By Sanjeev Kumar Patro
Bhubaneswar: Even as the cyclonic depression in the Bay of Bengal today crossed North Tamil Nadu – south Andhra coasts close to Chennai bringing heavy rainfall in the states like Tamil Nadu, South Andhra Pradesh, Karnataka and Kerala, the hotter Bay of Bengal will be seeing the birth of another cyclonic system in next 120 hours.
The three Indian weather prediction models are unanimous on the cyclone genesis in the Bay of Bengal in October last week, but differ on dates. While IMD-GFS and INCOIS predict the date of formation of low pressure area on October 21, the NCMRWF’s NCUM – global model predicts the date of formation of low pressure area on October 27.
GLOBAL MODELS FORECAST
All the three reputed global model weather forecasts agree on the date of low pressure formation. The global models of ECMWF, US based NCEP –GFS and Australia’s ACCESS are unanimous on the low pressure area developing over the Andaman seas, on and around October 21.
Moreover, even as all of the models agree on intensification of the LPA or say cyclone genesis, only NCEP-GFS is predicting the system intensifying into a severe cyclone.
INDIAN MODELS VS GLOBAL MODELS
A look at the model data of all the three Indian models and 3 reputed global models brings the following conclusions.
- IMD, INCOIS and NCUM-G, NCEP-GFS, ACCESS, ECMWF predicting easterly waves seeding the low pressure area in the Bay of Bengal.
- NCUM, IMD and INCOIS predict the place of formation at over south Andaman at over the southeast Andaman seas
- Australia’s ACCESS model forecasts the system taking shape over south Central Bay of Bengal.
- ECMWF model is predicting the system to form over south east Andaman seas, on and around Oct 20/21.
- NCEP-GFS predicts the formation of the LPA system over south east Andaman seas, on and around October 20/21.
WEATHER INFERENCES
An analysis of the all the weather models available at hand reveals the following weather inferences.
- Easterly waves triggering the cyclone genesis in Bay of Bengal after October 20.
- Of the 6 reputed models, only one - NCUM-G – predicts the date of formation on October 26/27.
- In contrast, all five models predict the date of LPA formation on Oct 20/21.
- However, when it comes to place of formation, the model predictions are almost unanimous.
- IMD-GFS, INCOIS, reputed Indian and global model of NCMRWF (NCUM), ECMWF and NCEP-GFS models see the low pressure area coming up over Andaman seas.
- But Australia’s ACCESS bet on the south central Bay of Bengal..
- Moreover, the differences over date of formation are attributed to date of propagation of strong easterly wave over the Andaman seas and Bay of Bengal.
WEATHER BIG OBSERVATIONS
After a careful analysis of the whole range of reputed weather models at the hand, it can be safely concluded that cyclone genesis is for sure over the Bay of Bengal on October 20 afterwards. But the haze is still over the exact date of formation. But majority models bet on October 20/21.
However, when it comes to intensification, GFS is the only model to predict intense intensification up to the severe cyclone level.
But IMD-GFS, INCOIS, ECMWF and ACCESS prediction didn’t indicate to such an intense intensification, when all the parameters that were relied upon to derive the intensity is within 7-days period.
MEGA WEATHER CONCLUSION
As today is October 17, and the date of formation is only 5 days apart, model analysis shows a most probable cyclone genesis over Bay of Bengal, and the system taking an aim at Odisha.
The models of IMD, INCOIS, ACCESS, and ECMWF very clearly predict the cross over place as Odisha. IMD and INCOIS models predict the wind speed at around 68-80kmph.
The BOTTOMLINE is it’s time for the State Disaster Management Authority (SDMA), and Revenue and Disaster Management Department brace themselves up for the possible cyclonic storm
