Trinidad and Tobago Dryness Monitor and Outlook By End of December 2021



ISSUED AT: 02:57 PM

Date: Monday 25th of October 2021

Key Message

No concern for short-term impactful dry conditions over the next three months, as the predicted rainfall amounts are expected to be sufficient to overcome any short duration drying impacts.

Dryness Indicator for July to September 2021

Observed rainfall totals over the period July to September exceeded the aver...


Trinidad and Tobago Dry/Wet Spell Monitor and Outlook by End of December 2021



ISSUED AT: 02:57 PM

Date: Monday 25th of October 2021

Key Message

No concern for short-term impactful dry conditions over the next three months, as the predicted rainfall amounts are expected to be sufficient to overcome any short duration drying impacts.

Dryness Indicator for July to September 2021

Observed rainfall totals over the period July to September exceeded the average totals at all selected sites except  at sites in northeast Tobago, where there was a dryness indicator of negative 0.5 (-0.5). This represents borderline dryness on the dryness indicator scale for areas close to Hillsborough in northeast Tobago and overall wetness elsewhere across the country. There were no concerns for dryness impacts.

The colour-coded dryness indicator map showing observed level of dryness for the three months July to September 2021 is based solely on rainfall and can be used for decision making or for heightening awareness on dryness.

Figure 1. The colours on this map show observed dryness levels based on the rainfall differences from average, which have been standardized and expressed as the number of standard deviations less than average. The period used to compute the dryness is  the  3-month period July  to  September  2021 compared to the historical average for the same 3-month period. The yellow to red colours on the map are used to indicate areas with borderline-dry to extremely-dry levels of dryness. The grey colour indicates areas where there is no significant dryness concerns.

Dryness Outlook for October  to December 2021:

The Dryness Outlook for the 3-month period, October to December 2021 indicates favourable rainfall most likely with the only area with rainfall deficits likely to be in northeast Tobago. However, there is no concern for impactful dry conditions over the next three months, as there is likely to be sufficient rainfall to buffer pockets of deficits expected in November.

Dryness indicator values for the period are between 0.2 and 1.1 on the Standardized Precipitation Index (SPI) scale for Trinidad, which are on the wet-side and outside of the levels for dryness concerns. In southwest Tobago, the indicator is 0.3 while it is -0.35 in the northeast. The outlook is based solely on rainfall and should be used only as a guidance tool.

 

Figure 2. The colours on this map show the predicted levels of dryness for the period October to December 2021.  It is based on the standardized accumulated rainfall (observed and predicted) difference between July to December 2021 and the historical average rainfall for the same period. The yellow to red colours indicate borderline dry to extremely dry levels of dryness. The grey colour indicates areas where there is no significant dryness concerns.