And just like that the models have shifted south and weak with the Tuesday night system only giving RDU a slight chance of light snow and rain Tuesday night.
On the other hand the models are converging on a major ice/sleet storm starting Wednesday morning and lasting through Wednesday night. This has the potential to be a devastating ice storm for the triangle with temperatures in the upper 20's throughout the event. The good news is that the temperature will warm above freezing on Thursday for after the precip exits.
The models are having a very difficult time with this system and forecast confidence remains extremely low. It could completely change again.
Sunday, February 9, 2014
Saturday, February 8, 2014
Winter Storm ALERT! 2/8/14
Potential significant winter storm late Tuesday through Wednesday.
A rain/snow mix could begin late Tuesday before quickly changing to all snow and continuing through the night into Wednesday. The snow may mix with and potentially change to light sleet and freezing rain, ]near the end of the potential precip. The amount of precip associated with this type of classic southern winter storm could be significant. One model is weaker with the system and produces less snow than some of the other models, but it is an outlier and as of now is being disregarded by the National Weather Service Model diagnostic team. This same team is essentially going with a blend between the medium and high impacts shown by the models (But not the highest impact North American Model which gives almost all of North Carolina 13 inches of snow!). Models show anywhere from 4 to 13 inches at this time. It's still too early to officially predict potential snowfall amounts.
Potential impacts:
- Snow potentially mixing with and transitioning to sleet then freezing drizzle.
- Significant accumulations of snow possible, well above warning criteria...Ice accumulation appears minimal at this time for RDU, but could change if the surface low trends stronger and warmer. In this scenario we could get a major ice storm, but it's not predicted by the models at this time.
- High uncertainty exists on amounts and timing of start time and any potential changeover.
A rain/snow mix could begin late Tuesday before quickly changing to all snow and continuing through the night into Wednesday. The snow may mix with and potentially change to light sleet and freezing rain, ]near the end of the potential precip. The amount of precip associated with this type of classic southern winter storm could be significant. One model is weaker with the system and produces less snow than some of the other models, but it is an outlier and as of now is being disregarded by the National Weather Service Model diagnostic team. This same team is essentially going with a blend between the medium and high impacts shown by the models (But not the highest impact North American Model which gives almost all of North Carolina 13 inches of snow!). Models show anywhere from 4 to 13 inches at this time. It's still too early to officially predict potential snowfall amounts.
Potential impacts:
- Snow potentially mixing with and transitioning to sleet then freezing drizzle.
- Significant accumulations of snow possible, well above warning criteria...Ice accumulation appears minimal at this time for RDU, but could change if the surface low trends stronger and warmer. In this scenario we could get a major ice storm, but it's not predicted by the models at this time.
- High uncertainty exists on amounts and timing of start time and any potential changeover.
Tuesday, January 28, 2014
Final prediction
I think for my final call I'm going with 4-7 inches. Snow may start a bit later as RAP continues to push timing back, but it should last a bit longer as well. Thinking the heaviest snow will fall between 10 and 11 and it could be heavy.
3 PM update.
RAP has verified well with this storm, and it now shows about eight inches. 12z 4km NAM also increased totals. Storm has over performed in north Bama and Georgia. 850 low in a good spot. Now leaning toward 5-9 inches for the triangle.
10:45 AM update
Some enhanced warming aloft could lead to a bit of sleet mixing in with the snow as well as lower liquid to snow ratios a bit. Because of this I'm going to lower the minimum amount of snow to 2 inches. I'm actually going to increase the max as well though. High resolution models are showing a bit more precip then anticipated. So while we might get more precip, some of it may fall as sleet or graupel.
So now we're looking at 2-6 inches. 6 inches if it stays a nice fluffy powder and 2 inches if sleet mixes in.
Monday, January 27, 2014
1/27/2014 9:30 PM update
No change in accumulation prediction. 3-5 inches for the triangle. In fact confidence continues to increase that we will see that 3-5 inches. I now expect precip to begin between 2 PM and 3 PM and fall as snow until about 1 AM and potentially in end as freezing drizzle by 4 AM.
Weather update 1/27/2014
My first prediction in regards to the upcoming winter weather event is 3-5 inches of snow starting late Tuesday and ending Wednesday morning for the triangle. Expect less on the NW side of the triangle (Chapel Hill) and more accumulation on the SE side of the triangle (Garner). The cut off for winter warning criteria snow will be pretty sharp and looks to be near the I85 cooridor and west of 501. So that would put all of Wake County in the 3-5 inches of snow category. Another 50 mile jog to the west and we're looking at 6-9 inches. Another 50 mile jog to the east and we're looking at 1 or 2 inches.
I'll have an update later when the GFS model run becomes available.
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