Wintry Jan 15-16 Winter Storm Discussion & Obs

[Snowflowxxl]

The HRW are always 3-4 degrees too cold. The trash can is where the belong

 

[Broken024]

No I know they’re cold biased but always interesting to look at. They usually do well with temp profiles when you get really close to the event

Eh. They are usually the last ones showing snow for me. And it ends up not snowing. False hope up the last minute.

 

[tucker]

Chattanooga could very well see snow to the West, South, North, and East of it... Sad times.

 

[ATLwxfan]

Don't fall for it. These WRF models are a trap. Every single time.

Every model is a trap if it pumps out something ridiculous. In general I have seen this model do a decent job with the CAD. But we shall see.


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[MichaelJ]

I know a lot of you know this but I would not put a lot of confidence in the 12Km NAM and start relying on ther 3K NAM from here on in, the resolution of the 3K is worlds better and zeros in better.

 

[weatherfide]

I beg your pardon?! View attachment 105430View attachment 105431

Also, it's showing east winds, sustained around 20 knots around Atlanta, I'm sure with higher gusts. This is a disaster if you like power.

 

[Snowflowxxl]

RGEM was a tick warmer but mostly the same as 6z

 

[NCHighCountryWX]

That’s just not true at all. It’s way more than 4

We took it from the weatherbell maps for any one spot outside of the mountains

The one hour precipitation maps were used

 

[Shawn]

As of 12z guidance (besides Euro) seems 0.25 - 0.5 of actual ice accumulation looks like a good bet for CAE. Ouch.

 

[Faco Thomas]

Well this would be quite bad. Basically a disaster waiting to happen. Heavy Icing with temperatures in the 20s throughout the I-20 areas in SC and GA? The saving grace is that no other models show this. However this shows that I-20 areas in far west SC/GA are not out of the danger zone for major icing just yet. We need to watch over the next 24-36 if other models trend towards the much colder solution that the HRW WRF-ARW model shows

 

[chapelhillwx]

I will eat my hat if it is 18 degrees at GSP and 24 at ATL at 12z Sunday like the WRF-ARW shows. Still even if it's a few degrees too cold, could be sniffing out that the CAD will be stronger than we thought.

 

[Wild Weather Monger]

For the N. Georgia area ice crazies (me), if ever surface temps were to verify a little colder than modeled it would happen on a strong NE wind. 20mph with gusts to 35+ qualifies and at least that part seems rock solid.

 

[Nerman]

RDPS

 

[SouthGarnerSleet]

These FRAM maps are even intimidating and the account for runoff/temps/rates View attachment 105427View attachment 105428

So the 4-6k foot elevations of NC are getting an ice storm now? yeah... no. I dont buy this one bit.

Also, this will be a steady to heavy rain = these totals are wayyy overdone.

 

[Chazwin]

Imo, it's looking more likely that CLT and the immediate NW burbs are gonna be saved by sleet, even the WPC seems to have the worst of the ZR just south and east of CLT.

I agree with this. If I had to put money on it, I would say that eastern York and Lancaster Counties in SC and then going NE from there in Anson County, NC will have the longest duration of ZR and the heaviest accrual. Just N and W in Union and western Stanly counties and west if there, still some ZR… .1-.25” with sleet being the dominant precip and a good bit of it

 

[weatherfide]

I will eat my hat if it is 18 degrees at GSP and 24 at ATL at 12z Sunday like the WRF-ARW shows. Still even if it's a few degrees too cold, could be sniffing out that the CAD will be stronger than we thought.

Yes, that's what I'm concerned about. Even if you adjust it up 3 degrees, it's still 29 to 30 and icing up. Add the winds, which all of the models are showing, and we have power concerns. the NAM 3km wind gusts are really starting to concern me. I'd rather this stay rain and not add extra weight to the trees. I lost power on that last storm due to high winds alone.

 

[griteater]

I documented all the qpf outputs for models and all the latest where above1.0 except ukmet was down to .9.
You are correct, just 30 hours ago they all where 1.5-2.0 heer in the Triad and uniform back to the ridge line

My expierence with transfers is we always end up less than modeled qpf. I'll be suprised with more than .75 qpf north of 40 from Asheville to Burlington

I think there are a few things that will help precip wise in this case:

1. Low transfer occurs in Bama as opposed to E TN
2. Wave is going negative tilt
3. Strong and closed 850mb low is oriented in such a manner that the typically reliable overrunning forcing builds in nicely (seen here)

Of course, all of those things are a net negative with respect to temperatures aloft (warming)

 

[Chazwin]

I will eat my hat if it is 18 degrees at GSP and 24 at ATL at 12z Sunday like the WRF-ARW shows. Still even if it's a few degrees too cold, could be sniffing out that the CAD will be stronger than we thought.

I mean even if it’s running around 4 degrees too cold, you’re still talking about mid 20s with precipitation

 

[tucker]

Question for someone smarter than me: At what point do we look at radar returns vs what's modeled (HRRR)?

I assume this will help with nowcasting, but the returns do look to have a larger precip shield.

 

[SouthGarnerSleet]

I mean even if it’s running around 4 degrees too cold, you’re still talking about mid 20s with precipitation

I've seen temps like this not come close to verifying on this model. Just use the more accurate models for temps.