Monday, November 7, 2016

Experimental Climate Monitoring and Prediction for Maldives – October 2016


HIGHLIGHTS

Monitored: In October, central islands received up to 120 mm above average rainfall while northern and southern islands received up to 120 mm below average rainfall. Up to 180 mm rainfall received by the central islands is the highest rainfall received in past six years in this region for this period. During the last week of October a decrease in rainfall throughout the country was visible. The sea surface temperature around Maldives and Sri Lanka is up to 0.50C above the seasonal average. 
Predictions: IRI seasonal prediction predicts 50% chance of having below average rainfall until the end of 2016. Some El Nino prediction models suggest of weak La Niña conditions as the Pacific SST anomaly is close to -0.50C. Long Range Weather prediction models simulations do not expect heavy rainfall in the next week.
Central islands received up to 180 mm rainfall in October


 Printable Version of the Full Report (PDF)


---------------------------Inside this Issue------------------------

  1. Monthly Climatology
  2. Rainfall Monitoring
    1. Daily Satellite derived Rainfall Estimates
    2. Monthly Rainfall derived from Satellite Rainfall Estimate
    3. Monthly and Seasonal Monitoring
  3. Ocean Surface Monitoring
  4. Rainfall Predictions
    1. Weekly Predictions from NOAA/NCEP
    2. Seasonal Predictions from IRI

SUMMARY

Climatology

Monthly Climatology:

In November, the whole country usually receives up to 200 mm rain. Wind is westerly. Usually in December, northern islands receive up to 150 mm while central and southern islands receive up to 200 and 250 mm rain respectively. Northern islands get north easterly wind while southern islands get northerly wind. In January northern islands receive up to 50 mm rain while central and southern islands receive up to 100mm and 250 mm rain respectively. Wind is north easterly.


Climatology



Monitoring

Weekly Rainfall Monitoring:


Date Rainfall
19th Oct 2016 Up to 100 mm in Kolhumadulu atoll. Up to 50 mm in southern atolls.
20th Oct 2016 Up to 50 mm in central and southern islands.
21st - 22nd Oct 2016 Up to 20 mm in central and southern islands.
23rd - 24th Oct 2016 Up to 20 mm in northern and central islands.
25th Oct 2016 Up to 35 mm in central islands.
26th - 28th Oct 2016 No rain.
29th Oct 2016 Up to 15 mm in northern islands. Up to 30 mm in southern islands.
30th - 31st Oct 2016 Up to 15 mm in northern island.
1st Nov 2016 Up to 35 mm in northern islands. Up to 15 mm in southern islands.
2nd Nov 2016 Up to 15 mm in northern islands.



Monthly and Seasonal Monitoring:

In October 2016 the central islands received ~120 mm rainfall above the climatological average and northern and southern islands received ~120 mm rainfall below the climatological average. In central islands the second highest recorded rainfall this year (~180 mm) was received in October. This is the highest rainfall observed in central islands during the past 6 years during this period. Central islands including Kolhumadulu atoll received up to ~450 mm rain in October while rest of the southern and the northern islands received up to ~240 mm rain.


Ocean State Monitoring:

Pacific Seas State Oct 20, 2016:

During mid-October 2016 the tropical Pacific SST anomaly was slightly cooler than -0.5C, the threshold for weak La Niña. However, not all of the atmospheric variables have been supporting weak La Niña conditions for a sufficient duration to constitute good ocean-atmospheric coupling. Although the upper level winds suggest weak La Niña, the lower level trade winds only became stronger than average in mid-September. The Southern Oscillation index and the pattern of cloudiness and rainfall do indicate weak La Niña conditions. The lack of enhanced trade winds until recently makes us hesitate to say La Niña has really begun, so our diagnosis remains ENSO-neutral. The collection of ENSO prediction models indicates SSTs near or slightly cooler than the threshold of La Niña during fall, then weakening to cool-neutral during winter. (Text Courtesy IRI)

Indian Ocean Monitoring October 26, 2016: 

~0.50C above average SST was observed around the Maldives




Predictions

Weekly Rainfall Forecast:

According to IMD GFS model up to 70 mm rainfall is expected in southern Maldives while up to 10 mm and 40 mm rainfall is expected in the central and northern islands respectively during 4th to 6th November. There shall be up to 40 mm rain on the 7th and 8th in southern islands and up to 10 mm rainfall in central islands. Up to 70 mm rainfall is expected in southern islands on 9th.No rainfall is expected in any part of the country on 10th. The IRI CFS model predicts extremely heavy rainfall events during 3rd -8th November.



Seasonal Rainfall and Temperature Prediction:

As per IRI Multi Model Probability Forecast for October to December 2016, there is a 50% chance that the rainfall shall be below average in central islands. The 3-month average temperature has a 60% likelihood to be in the above-normal tercile in southern islands during these 3 months. Temperature in northern islands shall be climatological.



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