The MJO continued to be active across the eastern Indian Ocean and Maritime Continent in the past week, with a recent pause and some weakening experienced in recent days. The Maritime Continent region is also active with a Kelvin wave analyzed coincident with the MJO, and an equatorial Rossby wave projected to shift westward across the region early this week. Other Kelvin waves are analyzed across the East Pacific and Central Africa. Key uncertainties for this week fall in regard to whether propagation of the MJO through the Maritime Continent will occur, and if El Nino related impacts will potentially re-emerge should destructive interference from the subseasonal state begin to wane. Dynamical guidance varies widely in regards to handling of the MJO with solutions tending towards a decaying signal during the next two weeks, however, some models propagate the MJO signal across the Pacific while others have a re-emerging signal across the Indian Ocean. Given the aforementioned uncertainty and the time of year, any tropical teleconnection influences on the midlatitudes are expected to be weak.
A number of low-confidence tropical cyclogenesis potential areas exist over the forecast period, despite no hazard being explicitly present on the forecast maps. Dynamical guidance has intermittently hinted at cyclogenesis during week-1 in the South China Sea that is consistent with the MJO presence, however confidence in any development is low at this time. Another area of potential tropical cyclone development exists in week-1 for the Southern Indian Ocean to the northeast of Madagascar associated with a pre-existing disturbance. This disturbance is expected to drift westward over the course of week-1 and remain weak, despite anomalously warm SSTs and ample low-level moisture. Dynamical guidance has suggested potential tropical cyclogenesis north of the Greater Antilles during the middle of week-1, with the disturbance subsequently tracking up the east coast of Florida before moving over the Southeast CONUS. Over the last 24-hours models have trended weaker with this system, with many now merely suggesting an open wave. While SSTs for the region are near 27 Celsius, upper-oceanic heat content may be marginal to support any sustained development. Despite current uncertainty with progression of the MJO during the forecast period, a signal in Phase 5 would support suppressed convection across the Tropical Atlantic. Given the generally unfavorable background state and recent dynamical model trends, no Atlantic tropical cyclogenesis hazard is currently portrayed on the map. East Pacific climatological tropical cyclone activity also increases during the month of June, while observed SSTs here remain anomalously warm off of the equator. Ensemble guidance predicts some weakness in the surface pressure field during week-2 that could subsequently materialize into a tropical cyclone, however no discrete hazard is forecast at this time. Should the MJO continue into Phase 6 the background climatic state would become more favorable for any East Pacific formation.
The precipitation outlook during Week-1 is based on CFS and ECMWF model guidance and expectations for a weakening MJO signal in Phase 5. A strong signal for above-average precipitation during week-1 is favored for: the Western Maritime Continent and Southeast Asia due to the MJO presence, portions of the Southern Indian Ocean associated with the slow-moving cyclone noted in the previous paragraph, and portions of the Central Pacific Ocean to the southeast of the Date Line where persistent anomalously warm SSTs exist. A moderate confidence region of above-normal precipitation in week-1 extends northeast of the Phillipines associated with the Meiyu front presence. For the CONUS, a high confidence region of above-average rainfall exists across northeastern Texas associated with a stationary boundary. A moderate confidence region of above-normal precipitation is forecast for the Southeastern U.S., Bahamas, and Greater Antilles for late in week-1 due to the expected presence of the tropical wave noted in the prior paragraph. A moderate confidence area of much above normal temperatures is forecast during week-1 for portions of western interior South America where maximum temperature anomalies may exceed 8 Celsius, yielding observed temperatures greater than 35 Celsius.
The week-2 precipitation outlook favors above-average precipitation across the Phillipines and West Pacific associated with the Meiyu front, and parts of the South Indian Ocean, South Pacific, and East Pacific due to the presence of anomalously warm SSTs. Below-average precipitation is favored for the western and central North Indian Ocean and western Maritime Continent in the wake of the MJO.
A moderate confidence area of much above normal temperatures is forecast for Central Brazil where a greater than 20% chance of exceeding the 95th percentile of climatological maximum temperatures is anticipated.
Forecasts over Africa are made in consultation with CPC's 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.
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.
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.