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ATTENTION:
The Climate Prediction Center is soliciting
comments from August 1, 2023 through December 31, 2024 on the implementation
of the Week 2
and experimental Week 3 Global Tropics Hazards Outlook.
Here is the Survey.
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GTH Outlook Map and Data
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Last Updated -
07/16/24
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GTH Outlook Discussion
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Last Updated -
07/16/24
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Valid -
07/24/24 - 08/06/24
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A coherent wave-1 pattern has recently emerged in 200-hPa velocity potential (VP) anomalies and has shown some modest eastward propagation over the last week or so. The RMM index currently places the MJO in phase 5 (Maritime Continent) just outside the unit circle. There is quite a diversity of opinion among forecast models with regard to MJO evolution in the coming weeks. Some models, notably the GEFS favor a very weak RMM signal with little propagation, while many models including the ECMWF, BoM, and CFS models favor higher amplitudes and steady eastward movement of the enhanced convective envelope into and across the Pacific throughout the forecast period. The current strength and apparent movement of the wave-1 VP dipole would tend to favor the more bullish MJO forecasts.
One tropical cyclone (TC) formed over the last week. On July 14 TC 03W formed in the South China Sea southeast of Da Nang, Vietnam. It quickly moved ashore over the central Vietnamese coast and dissipated by the 15th.
Synoptic conditions over the Western Pacific forecast to be initially conducive for tropical cyclone (TC) genesis at the outset of week-2 but are forecast to become less favorable as the forecast period continues, with the MJO depicted as either propagating away from the Maritime Continent or weakening in amplitude. For today’s preliminary forecast a moderate risk (40% probability) of TC genesis is posted for portions of the South China Sea and Philippine Sea for week-2 and a slight risk (20% probability) for the same areas for week-3.
Meanwhile, the anticipated propagation of the MJO would tend to produce an increasingly favorable environment for TC genesis over the eastern Pacific Ocean. The ECMWF is very bullish in this regard, depicting probabilities of TC activity for the basin exceeding 60% into week-3 and beyond. Therefore, a slight risk for TC genesis is posted for portions of the Eastern Pacific basin for week-2 and a moderate risk for week-3. A slight risk for TC genesis is also posted for portions of the Caribbean and the tropical Atlantic where SSTs are very warm, and which also become more favored for TC development as the convectively enhanced phase of the MJO propagates further into the central Pacific.
The precipitation outlook for weeks 2 and 3 is based on potential TC activity, the anticipated state of El Nino and the MJO, and informed by GEFS and ECMWF ensemble mean solutions. Enhanced precipitation is favored over portions of Southeast Asia and the Maritime Continent throughout the forecast period. Increased chances for above-normal precipitation are also indicated for much of Central America for both weeks. Below-normal precipitation is favored over the equatorial Central Pacific for both weeks, potentially a result of a weakening El Nino, as well as for the southern Indian Ocean.
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
[email protected], [email protected], [email protected] and [email protected] 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
