For the Triangle today’s event unfolded about exactly as I forecasted it. We saw generally an inch or less of snow change to sleet and freezing rain with a glaze of ice, but most areas have been seeing light rain the last hour or two with temperatures right around 32 but just off the ground and up several thousand feet is above freezing. This is allowing the rain to freeze on some exposed surfaces like tree limbs but for the most part the ice accrual is letting up across the Triangle. Areas north and northwest of the Triangle could see freezing rain persist into the afternoon but most areas should warm above freezing this evening.
My attention now turns to Saturday afternoon and night. The models have really been waffling on this event the last several days and the latest trend is back towards a winter storm for some parts of the state Saturday evening and night. A storm system current moving into California will take a southerly route the next couple of days and spark the development of low pressure in the Gulf of Mexico. Some energy from the northern branch of the jet may drop in and cause this storm system to develop far enough to the north and west to cause precipitation to re-develop across southeast Saturday and Saturday afternoon. Enough cold air is going to be around for the northwest section of the precipitation to fall in the form of snow. The 12z GFS has trended wetter and would produce a significant snow event for areas of the central and eastern piedmont, northern coastal plain and southeast Virginia. The 00z and 12z ECMWF have also trended wetter and would be a moderate to significant snow event as well. The NAM has been somewhat aggressive as well and trended west with the 12z run versus the 6z run. It certainly looks like the model trend is towards an event today, but we still have 48 hours before the event gets here so it is time to watch.
Beyond this, the models have also been showing a possible light snow threat from a clipper on Tuesday and then looking down the road they also showed another strong clipper with possible coastal redevelopment around Christmas Eve and Christmas Day. However, there is plenty of time for these model simulations to change, but as long as a strong 500mb low remains over the northeast we will see frequent northwest flow systems (clippers) with similar results to the last two systems.
The westward based –NAO block still shows in the models through at least New Years Eve and thus it looks like a colder than normal pattern in the southeast will continue into early January at least.