Government of the Commonwealth of Dominica Website
Tuesday, 22 January 2019

Dominica’s 2017 Wet-Season Outlook.

Dominica’s wet season runs from June to November each year. Above to normal rainfall totals are forecast for the first half of the 2017 Wet Season with a shift to below to normal rainfall totals in the second half of the season. As Dominica transition from the dry to the wet season an increase in the frequency of wet days (≥1.0mm) and wet spells are anticipated. There are no drought concerns for the island at this time. However, please keep updated in the coming months. Both day and night-time temperatures are forecast to rise and become warmer than normal. There is a high probability for the occurrence of heat waves in the coming months.

Flash flooding is a major concern with the possibility of extreme wet spells. Outdoor activities are expected to be disrupted on many occasions due to increase rainfall days. Wet environmental conditions tends to result in an increase in pests and diseases like mosquitoes. Water availability is not expected to be a concern.

Normally, rainfall accumulated for the wet season falls between 1000 to 2000mm on the coastal regions with higher amounts in elevated region. Average temperature ranges from 26 to 28°C on the east coast to approximately 27 to 29°C on the west coast with cooler temperatures in the interior. On average maximum (day-time) temperatures range from 31 to 33°C on the west coast to 30 to 31°C on the east coast.  Average minimum (night-time) temperatures ranges from 23 to 25°C.

The 2016/2017 Dry Season which ran from December 2016 to May 2017 recorded a wetter than normal dry season with above to normal seasonal temperatures. A transition from La Niña (cooling of the Eastern Equatorial Pacific Ocean) to El Niño Southern Oscillation(ENSO) neutral phase occurred during the start of 2017. Normally, La Niña tends to result in an increase in rainfall activity in the Eastern Caribbean while ENSO neutral conditions have little effect on rainfall or temperatures. Slightly-above to normal Caribbean Sea and Tropical North Atlantic Sea Surface Temperatures (SSTs) contributed to increase humidity over the region which in turn lead to increased rainfall. A transition to El Niño (warming of the Eastern Equatorial Pacific Ocean) phase is anticipated during the 2017 Wet Season. El Niño conditions normally results in a decrease in rainfall activity in the Eastern Caribbean. However, El Niño tends to result in high intensity rainfall events and an increase in temperatures 2 to 3 months after its onset, boosting chances of a hot August to October period. A weak El Niño during the first half of the wet season may not have any significant effect on rainfall. However, it may lead to a decrease in rainfall activity towards the end of the season.

This forecast was prepared during the Caribbean Climate Outlook Forum (CariCOF) held in St. Vincent and the Grenadines from May 29th to June 2nd 2017.

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