Tuesday, April 26, 2022

  • Revised IMD Rainfall Normals..And how the new Normals would compare this year ( 2022).
  • The New IMD All-India rainfall southwest monsoon season normal  is based on Data from 1971-2020. For the SWM Season ( June-September) is 868.6 mms. It will replace the earlier normal of  880.6 mms based on the period 1961-2010.
  •  Thus there is a decrease of 12.0 mm season and 16.8 mm in annual rainfall 2010 to 1971-2020. 
  • IMD estimate of SWM this year 2022 is 99% ..or Normal which ranges from 96%-104% of current values.
  • So 2022 expected to reach 858 mms as per changed norms. This would mean 97% of the older Normal.
  • That fit just in the Normal range 96% - 104% 
  • Normal range is quite large : 833 mms- 902 mms  (New )
  • & 845 mms -  916 mms ( old )
  •  The New All-India annual compared to earlier normal of  based on Data from 1971-2020 is 1160.1 mms. It will replace the earlier normal of  1176.9mm based on the period 1961-2010.

1 comment:

NilaY Wankawala said...

Credit Australian Government Bureau of metereology latest issued 26 04 2022

Issued 26 April 2022

The latest Climate Driver Update and Climate Model Summary are now available on the Bureau's website.

La Niña weakens, although atmospheric signal persists

The 2021–22 La Niña event continues to weaken, with oceanic indicators mostly at neutral levels. However, atmospheric indicators remain above La Niña thresholds, meaning La Niña's influence continues.

Sea surface temperatures in the tropical Pacific are cooler than average but have been at neutral levels for much of April. Beneath the surface, waters also remain slightly cooler than average. However, in the atmosphere, indicators remain at typical La Niña levels, with stronger than average trade winds in the western Pacific and decreased cloudiness across the tropical Pacific region. The Southern Oscillation Index (SOI) also continues at moderate to strong La Niña levels, although this signal is dominated by conditions at Tahiti.

Six of seven climate models surveyed by the Bureau indicate a return to neutral El Niño–Southern Oscillation (ENSO)—neither La Niña nor El Niño—during the late southern hemisphere autumn or in early winter. Only one model continues La Niña conditions through winter.

The Indian Ocean Dipole (IOD) is neutral. Outlooks for the IOD show a negative IOD developing in the coming months. While model outlooks have low accuracy at this time of year and hence some caution should be taken with IOD outlooks beyond May, there is consistency across the forecasts from all international models. A neutral IOD has little influence on Australian climate. A negative IOD increases the chances of above average winter–spring rainfall for much of Australia. It also increases the chances of warmer days and nights for northern Australia.

The Southern Annular Mode (SAM) index is currently neutral, but is expected to briefly dip to negative levels with neutral to positive levels thereafter for the coming two to three weeks. During autumn SAM typically has a weaker influence on Australian rainfall.

The Madden–Julian Oscillation (MJO) has recently become weak. Climate models indicate the MJO is likely to remain weak, having little influence on tropical weather and climate in the coming fortnight.

Climate change continues to influence Australian and global climate. Australia's climate has warmed by around 1.47 °C for the 1910–2020 period. Southern Australia has seen a reduction of 10–20% in cool season (April–October) rainfall in recent decades. There has also been a trend towards a greater proportion of rainfall from high intensity short duration rainfall events, especially across northern Australia.

More information

Media enquiries: (03) 9669 4057 media@bom.gov.au

Next update expected on 10 May 2022