Weekend Weather Update
Rain continues to fall for the southern half of the area and this rain will slowly move out of the area from west to east over the next couple of hours. The event has been confined primarily to this southern half where rainfall totals for today are running between 0.05″ in Greenville and 0.60″+ near Wilmington.
There will be a lull in the rain overnight before the next disturbance reaches ENC. Temperatures overnight are expected to drop into the mid 40s under mostly cloudy skies.
The next disturbance to cross the region will be on Wednesday where our most southern sections could see a couple of tenths of rain before ending Wednesday afternoon. Areas to the north will experience mostly cloudy skies with high temperatures reaching the mid to upper 50s.
For the remainder of the week, a series of cold fronts will work through the area bringing temperatures down dramatically. On Friday, we are looking at morning temperatures starting in the lower 20s and highs only reaching the mid 30s. High pressure to the north will also contribute to a cold air damming situation.
It is at this point that the weekend forecast becomes a little more interesting (gives me something to write about). Cold air will be in place thanks to the high to the north. A coastal trough will develop Friday then shift northward over the area as a warm front. This has the chance to produce some precipitation over the area. With the existing cold layer at the surface, could this produce frozen precipitation? Below are a few GFS forecast soundings that I will be referencing in this post:
As we can see from these three forecast sounding profiles there is a very shallow layer below freezing near the surface under a much thicker layer above freezing. The 850mb GFS forecast map (as well as the forecast profiles above) show a persistent southwesterly flow, as a result of the progressing warm front, transporting even warmer temperatures aloft.
What this data tells us there is a chance that the precipitation could start as some freezing rain but transition to all rain quickly as the lower levels warm up. However, I am not convinced that there will be freezing rain in ENC at this time. Based on past experience applied to this forecast setup, I believe the onset of precipitation will be delayed due to the presence of dry air at the surface. With this delay, the temperature at the surface will increase enough to maintain an all liquid event. If future runs show more moisture available under similar situations, that may make me lean towards the freezing rain at onset before rain transition.
The other models are mixed in this situation. The 12Z Canadian model shows frozen precipitation over a larger area to the west than the GFS. The Euro is more inline with the GFS that shows less frozen precipitation coverage over North Carolina. None of these models today shows ENC receiving frozen precipitation which seems accurate from the data I have been seeing thus far. Update: 00Z NAM is similar to the 12Z Canadian model and my forecast for ENC remains unchanged. The 12km NAM model has a tendency of overdoing precipitation at the end of the forecast period so I caution users not to read too much into its solution. I will continue to monitor potential impact to central North Carolina in future model runs.
Could the forecast change over the next couple of days? Yes, but I wouldn’t expect a large shift in the forecast.
So, bottom line: Rain chances begin on Saturday with temperatures rising throughout the weekend.
Have a great evening and I’ll be back in the morning.