After a much wetter May than average, rainfall across Maldives has been drier than average for July and August. There still is a cumulative rainfall anomaly compared to the past 8 years’ average in Northern and Central islands in Maldives while in Southern islands it is close to average cumulative rainfall. Sea Surface Temperature around Maldives has remained in a climatological state during the past two weeks but In the larger Indian Ocean there is a negative dipole.
Image: Observed rainfall (Top) and Rainfall Deficit in North Maldives (Bottom)
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.
Weekly Monitoring:During 23rd -28th July Northern islands received rainfall except on the 26th where rainfall was on southern islands.
Monthly and Seasonal Monitoring:
Rainfall continues to follow a diminishing trend after having a wet April/ May. Rainfall deficit in Southern and Northern islands is negligible while in Central islands rainfall deficit compared to the average rainfall in the past 8 years is still evident.
Sea Surface Temperatures and ENSO state:
There is negstive Indian Ocean Dipole while the sea surfaces around Maldives are near-neutral. The ENSO state continues to be neutral with a few models predicting a La Nina tendency. The sea surfaces around Maldives have cooled significantly – the rest of the Indian Ocean shows neutral conditions except that there is a strong warm anomaly in the western Indian Ocean near Sumatra – thus there is an emerging Negative Indian Ocean Dipole. The Pacific Ocean surfaces show a tendency to La Nina but it was not emerged fully as yet. A negative IOD and La Nina usually leads to slightly increases in rainfall over the next 3 months followed by stronger declines from September to Dececember.
Weekly Rainfall Forecast:Extreme rainfall events are not expected during 29th Jul -3rd of August.
Seasonal Rainfall and Temperature Prediction:As per IRI Multi Model Probability Forecast for August to October 2013 rainfall shall remain climatological while temperature this season shall be 40- 50% above normal.
Pacific Seas State July 18, 2013
During June through early-July the observed ENSO conditions remained neutral. Most of the ENSO prediction models indicate a continuation of neutral ENSO through the remainder of autumn. However, a few models, mainly statistical models, call for cooling towards borderline or weak La Niña conditions for Northern autumn into winter while a few others, mainly dynamical, forecast developing El Nino conditions during this same time frame.
(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