HUNTSVILLE, Ala. (AP) - Forecasters say it's going to be a cold morning across north Alabama. The National Weather Service has issued a freeze warning for the Tennessee Valley region including Huntsville, and a frost warning is out for much of north-central Alabama. Predictions say the temperature could fall into the upper 20s in places including Florence, Athens and Scottsboro early Friday. Temperatures in the low 30s could mean frost in cities including Birmingham, Gadsden and Jasper. The Alabama Farmers Federation says the cold weather could affect agriculture since more than half of Alabama's soybean and cotton crops are still in fields. High temperatures are supposed to rise into the 50s by mid-afternoon.