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GTH Outlook Map and Data
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Last Updated -
07/08/25
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GTH Outlook Discussion
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Last Updated -
07/08/25
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Valid -
07/16/25 - 07/29/25
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The MJO continues to be disorganized with other tropical modes providing the bulk of variability throughout the global tropics. Upper-level velocity potential anomalies continue to show a wave-1 pattern heading into early July, however there is little to no sign of eastward propagation characteristic of a reorganizing MJO, with this pattern remaining stationary but growing stronger. With this low-frequency response established , some model guidance favors a strengthening of the stationary envelope of enhanced convection over the Maritime Continent and West Pacific, and suppressed convection favored to persist over the central and eastern Pacific and the western Indian Ocean during July. Even with the growing low frequency footprint, model ensembles also generally indicate a potential reemergence of MJO during the forecast period. With both of these drivers potentially at play, the large-scale environment looks to be less favorable for tropical cyclogenesis in the eastern Pacific and Atlantic basins during the next several weeks. However, the same factors tend to favor tropical cyclone development over the Western Pacific.
Three tropical cyclones (TCs) formed during the last week, two in the Western Pacific and one in the Atlantic. On July 1 the Joint Typhoon Warning Center (JTWC) issued advisories for TD04W, which formed east of the Mariana Islands, and was named Mun after further development the following day. Mun drifted generally northward towards Japan, and is anticipated to become a post tropical system. On July 4, TC Danas formed in the South China Sea and quickly intensified to become the first typhoon of the 2025 Western Pacific season. On July 6 Danas made landfall on the western coast of Taiwan and moved north along the coast, then moving back over the ocean near Taipei. TC Danas is still active, and is anticipated to make landfall again along the Chinese coast south of Shanghai in the next day or so. For the latest information on TCs Mun and Danas please refer to the JTWC. Also on July 4, TC Chantal formed in the Atlantic Ocean east of the Florida Peninsula. Chantal strengthened to a tropical storm the following day and moved generally northward, making landfall east of Charleston, SC on July 6, resulting in heavy rainfall and flooding over portions of the Mid-Atlantic region.
Dynamical model RMM-based forecasts indicate a strengthening MJO signal, with solutions generally moving through phases 5-7. Along with a potentially revived MJO, the low-frequency enhancement of divergence aloft over the Western Pacific creates a very favorable environment for TC genesis. This is well-indicated by model guidance, which show high probabilities of TC activity throughout the forecast period. Therefore, a high risk (>60% chance) of TC genesis is posted for week-2 over the Western Pacific east of Luzon, with moderate (40-60%) to slight (20-40%) risks extending into the South China Sea. The moderate and slight risks extend into week-3, although the high risk is removed due to increased divergence of model solutions with regard to MJO positioning. A slight risk of TC genesis is also posted for the northern Gulf Coast of the U.S. for week-2, where weak troughing and surface convergence over warm Gulf waters has the potential to spin up a closed low.
The precipitation outlook for weeks 2 and 3 is based on potential TC activity, the anticipated low frequency response and the MJO, and informed by GEFS, CFS, Canadian, and ECMWF ensemble mean solutions. For hazardous weather conditions in your area during the coming two-week period, 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. Forecasts made 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
