• Hello, please take a minute to check out our awesome content, contributed by the wonderful members of our community. We hope you'll add your own thoughts and opinions by making a free account!

Wintry 2/3-2/4 Mixed Bag NC, SC, NE GA

I'm already 37 (forecast low of 36) clear skies and dp of 16. hmmmm
 
Webberweather53 said:
HRRR has busted horribly on overnight lows here lately in NC, it was off by several degrees just last night and only pushed RDU into the mid 20s, we reached 17...
Click to expand...

You think it could be further east with the ice?
 
Spurs up said:
I'm already 37 (forecast low of 36) clear skies and dp of 16. hmmmm
Click to expand...

There are pockets of 34 as of an hour ago here in Lexington's area. The southwesterly flow should start to bring these up quickly before precipitation gets going, but who knows.
 
Shawn said:
There are pockets of 34 as of an hour ago here in Lexington's area. The southwesterly flow should start to bring these up quickly before precipitation gets going, but who knows.
Click to expand...
I'm down to 35 now dropped 2 degrees last hour. I don't want zr anyway so I'm good with staying above freezing!!
 
I'm down to 33 dp 17 I'd be in trouble if moisture was on my doorstep but I expect temps to go up when winds shift
 
ForsythSnow said:
Just noticed we were upgraded to a winter weather advisory here. Not a good sign to come if the NWS is expecting more areas to receive ice. Only expecting up to a tenth of an inch per advisory here.
Click to expand...

That sounds about right, the folks in Upstate SC may be in more trouble. I think this is the first 3km NAM run that gets light icing down to Forsyth County.
 
My wet bulb here in the upstate right now is 28 that's not good. And as the night goes on I'm sure that number will go lower

Sent from my SM-G955U using Tapatalk
 
Here around CAE, looks like the majorty of higher resolution modeling has us right around 35F+ as the precipitation moves in and we eventually make it into the 50's tomorrow. Surely these models aren't going to bust for us. That'd be quite a problem, and we will see come 7AM or so, if moisture starts to stream out ahead. In situations like these, little "fingers" of moisture are possible that modeling does not pick up on.
 
Shawn said:
Here around CAE, looks like the majorty of higher resolution modeling has us right around 35F+ as the precipitation moves in and we eventually make it into the 50's tomorrow. Surely these models aren't going to bust for us. That'd be quite a problem, and we will see come 7AM or so, if moisture starts to stream out ahead. In situations like these, little "fingers" of moisture are possible that modeling does not pick up on.
Click to expand...
I'm sitting at 33 dp 18 thick clouds rolling in
 
ForsythSnow said:
This looks like a fun sleet storm. Either that or there's going to be a ton of ice accretion.
View attachment 3768
Click to expand...

There's no way heavier rates won't release enough latent heat (from liquid turning ti ice, it gives off heat) to keep the surface at 32F. Serious ice storms generally need to be 28-29F or so with heavy precipitation.

Of course, I am just going by that one sounding.
 
Im in royston, GA tonight from Birmingham. Im just south of I-85 on GA/SC line. From my days of growing up in Gainesville,Ga this feels like a CAD Ice event in the making. Models are never right when they show Zr changing to rain. The transition never occurs sometimes.
 
Shawn said:
There's no way heavier rates won't release enough latent heat (from liquid turning ti ice, it gives off heat) to keep the surface at 32F. Serious ice storms generally need to be 28-29F or so with heavy precipitation.

Of course, I am just going by that one sounding.
Click to expand...
So per that, sounds like we would warm up if it sleets, or even if the rain starts to freeze. However, if it gets to 30 or 29 somehow, it would be way worse, but I can't see that happening.
 
ForsythSnow said:
So per that, sounds like we would warm up if it sleets, or even if the rain starts to freeze. However, if it gets to 30 or 29 somehow, it would be way worse, but I can't see that happening.
Click to expand...

Yeah, the scariest thing to see sitting around the temperature of 31-32F is light freezing rain or drizzle for a prologned period of time.
If you get under some of the heavier bands and something screws you, keeping you right at 30F or below, you're in trouble.

Looking at the charts above for the upstate are a bit unsettling, as it's wanting to have that situation happening as you can see in the > 1 " ice accumulation maps. The Canadian suite of modeling does handle CAD better. This isn't an arctic plunge or anything, that it could be way over doing as we usually see from the model.
 
I looked back to February 2015's ice storm and saw that the low track is quite similar to this system's. However, the big difference is that it will be raining morning into afternoon versus day into night.
 
Latest HRRRs have backed off on the more problematic ice scenarios in the Upstate, which is a good thing. RGEM may be on it's own.
 
Yeah these temps don't look promising. Might hit 32 but the wedge should scour out rather quickly. Temps don't support a significant event. RGEM thinks I'm at 31 right now..I'm currently at 35

We rain
 
Okay, cloud clover and winds starting to work their magic. Temperatures up to almost 40 around the area. Whew.
 
Temperature currently at 37

RGEM thinks I'm at 31..lol

Reality starting to set in. Should be one of the coldest rains so far this season. This winter rocks!
 
