Compared to average dry-seasons and last year’s record-breaking dry-season, the 2021 Dry Season is likely to produce more rainfall than usual overall, over most areas, but a lot of dryness is still likely.
Localized rainfall events are likely to push the monthly rainfall totals to above-average from just a few rainy days during the month.
After considering waning rainfall rates, the absence of typical wet-season weather systems and the increasing presence of dry-season weather and climatic features, the Trinidad and Tobago Meteorological Service declares that the 2021 dry season has started. The season is being ushered in by slightly cooler temperatures, relative lower humidity levels, and much stronger lower-level wind speeds. This is due in part, to an enhanced North Atlantic Sub-Tropical High (NASH) pressure system that has shifted its center further eastward, extended its reaches southward and to greater vertical depth, compared to 2 to 3 weeks ago. The shifting and strengthening of the NASH in recent weeks have also led at times, to an enhanced trade wind inversion and at other times to the presence of subsidence inversions. Together, these features have acted as suppressors of significant rain-bearing cloud development and are typical indicators of the region having transitioned to its drier state.
What to Expect
A less drier than average dry season is favoured across Trinidad and Tobago. The country can expect rainfall to generally be more localized, but some moderate to heavy rainfall events after several days of dryness can push the monthly rainfall totals to above average totals in just a few rain days. Above-average rainfall conditions in the dry season, often does not mean plenty rainfall.
Meanwhile, the odds are tilted towards the country experiencing a warmer than-average dry season, but some nights will be chilly in the first two months of the season, as relatively colder air is likely to funnel and encroach into the region due to the location of the sub-tropical high pressure system and migrating weather systems from colder latitudes. At the same time, the months of April and May are likely to produce one or two short duration hot spells.
Kenneth Kerr
Chief Climatologist, Trinidad and Tobago Meteorological Service
