September Month India Weather Outlook: Above Normal Rains Likely in Central And South India.

Indian Monsoon

September is officially the last month of the Indian Southwest Monsoon. It is the time when the Monsoon starts withdrawing from northwest India. The rains start reducing from north to south, withdrawing gradually from the entire country before 20th October. In this month temperature starts shooting up, cloud cover gets reduced. Thunderstorms start developing more frequently due to high temperatures and atmospheric instability.

Monsoon Rains(Pan India) 1st June to 31st August:

Normal: 700.7 mm

Actual: 743.8 mm

Departure from normal: +6.15%

Monsoon 2022 has performed well by looking at numbers, but at ground reality. Monsoon rainfall distribution is uneven. U.P and Bihar have received deficit rains, whereas Rajashtan, Gujarat, M.P, and Telangana are some states that got excess rains. We will cover this report in the next article.

Monsoon Rains June 1st to August 31st

September Month Weather Outlook:

We will check the following five parameters to conclude.

1) MJO

2) SST

3) IOD

4) Nino 3.4

5) Somali Jet

1) MJO: It is an east-to-west moving big cloud across the equator. bringing dry and wet phases with it. Currently, MJO is in phase 2 and will soon move to phase 3. The ECMWF and GEFS forecast indicates MJO to remain in phases 3-7. Phases 3-7 are favorable for Indian Monsoon. It usually results in normal to above normal rains. This parameter is positive for good rainfall

GEFS MJO Forecast

2) SST: Sea surface temperature is also a crucial factor. Warmer the sea more intense and frequent circulations get developed. 0.5 to 1C above normal temperatures likely in a north bay of Bengal. This indicates good chances of circulations getting developed into stronger systems. This parameter is positive for good rainfall.

3) IOD: Indian ocean dipole is differential heating of the Indian ocean. It has 3 phases, positive, negative, and neutral. Positive is good for monsoon, whereas negative is bad for monsoon. Currently, a negative Indian ocean dipole is seen. The last week recorded a -0.8C value. The global models forecast shows that the value will go down to -1C for September. This parameter is neutral to negative for good rainfall.

September IOD Forecast

4) Nino 3.4: Enso is the differential heating of the eastern tropical pacific ocean. There are 3 phases el-Nino, neutral, and la-Nina. La Nina is good for the Indian monsoon. el Nino is the villain of the Indian monsoon. Neutral has not much effect on the Monsoon. currently, la nina conditions are prevailing. Nino 3.4 is expected to reach the value of -0.8C in September. This parameter is positive for good rainfall.

Nino 3.4 Global Models Forecast

5) Somali Jet: It is a low-level jet seen during monsoon season. It attains its peak in July. The stronger the jet, the more intense and widespread rainfall is observed. It brings abundant moisture from the Indian ocean. It is forecasted to remain above normal in the south Arabian sea and below normal in the north Arabian sea. This parameter is neutral for good rainfall.

September Rainfall Forecast: Above-normal rains are likely in central and south India. Normal rains are likely in northwest and east & northeast India. 

Delhi: Normal rains.

Mumbai: Above normal

Kolkata: Normal

Chennai: Normal to above normal

Bengaluru: Normal to above normal

September Temperature Forecast: Above normal temperatures are likely in east & northeast India and the western Himalayan region. Normal temperature in central and south India. Rajasthan & parts of Gujarat, west coast are likely to record below-normal temperatures.

Delhi: Normal

Mumbai: Normal

Kolkata: Above Normal

Chennai: Normal

Bengaluru: Normal to below normal