· With very few exceptions, this category consists of all rain events for the entire 6 hour period.
o 95% of the total events were all rain
o 5% of the total events rain mixed with trace frozen or freezing rain
o 75 total events
Principal forecast issues
· Significant cold air advection near the beginning of the 6 hour period may TREND the precipitation types to a rain/trace frozen mix toward the end of the 6 hour period.
· Surface wet bulb temperatures should always be used in conjunction with partial thickness to ensure that there is no shallow near ground sub-freezing layer present capable of producing freezing rain.
Vertical temperature profiles associated with rain