September Last Week Hold Any Cyclone Genesis Threat to Odisha, Andhra Pradesh , West Bengal?

By Sanjeev Kumar Patro

Bhubaneswar: STORMY days ahead for Odisha? The dynamic oceanic conditions don’t hint at normal days in the last week of September and first week of October.

Though strong westerlies are inducing cyclone genesis in the South China Sea, near Phillipines, the strong Madden Julian Oscillation (MJO) and persistence of Rossby wave till October 5, along with higher Sea Surface Temperature (SST) of around 28 degC in Andaman seas and central Bay of Bengal et al, apparently, roll out a red carpet for cyclone genesis in the south east Bay of Bengal during the last week of September or early October. 

Moreover, the Tropical Cyclone Heat Potential (TCHP), essential for intensification, in the east and southeast Bay of Bengal is remaining high at around 90-110 kjcm2.

CYCLONE GENESIS POSSIBLE?

Tropical monitoring by the models hint at high probability of cyclone genesis in the Bay of Bengal sometime in between September 25 and October 5.  Both the Global Forecast System (GFS) and Climate Forecast System (CFS) of NOAA's (National Oceanic and Atmospheric Administration) MJO velocity potential at 12 km height above mean sea level forecast indicate possible cyclone genesis over southeast or central Bay of Bengal in the last week of September. (view the main image).

The ECMWF model also predicts around 30-40 percent probability of cyclone genesis in the Bay of Bengal in September last week. 

INDIAN MODEL FORECASTS

While the National Centre for Medium Range Weather Forecast (NCMRWF) predict cyclone genesis over north Bay of Bengal on and around September 24, the GFS model of Indian Metrological Organsiation (IMD) doesn’t agree with NCMRWF’s NCUM model forecast. 

IMD GFS predict persistence of strong westerlies over south Bay of Bengal and Andaman seas from September 21onwards. The model has a prediction for a cyclonic circulation over Andhra Pradesh and Odisha on and around September 27, based on today’s conditions.

The Indian National Centre for Oceanic Information Services (INCOIS) model agrees with the NCUM model of NCMRWF about formation of a cyclonic circulation in north Bay of Bengal on and around September 23.

But, INCOIS indicate presence of the conducive conditions like higher SST, high TCHP for cyclone genesis, in case tropical disturbances cross over to south east Bay of Bengal from South China Sea. 

The BOTTOMLINE, therefore, is the haze will clear out in the next 96 hours, when the Indian Met models roll out their latest predictions based on the oceanic conditions in both Bay of Bengal and Southe China Sea.