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Weeks 2-3 Global Tropics Hazards Outlook (GTH)
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ATTENTION:
The Climate Prediction Center is soliciting comments from September 13, 2022 through March 31, 2023 on the implementation of the experimental Weeks 2 and 3 Global Tropics Hazards Outlook.
Here is the Survey.
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Outlook Map and Data
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Last Updated -
01/24/23
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Outlook Discussion
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Last Updated -
01/24/23
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Valid -
02/01/23 - 02/14/23
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The amplitude of the Madden-Julian Oscillation (MJO) RMM-based index increased substantially over the past few days, indicating that the enhanced phase of the MJO is located over the Indian Ocean. This recent amplification was well forecasted by the suite of dynamical model guidance as discussed in the previous outlook last week. As the intraseasonal signal increasingly interferes constructively with the ongoing La Niña base state, widespread enhanced convection has developed across the Maritime Continent. Over the equatorial Pacific, the trade wind regime has strengthened and expanded, and the previously extended East Asian jet has retracted, reducing the extent of Pacific moisture flow over western North America. The MJO has been active over the past several months, and dynamical model MJO index forecasts indicate a continuation of this pattern. Following a stationary period of enhancement over the Indian Ocean during Week-1, the GEFS depicts robust MJO activity crossing the Maritime Continent during Week-2, and entering the Pacific basin during Week-3. The ECMWF shows a similar evolution, albeit with a weaker progression across the Maritime Continent that may be due to aliasing with the low frequency base state that is removed from the analysis. Many GEFS and ECMWF ensemble members depict a strong Pacific MJO event. While previous MJO events have not succeeded in producing a substantial low-level westerly wind burst along the Equator over the West Pacific, the West Pacific Warm Pool has grown considerably, and a strong MJO event has the potential to initiate a strong downwelling oceanic Kelvin wave that could erode the ongoing La Niña. Therefore, both La Niña and the MJO are favored to strongly influence the evolution of the global tropical convective anomalies, which teleconnects well into the northern hemisphere midlatitude pattern this time of year. Indian Ocean and Maritime Continent MJO events are associated with downstream pattern changes favoring increased ridging and warmer temperatures across eastern North America, which is generally consistent with dynamical model forecasts for the Week-3 period. The anticipated height anomaly pattern across North America during the upcoming two weeks is also largely consistent with the cold ENSO response.
During the past week, a pair of tropical cyclones formed over the eastern Coral Sea. Tropical Storm Irene developed on January 18, strengthening to near hurricane intensity as it tracked southeastward to the east of New Caledonia. On January 20, Tropical Depression 10 formed just west of New Caledonia, but quickly dissipated in an unfavorable regime. Elsewhere, Tropical Storm Cheneso, which initially formed prior to last week’s outlook period on January 17, made landfall over northern Madagascar, bringing substantial flooding impacts. With an active MJO favored to progress from the Indian Ocean to the West Pacific over the next three weeks, the areas of potential tropical cyclone formation are also expected to progress gradually eastward. During Week-2, tropical cyclogenesis is possible over the southwestern Indian Ocean in the vicinity of the Cocos Islands, or north of Australia’s Kimberley Coast. While climatology does not favor much tropical cyclone activity over the northern Indian Ocean, both the GEFS and ECMWF favor tropical cyclogenesis near southern India or Sri Lanka during Week-2, meriting a 20-percent probability for formation.
Forecasts for above- and below-median precipitation are based on a skill-weighted consensus of operational dynamical model guidance, with an anticipated continuation of La Niña conditions and a MJO event propagating from the Maritime Continent to the West Pacific. While the forecasted MJO event is depicted as stronger than the previous event that moved through the West Pacific during late December and early January, dynamical models do not show a robust breakdown in the trade winds over the West Pacific. Therefore, enhanced precipitation due to the MJO will likely be more pronounced to the north and south of the Equator over the Pacific. While cold air outbreaks over the contiguous United States are likely during Week-2, a strong temperature gradient is favored to set up close to the Gulf Coast, and there is uncertainty about how far south the cold air penetrates into regions with subtropical and tropical agriculture. Elsewhere, dynamical models favor increased chances for above-average temperatures across portions of Brazil, which could have a negative impact on agriculture.
For hazardous weather concerns in your area during the next two weeks, please refer to your local NWS office, the Medium Range Hazards Forecast for the Weather Prediction Center (WPC), and CPC Week-2 Hazards Outlook. Forecasts 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 webinar) open to all interested parties in which the latest conditions in the Tropics
and the just released outlook and associated impacts are discussed. There is an opportunity to ask
questions after the briefing and the briefings are available at the Live Briefing
Archive.
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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
