Tuesday, October 4, 2016

Experimental Climate Monitoring and Prediction for Maldives – September 2016


HIGHLIGHTS

Monitored: Up to 250 mm and 200 mm rainfall was received by central and southern islands respectively at the beginning of September 2016. Thereafter dry conditions were seen throughout the Maldives. No rainfall was seen in any part of the country after the 19th of September. The cumulative rainfall of the past 365 days remains above average due to previous high rainfalls. The sea surface temperature around Maldives and Sri Lanka is up to 10C below 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 more than 200 mm rainfall in August


 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 October, the northern half of the country usually receives up to 200 mm rain while the southern half receives up to 250 mm rain. Wind is westerly. The entire country usually receives up to 200 mm rain in November with no change in the wind direction from October. Usually in December, northern islands receive up to 150 mm while central and southern islands receive up to 200 and 250 mm rain respectively. Southern islands get north easterly wind while southern islands get northerly wind.


Climatology



Monitoring

Weekly Rainfall Monitoring:


Date Rainfall
17th Sep 2016 Up to 120 mm in Lhaviyani and Baa atolls. Up to 70 mm in other northern atolls.
18th Sep 2016 Up to 30 mm in northern islands
19th Sep- 1st Oct 2016 No Rain



Monthly and Seasonal Monitoring:

In September 2016 the entire country received below average rainfall. The deficit of rainfall during this month is estimated to be around 150 mm. The cumulative rainfall in the last 365 days remains above average due to very high rainfall in July and August. Central island receives more than 250 mm rain in End-August/ Early-September but received no rainfall towards the end of the month. Similar rainfall pattern was seen in southern islands as well where up to 200 mm rainfall was received in Early-September.


Ocean State Monitoring:

Pacific Seas State Sep 15, 2016:

During mid-September 2016 the tropical Pacific SST anomaly was close to -0.5C, the weak La Niña threshold. However, not all of the atmospheric variables support weak La Niña conditions. Although the upper level winds in the tropical Pacific are somewhat suggestive of La Niña, the lower level winds remain near average. The Southern Oscillation index and the pattern of cloudiness and rainfall in the equatorial Pacific are somewhat suggestive of weak La Niña conditions, but could also be interpreted as being in the cool-neutral range. The collection of ENSO prediction models indicates SSTs hovering at levels near borderline La Niña during fall, then weakening to cool-neutral in late fall and into winter. (Text Courtesy IRI)

Indian Ocean Monitoring September 21, 2016: 

~10C below average SST was observed around the Maldives




Predictions

Weekly Rainfall Forecast:

According to IMD GFS model less than 10 mm rainfall is expected in the entire Maldives during 3rd to 7th October. There shall be up to 40 mm rain on the 8th and up to 20 mm rain on the 9th in central islands. The IRI CFS model predict no heavy rainfall events during 2nd -7th October.



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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