SAN JOSÉ, Costa Rica — The National Meteorological Institute (IMN) has issued a weather advisory as Tropical Wave #45 passes over Costa Rica on Saturday, September 19. The system is expected to cross the territory during the afternoon and early evening, significantly increasing atmospheric instability across the nation.
Authorities advise residents and travelers to remain cautious, particularly in areas prone to flash flooding, landslides, and lightning activity.
What to Expect Region by Region
🌅 Morning: Warm and Humid Conditions
The day will begin with warm, humid conditions across most of the country. Early coastal showers are anticipated along the South Pacific coast, while other regions can expect partial cloudiness and rising temperatures through midday.
⛈️ Afternoon: Mountain and Valley Thunderstorms
As Tropical Wave #45 interacts with local daytime heating, atmospheric instability will peak. Scattered heavy showers and thunderstorms are expected across:
- Mountainous Ranges: Central, Tilarán, and Guanacaste ranges.
- Central Valley: Low-lying urban areas including San José, Alajuela, and Heredia.
- Northern Zone (Zona Norte): San Carlos and surrounding lowland sectors.
- Nicoya Peninsula: Inland and elevated sections.
💡 Traveler Advisory: Drivers in the Central Valley and mountainous passes (such as Route 32 and Cambronero) should prepare for reduced visibility and heavy downpours during peak afternoon travel hours.
🌙 Night: Rainfall Shifts to the Pacific Coast
Into the evening hours, precipitation is projected to transition toward the broader Pacific coastline, maintaining wet conditions into the night from the North Pacific down through the Osa Peninsula.
⚡ Safety Tips for Heavy Weather in Costa Rica
- Watch for Rising Rivers: Stay clear of stream beds and riverbanks in high-risk zones.
- Lightning Precaution: Seek shelter immediately when thunder is heard, especially in open fields or exposed areas.
- Road Safety: Drive with headlights on, maintain low speeds, and watch out for fallen tree branches or mudslides on rural routes.
- Stay Updated: Monitor official updates directly from the National Meteorological Institute (IMN) and emergency response channels.
