Heavier than expected rainfall was observed over the Northern and Central
in the second half of August and the rainfall was diminished in the first two
weeks of September. However, these rainfall has not compensated for the sustained
drought persisting over the Northern and Maldives . Warming sea surfaces around Central Islands Maldives and the tropical have contributed
towards these conditions. But in Eastern Pacific
Oceans South Maldives, where the rainfall deficit over the last
year was smaller, the heavier than expected rainfall compensated for the
drought conditions to some extent.
Image: Rainfall in 2012 (black) compared to rainfall in previous 5 years in Northern Maldives
Image: Rainfall of past 365 days (black) compared to average rainfall in previous 8 years. Note the continuous increase in rainfall deficit.
The climatology refers to the average conditions experienced historically for a given month. Usually the climatology is a good guide to what one may expect in a given month absent other information. The historical average rainfall for the Northern islands is high in July (200-
250 mm), higher in August (250- 300 mm) and drops in September
& October (100- 200 mm).
In the Central islands rainfall is
usually moderate (150- 200 mm)
during the August – October period. Heavy rainfall is typical for the Southern
islands during these four months. The winds over the Northern & Central islands
are usually westerly (from West to East) and wind speeds are expected to be
high. For Southern islands, low wind speeds are expected for July and August but
stronger westerly winds in September and October.
mm rainfall was estimated to have fallen over Northern
and Central islands of
on the 10th of September. For the 11-15th of September,
very little rainfall was observed over all of Maldives . Maldives
Monthly and Seasonal Monitoring:
The rainfall this August has been higher than that during the previous 5 Augusts. But by September, the rainfall gradually decreased this year. In Central islands, high rainfall was observed in mid August which is also the highest amount of rainfall observed in this region for this year. High rainfall was observed in South islands in August as well, which diminished by the start of September. Afterwards a gradual increase in rainfall is observed for the first two weeks of September. Despite high rainfall in
in the past month the
deficit of cumulative precipitation compared to past 8 years continues to
increase. Even in islands in the South of Maldives where cumulative
precipitation has been almost equal to the average, this deficit has become
Sea Surface Temperatures and ENSO state:
Ocean, the ENSO state is moving towards an El Nino state. Most
models predict a transition in the coming months. The unusually warmer sea surfaces
of the Central Western Indian Ocean are stronger than normal during El Nino
periods. Past work has shown that these conditions lead to lower than average rainfall
in Sri Lanka and Northern Maldives upto September. Thereafter the rainfall is likely to be
higher than average for October to December.
Weekly Rainfall Forecast:Dry conditions are expected for Maldives for the period of 19th -24th of September 2012.
Seasonal Rainfall and Temperature Prediction:As per IRI Multi Model Probability Forecast for September 2012 to January 2013, there is a 40- 50% probability for precipitation to be above normal. Furthermore, there is 50% probability for Temperature to be above-normal.
ENSO UPDATE 20th September, 2012
More than 80% of the ENSO prediction models predict El Nino SST conditions during the September- November season, continuing into Northern winter 2012-13. Among those predicting El Nino, very few predict more than a weak event.
(Text Courtesy IRI)
Inside this Issue
1. Monthly Climatology
2. Rainfall Monitoring
a. Daily Satellite derived Rainfall Estimates
b. Monthly Rainfall derived from Satellite Rainfall Estimate
c. Monthly and Seasonal Monitoring
d. Weekly Average SST Anomalies
3. Rainfall Predictions
a. Weekly Predictions from NOAA/NCEP
b. Seasonal Predictions from IRI