Heavy rain and thunderstorms are forecast for parts of the Balearic Islands, southern, south-central and eastern Spain until at least September 22. The heaviest rainfall is expected in Ibiza and Formentera in the Balearic Islands, where hourly rainfall totaling 5 cm (2 inches) is possible at the end of September 21-22. Showers and thunderstorms could break out across much of the affected area on September 21 before adverse weather conditions are largely concentrated in the east and the Balearic Islands on September 22. Thunderstorms can be accompanied by strong gusts of wind, lightning and possible hailstorms.
As of September 21, the Spanish National Meteorological Agency (AEMET) has issued the following weather warnings in the affected area:
Orange heavy rain warning (mid level on a three level scale): Ibiza and Formentera in the Balearic Islands.
Yellow Heavy Rain Warnings: Parts of southern Aragon, central and southern Castile-La Mancha, southwestern Catalonia, southern Extremadura and the western, central and northwestern autonomous communities from Valencia, as well as from the south and interior of Majorca in the Balearic Islands.
Yellow storm warnings: Throughout the affected area.
Authorities could update and possibly expand coverage of weather warnings over the next few days.
Sustained heavy rains could trigger flooding in low-lying communities near rivers, streams and creeks. Urban flooding is also possible in developed areas where stormwater drainage systems are easily overwhelmed or lacking. Sites located downstream of large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rains have saturated the ground. Disruptions to electrical and telecommunications services are possible when major floods or landslides affect utility networks.
Floodwaters and debris flows can render some bridges, rail networks or roads impassable, impacting overland travel in and around affected areas. Puddling of road surfaces could lead to hazardous driving conditions on regional highways. Authorities may temporarily close some low roads that are inundated by floodwaters. Extreme weather conditions could also lead to flight delays and cancellations at regional airports. Floods could block regional rail lines; freight and passenger train delays and cancellations are likely in areas that experience heavy rain and possible track flooding.
Localized business interruptions may occur in low areas; some businesses may not be operating at full capacity due to facility damage from flooding and the inability of some employees to get to job sites.
Monitor local media for weather updates and advisories. Confirm all transportation reservations and business arrangements before traveling to affected areas. Obtain up-to-date information on road conditions before driving or routing expeditions in areas where extreme weather conditions are expected; plan for possible supply chain disruptions in affected areas. Stay away from high streams, creeks and other waterways prone to flash flooding. Do not attempt to navigate flooded roads. Use caution in high terrain due to the threat of landslides, as well as in mountainous areas where avalanches pose a threat. Charge battery-powered devices during extended power outages.
Agencia Estatal de Meteorologia (AEMET) (Spanish)