Date of Issue: April 14, 2023
What are the usual AMJ conditions?
| April-May-June RAINFALL CLIMATOLOGICAL NORMAL (30YEARS) |
||
|---|---|---|
| Canefield Airport | Douglas-Charles Airport | |
| Normal Accumulation | 184.5 to 398.3mm | 349.9 to 636.1mm |
| Number of Wet Days | 29 to 45 days | 41 to 64 days |
| Number of 7-day Wet Spells | 1 to 4 | 1 to 5 |
| Number of 7-day Dry Spells | - | - |
| TEMPERATURE (15YRS AVERAGES) | ||
| Average Maximum | 31.5°C to 32.1°C | 29.8°C to 30.2°C |
| Average Mean | 27.5°C to 28.0°C | 26.7°C to 27.2°C |
| Average Minimum | 23.4°C to 23.9°C | 23.7°C to 24.1°C |
What is the forecast for this AMJ season?
- Rainfall:
- This period marks the transition from the dry season to the wet season;
- Forecast indicates little information on rainfall totals at this time; however, the chance of widespread, extremely high or extremely low rainfall totals is likely to be low;
- An increase in the number of wet days is likely, particularly over the western and southern parts of the island;
- No significant shift in the number of very wet spells which could result in flash floods is expected, with the usual one event likely;
- At this time, there is no concern for drought conditions;
- A high chance of bush fires is expected through April;
- Temperature:
- Temperatures are expected to be mostly comfortable and heat stress should not be a significant concern through April;
- Daytime and night-time temperatures are likely to be close to the usual, with slightly warmer nights in western regions;
- The Caribbean heat season begins in May, when temperatures generally begin to increase;
Note: The level of forecast accuracy and certainty decreases as the time increases. This is inherent to all model projections. Therefore, there is less confidence after 48 hours. Model projections may change significantly daily.
What factors are influencing this forecast?
- El Niño Southern Oscillation (ENSO)
- Recent observations: Sea Surface Temperatures (SSTs) in the eastern Pacific have risen and there was a shift from La Niña to ENSO neutral conditions by mid-March;
- Model forecast and guidance: The forecast models indicate ENSO neutral conditions are likely in AMJ (80% confidence) and either remaining so in JAS (30-40% confidence), or possibly transitioning to El Niño conditions from then onwards (55-65% confidence);
- Expected impacts on rainfall and temperatures: ENSO neutral offers little contribution to seasonal forecasting, but a transition into El Niño more often than not is marked by a delayed onset of the wet season, a drier summer season and lower Atlantic Hurricane Season activity;
- Climate conditions in the Tropical North Atlantic (TNA) and the Caribbean Sea
- Recent observations: SSTs have hovered around 0.5°C above average in much of the sub-tropical North Atlantic, but are near average in the Caribbean Sea and the Tropical North Atlantic (TNA);
- Expected conditions: Models are forecasting SSTs to remain between 0-0.5°C above average, across the Caribbean and the Tropical North Atlantic (TNA);
- Expected impacts: Warm SSTs in and around the Caribbean tend to contribute to higher air temperatures with above-average humidity and an increased frequency of heatwaves during JAS, but also higher Atlantic Hurricane Season activity, seasonal rainfall totals in an increased frequency of extreme rainfall during the summer season;