Warm Mediterranean raises risk of intense autumn rain in Murcia

AEMET warns that the Region of Murcia has several of the ingredients needed for intense rainfall, with sea temperatures close to 30°C adding extra moisture to the atmosphere

The Mediterranean is heading into autumn with sea temperatures well above normal, which could have an important bearing on the weather in the Region of Murcia over the coming months.

AEMET has stated that the Region already has several of the ingredients needed for a potentially very wet and intense episode like a DANA. What remains unknown is whether the atmospheric conditions needed to bring those ingredients together will develop.

Sea temperatures approaching 30°C were recorded at the surface in parts of the Mediterranean this summer. Warmer water means more moisture and energy are available to the atmosphere, which can help fuel heavy rainfall when there is sufficient atmospheric instability.

The important point, however, is that warm seas don't mean a DANA is definitely on the way. AEMET cannot predict several months in advance whether one will form, where it would move or exactly where the heaviest rain would fall. Small changes in the position of a DANA can make a huge difference, potentially shifting the areas receiving the heaviest rainfall by hundreds of kilometres.

There is some indication that Murcia could be wetter than usual during the September to November period. AEMET's seasonal forecast puts the chance of above-average rainfall at 40%, compared with 25% for a drier-than-normal autumn.

That doesn't mean the rain will be spread evenly across the season, either. A wetter autumn could involve ordinary spells of rain, one or more intense episodes, or a mixture of both.

Recent events in Cartagena have also shown why keeping an eye on the details in AEMET's warnings is so important. On September 17, a red warning was issued for heavy rain in the Campo de Cartagena and Mazarrón after some areas recorded more than 60 litres per square metre in an hour.

AEMET stressed that people should always read the comments accompanying weather warnings, as these can provide important information about where conditions are expected to become most difficult.

The Cartagena episode also showed how quickly things can change. The red warning was introduced as rainfall intensified and was later downgraded as the worst of the weather moved away.

For Murcia, the message going into autumn is not that a DANA is on the way, but that the conditions could be there for very heavy rain if one develops.

Images: Cartagena town hall