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HOME > Climate & Weather Linkage > Global Tropics Benefits/Hazards

Last Updated - 03.20.18 (Routine)

GIS Ready Formats
Tropical Cyclone Formation KMZ / KML / SHP KMZ / KML / SHP
Upper Tercile Precipitation KMZ / KML / SHP KMZ / KML / SHP
Lower Tercile Precipitation KMZ / KML / SHP KMZ / KML / SHP
Above Average Temperatures KMZ / KML / SHP KMZ / KML / SHP
Below Average Temperatures KMZ / KML / SHP KMZ / KML / SHP

Global Tropics Hazards and Benefits Outlook Discussion

Last Updated: 03.20.18 Valid: 03.21.18 - 04.03.18
The MJO signal was weak during the past 7 days, and was destructively interfering with a westward-moving Equatorial Rossby Wave (ERW). The latest observation places the center of the enhanced convection inside the unit circle in RMM phase space. With regard to predicted phase, dynamical model guidance shows a wide array of possible solutions, emphasizing much uncertainty. The NCEP GEFS model predicts the most likely area for the MJO signal over the next two weeks will be over the vicinity of the Maritime Continent, though several ensemble members favor the emergence of a weak subseasonal signal outside the unit circle in phase 6 (Western Pacific). The ECMWF solution predicts a very weak signal over the eastern Indian Ocean and Maritime Continent region (phases 3 to 5) during Week-1, followed by increasing spread among ensemble members, with many coming out of the unit circle over the Western Pacific and the Western Hemisphere (phases 7,8). The CFS model indicates a weak intraseasonal signal during Week-1, which then amplifies significantly in the Western Pacific (phase 7), and propagates eastward into phase 8 (Western Hemisphere) during Week-2. The Constructed Analog statistical tool anticipates a slowly progressive, weakening MJO signal across the Indian Ocean and Maritime Continent during the two-week forecast period. In general, the subseasonal signal is expected to have a limited impact in phases 5 and 6 (eastern Maritime Continent/Western Pacific) during Week-1, and phases 6 and 7 (Western Pacific) during Week-2.

There were two tropical cyclones (TCs) in progress at the time of this writing. TC 14S (Eliakim), now a tropical storm near Madagascar, is forecast to track slowly southeastward out over the open waters of the South Indian Ocean. The second system, TC 15S (Marcus) is currently a strong cyclone off the Kimberley Coast of western Australia, with maximum sustained winds of 110 knots. The Joint Typhoon Warning Center (JTWC) predicts Marcus will continue to head west before recurving southward well off the West Coast of Australia during the next 5 days. For the upcoming Week-1 forecast period, three TC's are expected to develop, all in the Southern Hemisphere. One region of potential TC development is the South Indian Ocean (10S-20S/80E-100E, moderate confidence); a second is over the Gulf of Carpentaria and Arafura Sea just north of Australia (5S-15S/125E-145E, high confidence); and the third region is over the Coral Sea northeast of Australia (10S-20S/155E-175E, moderate confidence). Another area of potential TC development, though only with low confidence, is about 15 degrees northeast of Papua New Guinea. This area is also being monitored with the Taiwan Typhoon Tracker tool, with most scenarios recurving any potential TC northeast of the Philippines.

Rainfall forecasts for Weeks 1 and 2 are based primarily on consensus areas between ECMWF, GFS, and CFS model precipitation, anticipated locations of TCs, and the most likely location of the subseasonal signal as noted earlier. During Week-1, a mid-level trough digging southeastward towards the Hawaiian archipelago is forecast to bring a moderate risk of heavy rainfall to the Islands. Elsewhere, an expected southwesterly subtropical flow is likely to bring heavy rain (3-7 inches) to central and southern portions of California, with the Sierras anticipated to receive 24-48 inches of new snow above about 8000 feet in elevation. During Week-2, the various model precipitation forecasts agree only on a few areas for anomalous precipitation, with the primary MJO-related signal for above-average rainfall confined to the Maritime Continent/Western Pacific region. Areas where below-average rainfall are anticipated include the central South Indian Ocean (in the wake of the forecast TC during Week-1), and along the Equator from about 165E to 145W (low frequency La Nina dry signal).

Forecasts over Africa are made in consultation with the CPC international desk and can represent local scale conditions in addition to global scale variability.

Product Release Information

The full Global Tropics Hazards and Benefits 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 and soon will be recorded.

CPC also issues an operational update of this product every Friday by 1730 UTC to further support the NWS regions. The update only spans the release period from June 1 through November 30 and a region from 120E to the Prime Meridian in longitude and from the equator to 40N in latitude. The update does not extend the time horizon of the product, but rather applies for the remaining 4 days of the previous Week-1 time period and Days 5-11 from the previous Week-2 period. This page will depict both the original and updated outlook maps as well short text outlining the forecast rationale for any changes.

Product Description

The Global Tropics Hazards and Benefits Outlook is a forecast for areas with elevated odds for above- or below-median rainfall, above- or below-normal temperatures and regions where tropical cyclogenesis is favored for the upcoming Week-1 and Week-2 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 yellow respectively. Above(below) normal temperature forecast areas are depicted in orange and below respectively. Favored areas for tropical development are shown in red. Two measures of confidence are indicated, high (solid) and moderate (hatched) and are currently subjective in nature and not based on an objective system. Work towards a probabilistic format of the product and so an objective measure of confidence is ongoing. 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.

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 created subjectively based on a number of forecast tools, many of which are objective. The final depiction is an assessment of these forecast tools based on a number of factors to create the final product. Work is ongoing to create an objective consolidation of some of the available forecast tools to serve as a first guess for the forecaster. Forecast tools include MJO composites, empirical and dynamical based MJO, ERW and KW forecasts, and raw dynamical model guidance from a number of modeling systems. Tropical cyclone areas are based on MJO composites and statistical and dynamical tropical cyclone forecasts as well as raw model forecast guidance.

Product Purpose

The product supports the NOAA mission in three primary ways:

  1. 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
  2. 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)
  3. Support various sectors of the U.S. economy (finance, energy, agriculture, water resource management) that have foreign interests.

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.

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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