|
|
GTH Outlook Map and Data
|
Last Updated -
10/08/24
|
|
|
|
|
|
GTH Outlook Discussion
|
Last Updated -
10/08/24
|
Valid -
10/16/24 - 10/29/24
|
The MJO continues to be a significant player in the global tropics. The RMM index currently places the enhanced convective envelope over the Indian Ocean. Dynamical model MJO forecasts depict eastward propagation of the intraseasonal signal into the Maritime Continent and Western Pacific during the next several weeks, with a more suppressed convective pattern developing across North America in the wake of the MJO. Tropical cyclone (TC) activity is favored to be greatest over the Indian Ocean and Western Pacific during weeks 2 and 3. The suppressed phase of the MJO is depicted over the Americas during this period which would tend to inhibit TC formation, however potential destructive Kelvin wave interference leads to lingering chances for TC activity on either side of Central America throughout the forecast period.
It was another busy week for TC activity, with 5 storms forming globally. On Sep 30, TC Ancha formed in the southwest Indian Ocean east of Madagascar. It remained disorganized and dissipated quickly. On Oct 1, TD 11 formed off the southern coast of Mexico. It remained offshore and was quickly broken up by strong shear but nonetheless brought heavy rainfall to portions of Mexico. On Oct 2, TC Leslie formed near the Cape Verde Islands. Leslie reached hurricane intensity but has since weakened to a tropical storm. It is still active and is expected to move northward into the open Atlantic according to the National Hurricane Center (NHC). On Oct 5, TC Milton formed in the Bay of Campeche. On Oct 7 Milton underwent very rapid intensification, reaching category 5 strength. Currently a category 4 hurricane, Milton is forecast to move over the Florida Peninsula during the overnight hours of Oct 9/10, posing significant hazards for the region. For more details on the status of Hurricane Milton please refer to the NHC. Finally, on Oct 6 TC 21W formed southeast of Guam. It is currently near tropical storm strength and the Joint Typhoon Warning Center (JTWC) expects the system to move northward into the open Pacific in the coming days.
During weeks 2 and 3 dynamical model RMM forecasts favor the MJO transiting across the Maritime Continent and into the Western Pacific. This places the highest chances for TC formation during the forecast period in the Eastern Hemisphere. During week-2 a slight chance (20-40%) of TC development is highlighted for the Arabian Sea , the southern Bay of Bengal (BoB), and the western Pacific from the Philippines to roughly 160 E. A moderate risk for TC genesis is posted for the northern BoB due to favorable placement of the MJO. Additionally, models depict a persistent westerly wind burst over the equatorial western Indian Ocean during weeks 1 and 2 which has the potential to spin up a TC on either side of the equator, therefore a slight chance for TC formation is highlighted for the southwestern Indian Ocean as well for week-2. During week-3 as the MJO continues to move eastward the moderate risk for TC development shifts from the BoB to the South China Sea and the western Pacific. In the Western Hemisphere chances for TC development are relatively modest after a very active period. Models depict a Kelvin wave moving over the Americas sometime during the next few weeks interfering with the suppressed phase of the MJO and resulting in a lingering slight chance for TC genesis on either side of Central America throughout the forecast period.
The precipitation outlook for weeks 2 and 3 is based on potential TC activity, the anticipated state of ENSO and the MJO, and informed by GEFS, CFS, Canadian, and ECMWF ensemble mean solutions. Much of southeast Asia and the Maritime Continent are favored for above-normal precipitation for both weeks due to the favorable position of the MJO. Below-normal precipitation is favored near the Date Line, a product of emerging La Nina conditions. Below-normal precipitation continues to persist for northern South America, continuing a long trend that has led to significant impacts in the Amazon Basin. Above-normal temperatures are indicated for portions of the central U.S. during week-2.
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.
|
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.
|
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.
|
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.
|
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.
|
Product Resources
|
|
Feedback and Questions
|
|
www.nws.noaa.gov
