Weather Underground Forecast for Friday, November 20, 2009.

The Tropical Atlantic and Caribbean Sea are not expected to see tropical storm development on Friday. However, a few interesting weather features will bring areas of unsettled weather over the region. A strong low pressure system will spin over the Northwestern quadrant of the Gulf of Mexico. This will bring moderate to heavy showers and thunderstorms to the surrounding coastal regions as ample moisture feeds energy into this system. Only a few of these showers will reach into northeastern Mexico on Friday. Meanwhile, to the southeast, a linger frontal boundary will slowly continue to track eastward and out of the region. On Friday, this front will extend from the Bahamas, over Cuba, and into the Yucatan Peninsula. Light scattered showers are expected to pop up along this front.

To the south, a trough of low pressure will hover over Panama and create another day with strong onshore flow from the Caribbean. This moist flow will bring lighter showers to eastern Costa Rica as well as northern Panama. Strong storms are not expected to develop over these countries on Friday.

In South America, wet weather will diminish over the northern countries. However, onshore flow from the Pacific will continue triggering scattered showers with isolated storm development over Colombia, Ecuador, and Peru. To the south, a low pressure system will push offshore from southern Brazil and create a strong front that will move northward through northern Argentina, Paraguay and into southern Brazil. At the same time, high pressure will build over Chile and dry out the region from the south. Expect scattered thunderstorm development in Sao Paulo with highs in the lower 80s(F)/ mid- 20s(C), while Santiago will see a few clouds with highs in the upper 70s(F)/ mid-20s(C).