IRI Climate Information Digest - September 1998
Issued 14 October 1998, Next
Issue 13 November
percentile NOAA NCEP CAMS_OPI mean precipitation
Highlights Monsoon Rainfall Season
The 1998 summer monsoon was characterized by abundant rainfall in most
areas over India. In Bangladesh, tropical storm activity in combination
with higher than normal sea levels produced severe flooding. Abundant
rainfall characterized the western African monsoon with drier than average
conditions along the Gulf of Guinea. The remnants of the 1997 - 1998
ENSO warm episode influenced the evolution of the North American Monsoon
System but the season ended with near average with rains from the remains
of tropical storm ISIS.
The ENSO cold episode – La Niña
The La Niña episode continues to develop
at about the predicted pace with most models calling for a peak early in
1999. Relatively cold water is now in place from the East Pacific
extending to the dateline. However, relatively warm water, remnants
of the El Niño warm episode, remain south
of the equator in the east Pacific.
Southeastern Asia and eastern China
Myanmar through Vietnam and into eastern China experienced large rainfall
deficits in July to September. Dry condition extended eastward through
the northern Philippines. Dry conditions over Southeast Asia and
the Philippines were somewhat alleviated by late season showers.
Heavy rains returned to Indonesia consistent with developing La
September Atlantic TROPICAL STORM Activity
September saw eight named storms (Danielle, Earl, Frances, Georges,
Hermine, Ivan, Jeanne and Karl) and for the first time this century, on
September 24, four Atlantic hurricanes were active at the same time. Enhanced
hurricane activity is consistent with developing La
Niña conditions. Tropical Storm Frances brought flooding rains
to drought affected areas of Texas northward through Missouri. Hurricane
Earl brought heavy rains to the dry southeastern United States. Hurricane
George was a destructive influence from the Caribbean through the southeastern
Averaged global temperatures remain at record high levels through September.
Temperatures were notably above average levels over much of North America
and Eurasia for the July through September period.
The evolving La Niña is not expected to have a substantial effect on global temperatures
until the end of the year.
Forecasts - for temperature and precipitation
Impacts - on fisheries, agriculture, and hazards.