The Climate Prediction Center is soliciting
comments from August 1, 2023 through January 31, 2024 on the implementation
of the Week 2
and experimental Week 3 Global Tropics Hazards Outlook.
Here is the Survey.
GTH Outlook Map and Data
Last Updated -
GTH Outlook Discussion
Last Updated -
02/28/24 - 03/12/24
RMM observations show a westward retreat of the MJO signal over the Western Pacific earlier this month, but the MJO has since resumed its eastward propagation and has moved into phase 8 (Western Hemisphere) in RMM space. Consistent with model guidance since last week, a much weakened MJO is generally favored in the RMM forecasts, with model solutions showing the signal mostly remaining within the unit circle during the next two weeks. However, there is some question as to whether this weakening is reflective of a disorganizing MJO or the removal of the 120-day mean which is strongly skewing the MJO signal to the right in RMM space. Upper-level velocity potential anomaly and OLR forecasts suggest the latter, which depict a more coherent MJO moving forward. Anomalous lower-level westerlies forecast continue to enhance probabilities for tropical cyclone (TC) development for the southwestern Indian Ocean through early March.
It has been an active week for TCs around the globe, with 5 TCs that formed in 4 different basins. In the South Pacific, TC 15P formed east of the Cook Islands on February 15 and quickly dissipated. In the Australia region, TC Lincoln formed in the Gulf of Carpentaria on February 15 and moved inland quickly, bringing heavy rain to northwestern Australia. In the South Indian Ocean, on February 17 TC Djoungou formed east of Madagascar. It moved southwestward and became very strong before weakening and transitioning to an extratropical system. On February 18 TC Eleanor formed, also east of Madagascar. It is currently still active, meandering near Mauritius, and is currently forecast to eventually move towards Madagascar. For the latest information on TC Eleanor please refer to the Joint Typhoon Warning Center (JTWC). Finally, a rare South Atlantic TC formed southeast of Rio de Janeiro on February 18. It strengthened and was named Akara on February 19, and is currently tracking south.
Despite a relatively weak RMM signal among forecast models, other indicators of MJO activity suggest a stronger MJO than might otherwise be expected. Upper-level velocity potential anomaly forecasts portray a weak to moderate MJO taking shape during weeks 2-3, with increasing anomalous divergence aloft over Africa and into the Indian Ocean as the forecast period progresses. This results in a moderate probability (>40%) for TC activity in the southwestern Indian Ocean during weeks 2-3. Interestingly, Indian Ocean MJO (phases 2 and 3) events historically lead to decreased chances for TC formation near Australia and the Maritime Continent but guidance from both the GEFS and ECMWF suggest a higher chance for TC genesis during the forecast period across the northern Australian coast than might otherwise be indicated, possibly due to Rossby or Kelvin wave interference. The large-scale environment is expected to remain weakly favorable for TC development over the southeastern Indian Ocean during week-3, and 20% chances for TC genesis are issued for portions of the northern Australian coast.
The precipitation outlook for weeks 2 and 3 is based on potential TC activity, the anticipated state of the MJO, and a skill-weighted consensus of GEFS, CFS, Canadian, and ECMWF ensemble mean solutions. Above-normal precipitation continues for the Equatorial Eastern Pacific for both weeks, a response to the El Nino conditions, while suppressed precipitation is favored to the north and south of the El Nino-enhanced precipitation. Continued below-normal precipitation is indicated for portions of northern South America for week-2, and above-normal temperatures are likely for eastern Brazil during both weeks. Above-normal precipitation becomes more likely over the western Indian Ocean as the next MJO cycle begins during the forecast period. During week-2, above-normal temperatures are likely for the eastern U.S., much of Brazil, portions of western Australia, and much of southern Africa, while below-normal temperatures are favored for eastern China.
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.
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.
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
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.
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.).
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.
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.
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.
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.
Feedback and Questions