2022 South Asia Monsoon Outlook

The southwest monsoon impacts South Asia from June through September and is an important period for agriculture. Before we jump to the forecast, we will quickly look at some teleconnections.

Some winter sea-surface temperature teleconnections include water temperatures off northwestern Australia and the northern Arabian Sea. The warm waters off northwestern Australia are a positive correlation for rainfall across South Asia during the summer monsoon. From the following image, we can see no clear signal from water temperatures over the Arabian Sea.

Some other SST-based teleconnections include the Atlantic Multi-decadal Oscillation (AMO), Pacific Decadal Oscillation (PDO) and the Indian Ocean Dipole (IOD). As the climate models show, we are expecting a warm AMO and a slightly negative PDO which are both favorable signals for rainfall in South Asia this summer. The IOD looks to become moderately negative later in the summer going into autumn which may mean a drier period for the monsoon late in the season.

The big signal will be the current La Nina which has passed its peak and may return to neutral during summer, but some signs like the negative South Pacific Oscillation (SPO) and negative South Pacific Meridional Mode (SPMM) could result in weak La Nina conditions persisting through much of the summer.

The sea-surface temperatures charts above favor some cool waters lingering over the central equatorial Pacific through summer which should result in weak La Nina conditions persisting well into the monsoon season.

The ENSO charts from the NMME and IMME show the Nino 3.4 region staying on the cool side of normal.

Lingering La Nina conditions would favor at least normal rainfall across much of South Asia as does some of the other sea-surface temperatures-based teleconnections. The -IOD and -PDO may continue to favor several monsoon lows forming over the Bay of Bengal during the pre-monsoon, monsoon and post-monsoon. The following multi-model ensembles and several teleconnections favor good news for rainfall across South Asia during the summer.

Now that we have looked at rainfall across South Asia during the monsoon, we are looking at the Southern Oscillation Index (SOI) as a sign of when the monsoon may arrive in Kerala.

A strongly positive SOI prior to the monsoon season and an easterly QBO should favor monsoon onset in Kerala around the normal onset date of 1 June, plus or minus four days.

Now that we looked at several teleconnections below is our outlook for the South Asia monsoon season.

The expected monsoon lows in the Bay of Bengal run the risk of leading to wetter conditions than forecast across areas from Odisha and northern Andhra Pradesh to Madhya Pradesh and perhaps Gujarat into eastern Rajasthan. The dry areas shown in southern Kerala and Sri Lanka could also be wetter depending on the track of the monsoon lows. There is also the risk that Jammu and Kashmir could be drier than forecast.