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GTH Outlook Map and Data
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Last Updated -
07/15/25
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GTH Outlook Discussion
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Last Updated -
07/15/25
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Valid -
07/23/25 - 08/05/25
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A stable pattern is observed in the global upper-level velocity potential field, indicative of low frequency variability dominating the pattern across the global tropics. Anomalous upper-level divergence (enhanced convection) is noted across portions of the Indian Ocean, Maritime Continent, and the Western and Central Pacific. Conversely, anomalous upper-level convergence (suppressed convection) is indicated across the Eastern Pacific, Americas, Atlantic, and extending over portions of Europe and Africa. This convective pattern has not changed much compared to the prior week and has resulted in the RMM-based Madden Julian Oscillation (MJO) index meandering over the Maritime Continent (phase-4). The GEFS and ECMWF predict a robust MJO event emerging from the main convective envelope over the Maritime Continent during the next week. The ECMWF is faster compared to the GEFS, with its ensemble mean depicting eastward propagation of the MJO into the Western Hemisphere around the start of August.
The enhanced convective state across much of the Eastern Hemisphere has led to increased tropical cyclone (TC) activity across the Western North Pacific. Several TCs developed in the past week, including Tropical Storm Nari (7/11), Tropical Depression 07W (7/12), and Tropical Storm 08W (7/15). Nari peaked as a strong tropical strom as it tracked to the southeast of Japan. The other systems were weaker, with 07W tracking across the East China Sea, making landfall near Kyushu, Japan and 08W predicted to remain a weak tropical storm as it moves along the coast of eastern Japan. The basin is predicted to remain active with additional TC formations likely over the next few weeks. A greater than 60 percent chance for TC development is highlighted in the week-2 outlook from the northern portion of the South China Sea to about 145 deg E due to a continued favorable environment aloft and continued strong signals in the GEFS and ECMWF guidance. During week-3, chances decrease to 40-60 percent and become oriented more east-northeastward as the MJO becomes more active across the Pacific. Also of note is the increased potential for out of season TC development across the southeast Indian Ocean during the next week (Invest 90S).
The enhanced convergence aloft has resulted in a less favorable environment aloft for TC formation across the Eastern North Pacific and North Atlantic basins. The exception is across the U.S. northern Gulf Coast where a disturbance along a quasi-stationary front may acquire tropical characteristics as it potentially tracks across very warm water. The National Hurricane Center (NHC) notes a 40 percent chance of TC development during the next week. The ongoing lull in activity is expected to continue through the next 2 weeks but activity may begin to increase again during week-3 as the MJO propagates across the Pacific, with the faster ECMWF favoring a stronger signal. Therefore, a 20-40 percent chance for TC formation is highlighted across the Eastern North Pacific for week-3. No areas of potential TC formation are indicated across the Atlantic at this time. However, if the MJO moves into a more favorable position, and coincident with increasing climatology across the Main Development Region, it is possible TC activity may begin to tick upwards in early to mid-August across the Atlantic.
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 week-2, high probabilities (greater than 80 percent) for above-normal rainfall are forecast across the Western North Pacific coincident with predicted TC activity. Conversely, below-normal rainfall is predicted across much of the Equatorial Pacific and Indian Oceans. Odds for below-normal rainfall are enhanced during week-2 across Central America and adjacent waters, but become more uncertain by week-3. Ridging forecast to build across the continental U.S. favors above-normal temperatures with some concerns for extreme heat across central and eastern parts of the U.S.
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
