Subseasonal forecast

Valid from    octuber 28 to november 24 , 2024

(4 weeks)

General comment:

The last week of October and the first week of November will see very rainy conditions on the Pacific side, but this rainfall will gradually decrease in the second and third week of November. The Caribbean will continue with little rainfall in the coastal areas and rain in the mountains.

Fig. 1. Weekly precipitation forecast by region for the next 4 weeks.

 

1.Forecast from  octuber 28 to november 3, 2024

This week, rainfall will tend to decrease compared to previous weeks in the Pacific, with 15 to 20% less rainfall (in the week) in the Pacific and throughout the Caribbean; Central Valley and Northern Zone with normal accumulations (weekly rainfall between 20-40 mm in the Caribbean and less than 100 mm in the Pacific).

Probability of extreme: low (around 20%)
Forecast uncertainty: low

2.Forecast from  november 4-10, 2024

This week there will be normal rainfall in the Pacific compared to previous weeks, returning to a normal-dry rainfall scenario in the Pacific, Central Valley and Northern Zone. The Caribbean will also have normal conditions (accumulations between 20-40 mm per week in the Caribbean and less than 80 mm in the Pacific).

Probability of extreme event:  low (around 20%)
Prognosis uncertainty: medium

3. Forecast from  november 11- 17, 2024

This week, normal rainfall will continue throughout the Caribbean and the Northern Zone (accumulated between 20-60 mm per week in the Caribbean and more than 120 mm in the Pacific). In the Pacific, the last days of October and the beginning of November will see slightly above-normal rainfall (over 150 mm per week).

 

Probability of extreme event: low (around 30%)
Prognosis uncertainty: medium

4. Forecast from  november 18-24, 2024

Very weak trade winds and the presence of the Intertropical Convergence Zone over the country. The Intertropical Convergence Zone is expected to favor rainy conditions throughout the Pacific and Central Valley.

Probability of extreme event: low (around 20%)
Prognosis uncertainty: high

 

Forecast of extreme events from  octuber 28 to november 3, 2024

During this period there is a high probability of tropical cyclones developing in the Caribbean Sea, north of Colombia, there is a probability that the Intertropical Convergence Zone will be activated near the Pacific in Costa Rica, generating very rainy conditions throughout the Pacific and Central Valley the week of October 28 to November 4.

Fig. 2. Forecast of extreme events for the next 2 weeks (training areas).

 

 

Forecaster: Daniel Poleo
Maps: Nury Sanabria Valverde
Unidad de aplicaciones climáticas
Departamento de Desarrollo/IMN