Warm Nose
The killer of all SE snow events as described by many. A warm nose is a layer of warm air that usually appears between 875 and 750mb that switches snow to sleet, freezing rain, or rain during winter precipitation events.
Cause
The most typical cause of a warm nose is a NW tiled low pressure complex. In this case the 700mb and 850mb low centers are well to the NW of the surface low. While the winds in lowest levels have a northerly component as you increase with height these winds veer to a more southerly/easterly direction. This veering of wind aids in advancing warm air northward into the cold dome warming the mid layers causing a ptype transition.
The thicker your warm nose and the thicker/colder the corresponding colder layer below the “nose” will determine your predominant ptype. A thin warm nose often leads to sleet being your dominant precip type, while a thick warm nose supports freezing rain or rain depending on your surface temp.
