El Nino Watched! 60% of El Nino development during fall

A few of the international weather agency has released the “El Nino” prediction during coming fall and winter.

Following is the summary of NOAA CPC report on 9 August 2018:

ENSO Alert System Status: El Niño Watch

Synopsis:  There is ~60% chance of El Niño in the Northern Hemisphere fall 2018 (September-November), increasing to ~70% during winter 2018-19.



Report from JMA on 10 August 2018:

  • ENSO-neutral conditions persisted in July.
  • It is likely that ENSO-neutral conditions will persist in boreal summer (70%).
  • It is more likely (60%) that El Niño conditions will develop in boreal autumn than that ENSO-neutral conditions will persist until boreal autumn (40%).



WMO Report on June 2018:

Sea surface temperatures in the east-central tropical Pacific as well as most of the overlying atmospheric indicators suggest that ENSO-neutral conditions are prevailing; that is, neither El Niño nor La Niña. Most dynamical and statistical forecast models suggest a continuation of the neutral conditions into the third quarter of 2018. Many models further indicate this period to be marked by a gradual warming of the tropical Pacific, eventually reaching a possible weak El Niño level by the fourth quarter of the year. However, such long-lead ENSO forecasts have substantial uncertainty, mainly related to the fact that forecasts going through the March-June period have lower confidence than those made in the second half of the year. National Meteorological and Hydrological Services will continue to closely monitor changes in the state of ENSO over the coming months.



BOM Report on 31 July 2018:

The El Niño–Southern Oscillation (ENSO) remains neutral. While the central Pacific Ocean has cooled very slightly in the past fortnight, more than half of international climate models predict warming to recommence in the coming weeks, and El Niño likely to develop in spring. Therefore, the Bureau’s ENSO Outlook remains at El Niño WATCH. El Niño WATCH means there is approximately a 50% chance of El Niño forming in 2018; double the normal chance.

Oceanic ENSO indicators remain neutral. The surface of the tropical Pacific Ocean has cooled slightly in the past fortnight but remains warmer than average. Likewise, the water below the surface of the central and eastern tropical Pacific has also cooled recently, but remains warmer than average. Atmospheric indicators such as the trade winds and the Southern Oscillation Index (SOI), remain neutral.

Most international climate models surveyed by the Bureau indicate warming of the tropical Pacific is likely to recommence in the coming weeks. Five of eight models indicate El Niño levels will be reached in the southern hemisphere spring, while a sixth model reaches El Niño levels in December.

During El Niño, winter-spring rainfall in eastern Australian is typically below average while daytime temperatures are typically warmer than average in the south.

The Indian Ocean Dipole (IOD) remains neutral. Three of six international climate models indicate a positive IOD event may develop, with a fourth model close to meeting thresholds. A positive IOD event typically reduces winter–spring rainfall in central and southern Australia, and can exacerbate any El Niño driven rainfall deficiencies.