FPUS42 KMLB 251013 City Forecast for Fort Pierce, FL Issued Wednesday morning - Nov 25, 2009 .Wednesday... Thunderstorm, high 79, 90% chance of precipitation. .Wednesday night... Low 63, 70% chance of precipitation. .Thursday... Partly cloudy, high 76, 30% chance of precipitation. .Thursday night... Low 52. .Friday... High 66.