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GTH Outlook Map and Data
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Last Updated -
07/01/25
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GTH Outlook Discussion
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Last Updated -
07/01/25
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Valid -
07/09/25 - 07/22/25
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The MJO continues to be disorganized with other tropical modes of variability continuing to prevail throughout the global tropics. Although upper-level velocity potential anomaly observations reveal more of a wave-1 pattern taking shape during late June, there is little indication of eastward propagation of the enhanced and suppressed divergence envelopes, with the pattern being more reflective of low frequency variability dominating. The lack of coherent subseasonal activity is likewise supported by RMM observations, which have shown the MJO signal meandering over phases 4 and 5 at a weak amplitude during the 2nd half of June. Looking ahead, RMM forecasts generally do not depict a meaningful MJO signal during the next few weeks, with many ensemble means and their respective members generally confined within the RMM unit circle. One exception is the GEFS, which shows the mean signal gaining amplitude over the Maritime Continent and Western Pacific at the longer leads. Notably, the GEFS heavily favors the development of an envelope of enhanced westerlies aloft from the central equatorial Pacific into the Indian Ocean along the equator, with the other models beginning to follow suit with this anomalous feature. Such a pattern would project well with phase 5 and 6 MJO events in RMM space, however, it is unclear whether this is true MJO activity reemerging or the low frequency response growing stronger with the upper-level velocity potential pattern favored to remain stationary throughout much of July. Regardless of any renewed MJO activity, this shift in the large-scale circulation being advertised is significant, as such an environment would become much less favorable for additional tropical cyclogenesis in the western Hemisphere during the next several weeks. Conversely, the persistence of enhanced divergence aloft favored from the western Indian Ocean to the central Pacific, with enhanced upper-level easterlies focused near 120E would support elevated chances for Tropical Cyclone (TC) development in the western Pacific, following a sluggish start of the 2025 season.
During the past seven days, two TCs developed in the western Hemisphere, and one in the eastern Hemisphere. As a short-lived and poorly structured system, TC Barry formed in the Bay of Campeche on 6/28 and quickly tracked into eastern Mexico bringing locally heavy rainfall and an elevated risk of flooding and mudslides while dissipating on 6/30. In the eastern Pacific, TC Flossie formed on 6/29 to the south of Mexico and steadily intensified where it is currently a category 2 strength Hurricane. The National Hurricane Center (NHC) expects Flossies to continue strengthening and peak as a category 3 system during the next day or so before rapidly weakening under the influence of cooler waters and dry air environment as it approaches the tip of Baja California. Despite this weakening, its track near the Gulf of California looks to initiate a gulf surge event and bring added tropical moisture into the Desert Southwest favorable for thunderstorm activity and gusty winds over this part of the U.S during the next few days. In the western Pacific, a short-lived tropical cyclone (TD03W) formed in the South China sea on 6/25 but quickly dissipated after making landfall in China.
For week-1, the NHC is eyeing an area in the eastern Gulf of America and western Atlantic where surface low formation is possible associated with a frontal boundary stalling over the region later this week. This low could gain tropical characteristics and there are 30% chances for development. On the heels of TC Flossie, the NHC expects another area of low pressure to develop to the south of Mexico where there are 40% chances of TC formation during the next seven days. Beyond this time, the environment in the eastern Pacific looks to become less favorable for development, however, another Kelvin wave passage is favored to encroach the basin where probabilistic guidance shows a regeneration of signals to the south of Mexico. Therefore, 20% chances for TC development are posted for week-2 from approximately 105W to 125W where shearing is favored to be more minimal. In the Atlantic basin, no TC areas are posted for week-2 given a lack of support in the tools. By the middle of July, the emergence of strong upper-level westerlies and convergence aloft is favored to take hold over the tropical Americas and the Atlantic to suppress formation potential. While additional development is certainly possible with an increasingly active climatology for July, there is not enough confidence to post any TC areas in the eastern Pacific and Atlantic basins for week-3 based on the latest extended range probabilistic guidance and the large-scale environment favored.
In contrast to the western Hemisphere, the western Pacific appears poised for additional TC development during the next few weeks. There is good agreement in the GEFS and ECMWF favoring strong anomalous lower-level westerlies along an axis from the South China Sea extending to the north of the Marianas, consistent with a reverse oriented monsoonal trough persisting across the basin. With enhanced divergence aloft favored to strengthen by the middle of July, high chances (>60%) for TC development are posted, with a broader area of moderate (40-60%) and slight chances (20-40%) issued for week-2 associated with the trough feature. Based on continued elevated signals in the probabilistic tools, 40% chances for development are posted for week-3, with coverage expanding a bit further southward in the Philippine Sea with the monsoonal trough expected to flatten some later in July.
Given the uncertainties associated with renewed subseasonal activity later in July, the precipitation outlook heavily relies on a historical skill weighted blend of GEFS, ECMWF, and CFSv2 dynamical model ensemble guidance, anticipated TC tracks, with consideration of the strengthening low frequency response. Tied to amplified 500-hPa ridging in the extratropics, above-normal temperatures with possible extreme heat conditions are favored over parts of eastern Europe, western Asia, as well as over parts of the western U.S. during week-2. Enhanced subtropical ridging over the Caribbean also may bring above-normal temperatures protruding into the southern tier of the CONUS with below normal precipitation possibly leading to drought development over parts of Puerto Rico. For hazardous weather concerns 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
