Monday, July 27, 2015

Experimental Climate Monitoring and Prediction for Maldives – July 2015

HIGHLIGHTS

There was heavy rainfall from 10th- 18th July up to 80 mm/day rainfall across the Maldives. The rainfall this July was the highest in the past 5 years in the northern islands. Still the cumulative deficit of rainfall for the last nine months remained at 30% of expected rainfall. There is a strong El Nino in place with the Eastern Equatorial Pacific Sea Surfaces warmed up as expected. That shall last for six months and as is typical. The sea around Maldives and Sri Lanka is about 1 degree Celsius higher than the average. There is a gradient in sea surface temperatures between the warmer Arabian Sea and neutral seas near Indonesia as is typical with an Indian Ocean Dipole. The implications for Maldives varies between the Northern, Central and Southern Islands when it comes to rainfall (see separate post on this) but there shall be consistent warmer than usual temperatures for the next six months.

Observed monthly rainfall in and around the Maldives in June 2015


 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:

High precipitation is usually observed in Northern Maldives in June and gradually decreases from north to south of Maldives (about 400 mm in northern islands and about 200 mm in southern islands). In July, August and September the rainfall decreases down to about 150 mm in northern islands and about 200 mm in central and southern islands. Wind direction is usually south-westerly in March and in April northern islands receive south-easterly wind while southern islands receive easterly wind. Strong easterly wind is usually observed in May and in June only northern islands get strong easterly wind. In July, August September the entire country usually do not receive strong wind.


Climatology



Monitoring

Weekly Monitoring:

During 7th – 9th July it did not rain much in Maldives. Thereafter until 18th of July up to 80- 90 mm rainfall was observed in the entire Maldives except on the 12th where no rainfall was observed. Once again no rainfall was observed on 19th and 20th. Then On the 21st light (up to 15 mm) rainfall was observed in northern and north central islands of Maldives.



Monthly and Seasonal Monitoring:

In northern islands, the highest rainfall received this year (of 100 mm) was observed in July. This amount is the highest rainfall received in the month July in the last 5 years. Not much rainfall was observed in the central islands at the start of July but the rainfall increased steadily in the 2nd and 3rd weeks of July. Although some high rainfall events were observed in southern islands there is a decreasing trend in rainfall since April 2015 in these islands. The rainfall received is about 30% less than the expected amount in central islands which is high compared to that of northern or southern islands.


Ocean State Monitoring:

Pacific Seas State July 16, 2015:

During late June through mid-July 2015 the SST was at a moderate El Niño level. All atmospheric variables support the El Niño pattern, including weakened trade winds and excess rainfall in the east-central tropical Pacific. The consensus of ENSO prediction models indicate continuation of moderate, and likely becoming strong, El Niño conditions during the July-September 2015 season in progress. Further strengthening between summer and fall is likely, with the event lasting into early 2016.

Indian Ocean Monitoring July 15, 2015: 

~1 degree Celcius Warmer than usual Sea surface temperature was observed around Maldives. Indian Ocean Dipole is active.




Predictions

Weekly Rainfall Forecast:

According to NOAA models, the total rainfall between 22nd- 27th shall be about 50 mm in northern and north central islands of Maldives.



Seasonal Rainfall and Temperature Prediction:

As per IRI Multi Model Probability Forecast for August to October, the total 3 month precipitation shall be climatological. The 3 month average temperature has a 50- 60% likelihood for northern islands and about 80% likelihood for southern-most islands to be in the above-normal tercile during this period. El Niño usually is associated with higher rainfall in the central and northern islands from October to December but lower rainfall in the southern islands until November.



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