Early Warning Status: September 2020

Submitted by admin on Wed, 09/30/2020 - 08:45

Disclaimer: The weather forecast outlook is based on models which consider the various climate influences. These have a degree of probability and therefore some risk in the accuracy of the forecast. The development and improvement of these models is ongoing among our regional partners with the PNG National Weather Service.

At this time we can expect higher than normal rainfall over the coming months. All key indicators of the El Niño–Southern Oscillation (ENSO) have now reached or exceed La Niña thresholds. The ENSO Outlook has been moved to La Niña (http://www.bom.gov.au/climate/enso/outlook/). The Australian Bureau of Meteorology advises that all the climate models surveyed indicate further cooling is likely, and that La Niña thresholds will likely be sustained at least into January 2021. A La Niña brings the need to plan for higher and more intense rainfall than normal, and associated risk of erosion, landslides, flooding and excess soil moisture which could harm susceptible crops. It is recommended that farmers prepare by choosing suitable crops, avoid or take precautions with flood and land-slip prone areas, and adopt soil conservation and drainage practices for the coming wet season.

lanina watch September 2020 OND

The following is extracted from the PNG National Weather Service:

“It is becoming more and more likely that we may be seeing a La Niña event developing any time soon judging from the way the atmosphere is beginning to respond favourably to the changes that is happening in the oceans. It is anticipated that if the current atmospheric patterns and oceanic cooling continues until the end of September, it is highly likely that the La Niña conditions will be sustained until at least the end of the year or early 2021. In other words, this La Niña event will be weak and short-lived. The main factor that gives rise to the strength and therefore the longevity of the La Niña event is the heat content in the ocean, especially the top 100m depth of the ocean. This latent heat stored in the oceans are responsible for convection (rainfall) through condensation and so the greater this energy, the longer it will sustain itself. The current observations and assessment of the sea surface temperatures thus far, in the top 100m depth has been slightly warmer than average. During La Niña episodes, the country, on average receives much more rainfall than it normally does. Because this La Niña event is forecasted to be coinciding with the onset of our normal wet season, the possibility of a compounding effect from this climate variability is highly likely. This amplification effect has the potential to cause heavy rainfall events and may lead to floods in low lying areas and landslides especially in the highlands therefore, evaluating possible potential impact pathways for La Niña conditions and having contingency plans in place, would be a helpful preparedness measure to reduce risks and harness favourable weather conditions.

For now, the country is feeling the impact of the dry season; however this is soon going to change as we transition into our wet season come October. With the promise of La Niña happening around this country, the country is in for more rain days.”

Please see the attached “Seasonal Climate Outlook (Oct-Dec 2020) ” from the PNG National Weather Service ( http://www.pngmet.gov.pg) for more information. Attached document: NWS_OND2020.pdf.

For more general information about climate in our region, see: