A mass of polar air linked to a cold front will generate risk of weak and scattered outbreaks of frost, notably in the relatively small producing area of north Parana, early on Friday, private meteorologists Somar said on Monday.
"The risk is highest in northern Parana where temperatures could fall below 2 Celsius (35.6 Fahrenheit) at dawn on Friday," Somar said in a daily report.
Somar added that a high-altitude jet stream would weaken the mass of polar air and push it toward the Atlantic ocean. It noted disagreement between regional, national and North American forecasting models about the intensity of the mass of polar air. Only the North American model, which Somar uses, forecast temperatures below 3 Celsius. However, all models identified a jet stream above Parana that would weaken the polar air mass moving northward from Argentina.
The cold front will trigger rain between Monday and Wednesday in coffee areas between Parana and forested areas in Minas Gerais and Espirito Santo state.