Shawn said:
Yeah, the scariest thing to see sitting around the temperature of 31-32F is light freezing rain or drizzle for a prologned period of time.
If you get under some of the heavier bands and something screws you, keeping you right at 30F or below, you're in trouble.

Looking at the charts above for the upstate are a bit unsettling, as it's wanting to have that situation happening as you can see in the > 1 " ice accumulation maps. The Canadian suite of modeling does handle CAD better. This isn't an arctic plunge or anything, that it could be way over doing as we usually see from the model.
Click to expand...

Based on my experiences with ZR, sometimes heavier ZR leads to warmer 2 meter temperatures. I wonder if that would likely be due to the heavier rain pulling down warmer temperatures from aloft. Or even if the 2m temps didn't warm, the heavier rain might have still had more trouble accumulating. It seems that the highest ratios of accretion to ZR are often favored with lighter ZR. If for no other reason, think about a higher % of heavier rain dripping off branches too quickly for it to freeze on those branches.

Edited
 
Last edited:
GaWx said:
Based on my experiences with ZR, sometimes heavier ZR leads to warmer 2 meter temperatures. I wonder if that would likely be due to the heavier rain pulling down warmer temperatures from aloft. Or even if the 2m temps didn't warm, the heavier rain might have still had more trouble accumulating. It seems that the highest ratios of accretion to ZR are often favored with lighter ZR.
Click to expand...

As liquid mass turns into ice, it releases heat. Basically think of it as a solid changing to a liquid, the energy "trasnfer" has to give off some sort of warmth. Anything in motion will give off some form of heat.

As the liquid mass freezes on contact, the energy expunged creates a tiny little pocket of heat. As the rates become heavier, more heat is released and eventually the ground level comes above freezing.

Lighter ZR is letting less heat off as fast, because the droplets are smaller or the rate of precipitation as a whole, is lighter. From what I have seen, the bigger ice storms that have occurred in heavy precipitation scenarios were when the surface was too cold (26-28F) to be overcome by the liquid to solid change, and the end result being destructive ice accretion.

At least this process is what I was taught in my reading.

@Webberweather53 will hopefully, have a better response to this process.
 
Last edited:
Shawn said:
As liquid mass turns into ice, it releases heat. Basically think of it as a solid changing to a liquid, the energy "trasnfer" has to give off some sort of warmth. Anything in motion will give off some form of heat.

As the liquid mass freezes on contact, the energy expunged creates a tiny little pocket of heat. As the rates become heavier, more heat is released and eventually the ground level comes above freezing.

Lighter ZR is letting less heat off as fast, because the droplets are smaller or the rate of precipitation as a whole, is lighter. From what I have seen, the bigger ice storms have occurred in heavy precipitation scenarios, when the surface was too cold (26-28F) to be overcome by the liquid to solid change, and the end result being destructive ice accretion.

At least this process is what I was taught in my reading.
Click to expand...

Consider this possible more simplistic reason heavier ZR may tend to accrete on branches at a lower rate: If for no other reason, a higher % of heavier rain likely drips off branches too quickly for it to have time to freeze on those branches. I'll exaggerate to make a point: What if somebody were to rapidly pour a bucket (representing extremely heavy ZR) of supercooled water on a branch? Wouldn't almost all of it go right to the ground below the branch? Compare that to pouring it very slowly over said branch. Wouldn't more of it accrete?
 
As the event is getting pretty close to starting, let me remind you of the 1/3 rule; a nifty way to get an approximation of your wet bulb temperature. First, find your dewpoint depression. This is temperature minus dewpoint. For example, 38F with a dewpoint of 16F gives 38 -16 = 22. Second, take your dewpoint depression and divide it by 3, so 22/3 = 7.3333 degrees. Finally, take your standing temperature and subtract from the value to got above; 38 - 7.3333333 = 30.666 F. Concisely, 1. standing temperature - dewpoint temperature. 2. dewpoint depression divided by 3. 3. standing temperature minus previous value obtained above. Good luck everyone with the event. wetbulb.gif
 
Man what a close call! Currently sitting at 33.4 with a cold cold rain. DP is 29. I don’t think I’ll see 32 though. Wasn’t expecting 33.4 either lol. Hope everyone else in the ice path is warm and safe!


Sent from my iPhone using Tapatalk
 
Dang. 32.5/31 and it’s absolutely pouring like crazy. Wow! Still .5 above freezing though. Radar shows pink over me but it’s all liquid.


Sent from my iPhone using Tapatalk
 
Got lucky here in Dahlonega, got down to 32.2, now it's ticking back upwards slightly with the heavier rain. Can't get much closer than that.
 
32.2/32.2. Just missed ice by .2 degrees although I am sure in the tall pines it’s probably 32. But needless to say it’s pouring in sheets and this is one of the coldest rains I can remember in a while! Beat the forecast low by 3 degrees almost. Already picked up .92”’of rain so far. I couldn’t imagine getting that much in ice...geez!


Sent from my iPhone using Tapatalk
 
You must log in or register to reply here.
Back
Top