Weather Expectations from the Present Disturbance

28 10 2014

Dale C. S. Destin |

Disturbance

Disturbance

A weather disturbance has developed around 250 miles east of Antigua. It has a 20% chance of becoming a tropical cyclone (the generic term for depressions, storms and hurricanes) while it is in our area and a 30% chance of become a tropical cyclone after it moves away for the northeast Caribbean. However, this system is not expected to become a tropical cyclone as the winds aloft are not favourable for much further development. Notwithstanding, based on data available up to this morning, there are three weather scenarios looked at below with respect to the impact of the disturbance on Antigua and the northeast Leeward Islands.

Expected

The weather expected from this disturbance is: Cloudy to overcast skies with precipitation (rain and showers); thunderstorms are likely Tuesday night and Wednesday. Further rainfall accumulation of 10 to 25 mm is possible. The winds are going to swing to the southeast at 5 to 12 knots by tonight. The seas will get up to near two (2) metres or 6 feet tonight and will fall back to near 1.5 metres or 5 feet tomorrow Wednesday.

Best Case

For a best case scenario, the disturbance will get decimated by the unfavourable winds aloft. Thus, although cloudy skies will continue, not much more rainfall will take place.

Isaias_Intensity

Worst Case

For the worst case scenario, the disturbance could develop further and impact Antigua and Barbuda as a tropical depression and the rest of the northeast Caribbean as a minimal tropical storm (Isaias). This scenario is very unlikely; however, if this pans out, quick action would be required to protect life and property.

Isaias_Invest

Conclusion

Changes will definitely take place with this disturbance over the next 24 hours; however, something close to the best case scenario is anticipated. Notwithstanding, this system will be monitored and if the chance of development into a tropical cyclone rises to above 50%, a tropical cyclone alert will be issued by the Antigua and Barbuda Met Service. Residents in the Leeward Islands should continue to monitor this system until it has dissipated or out of our area.





Antiguan Storms During July

15 07 2013

Dale C. S. Destin |

What is Antigua’s record with respect to tropical cyclones in July? While tropical cyclones are unlikely to affected Antigua during the month of July, it is not unheard of. For the period 1851 to 2012, Antigua has been affected by six tropical storms, including one hurricane (AntiguanStorms). The last tropical cyclone to have affected Antigua in July was Hurricane Bertha in 1996. The system produced 39 mph sustained winds with gusts near 60 mph.  Total rainfall from it, measured at the airport was 49.1 mm. Based on the active multi-decadal period that we are in, which started around 1995, the probability of a storm or hurricane affecting Antigua is 5% (one every 20 years) as compared to the (1981 – 2010) normal of 3% (one every 33.3 years). Broadly speaking, we a not due another storm in July until sometime in the period 2016 – 2029. Meanwhile, a major hurricane has never affected the country during July.

Two tropical storms formed during the month of June in the North Atlantic Basin. Based on a 30-year (1981 – 2010) average, a tropical storm forms in June in the basin about once every other year.








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