Real Time Forecast

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Latest Verification

File NameDate & Time
Verification_MISO.ppt September 29 2014 09:27:23. hrs
Verification_spatial.ppt September 29 2014 09:19:49. hrs
Verification_anim_Aug.ppt September 29 2014 09:11:39. hrs
Verification_anim_Jul.ppt September 09 2014 10:40:58. hrs
Verification_anim_May.ppt August 13 2014 09:26:08. hrs
Verification_anim_Jun.ppt August 13 2014 09:26:05. hrs


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Archieval of Real Time Forecast

File NameDate & Time

Archieval of Forecast Verification

File NameDate & Time
Verification_20140725.ppt July 26 2014 06:54:09. hrs
Verification_20140720.ppt July 21 2014 07:37:17. hrs
Verification_20140715.ppt July 16 2014 10:58:52. hrs
Verification_20140710.ppt July 11 2014 11:28:24. hrs
Verification_20140705.ppt July 06 2014 08:37:28. hrs
Verification_20140630.ppt July 01 2014 11:22:20. hrs
Verification_20140625.ppt June 26 2014 10:27:58. hrs
Verification_20140620.ppt June 21 2014 08:12:02. hrs
Verification_20140615.ppt June 16 2014 14:37:46. hrs
FV_2013_Spatial_June_July.ppt September 10 2013 11:00:28. hrs
FV_2013_Spatial_August_September.ppt September 10 2013 11:00:28. hrs


Monsoon Onset Over Kerala

The beginning of monsoon season is marked by its onset over Kerala coast which is associated with lot of changes in the large-scale dynamical parameters as well as local moisture parameters. Prediction of monsoon onset over Kerala (MOK) is very much essential due to its socio-economical impact. Operationally, IMD has been declaring MOK subjectively based on the rainfall over Kerala, the value of outgoing long wave radiation (OLR) as well as the strength and vertical extent of the lower tropospheric zonal wind. In this report, emphasis is given to devise a criterion from circulation and rainfall in the dynamical model for the prediction of MOK.

For this, we define two indices – one from rainfall over Kerala (ROK) and another based on the strength of low level jet (LLJ). ROK is defined as the rainfall area-averaged over 74°-78°E and 8°-12°N; whereas LLJ is defined as the zonal wind at 850 hPa averaged over 55°-75°E and 5°-12°N.

Onset is defined on day 't' if ROK > 5 mm/day and LLJ > 8m/s and also if ROK and LLJ are either more than those at day 't-1' for consecutive 5 days or when the average value of ROK and LLJ for these 5 days exceed 1.5 times their value at t-1.

Conditions are relaxed in those cases when the MOK date is either obtained after 15 June or no MOK is obtained from the above mentioned criteria. The criteria is then checked for only three consecutive days and also  the cut-off value for the average value of the indices for 5 days is made 1.2 times the original value, instead of 1.5 times. For this relaxed criteria, ROK > 2.5 mm/day and LLJ > 4 m/s at day t.

The above-mentioned criteria is checked for each ensemble member and MOK is obtained for all of them. The mean day of all MOK is given as the MOK from the model. Since the long term mean date of  MOK is around 1st June with a standard deviation of ~8 days [Ananthakrishnan and Soman, 1988], the forecasts starting from16th May initial condition have been utilized for defining the date of MOK.