued over Africa are made in coordination with the International Desk at CPC.
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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
