Holiday weekend forecast; high-pollution advisory

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PHOENIX -- Warmer afternoons are in store for the Valley as we head into the last weekend of 2011. 

A ridge of high pressure is keeping skies mostly clear, with plenty of sunshine and above average temperatures across the state. 

Friday, the Valley is expected to top out near 73 degrees, with a high of 76 forecast for Sunday, New Year's Day. 

These highs in the mid-70s are about 10 degrees above average for this time of year.

A health watch for pollution is in effect for the Valley Friday. Shortly before 12:30 p.m., the Arizona Department of Environmental Quality issued a high-pollution advisory for Saturday and Sunday, the last day of 2011 and first of 2012.

"History has shown that the smoke from wood-burning and firework activities typically send pollution levels well above the health standard on New Year's Eve and New Year's Day," said ADEQ in an email alert. "This year will be no different as the weather pattern is very favorable for unhealthy PM2.5 [fine particulate matter] levels."

Light winds and an overnight inversion are trapping smoke particles and other pollutants near the surface, making for unhealthy breathing conditions.  It's also a "no burn day" in Maricopa County, which would also be extended through the weekend if the air quality readings do not improve. 

For New Year's Eve, look for temperatures in the low 50s around midnight under clear skies.