Ice Time? Dec. 16ish Possible CAD Event

[Tar Heel Snow]

I figured I might as well fire up the thread just in time for the 12z Euro! Get your chainsaws ready, and let’s see what the first real track of winter brings us!

[wncsnow]

Well the Euro is still the warmest model probably and shows it going over to rain for most 

[jjwxman]

The Euro remains the least impressive on the CAD setup. WAA overwhelms the CAD very quickly for all of NC.  CLT and Upstate SC never even gets in the game and even GSO is on the edge. At this point it’s definitely a plausible outcome, but I’m not so sure the Euro has a good handle on the CAD.

[magpiemaniac]

I’m feeling pretty confident that the north half of Triad will see something wintry.  Type and how much remains to be seen, but we’re going to have the surface temps here for at least some ice.

[Jonathan]

Man, the EURO op is just not impressed at all.

[BooneWX]

Imo, Globals struggle with CAD. Tomorrow will be telling with the NAM firmly in range, even though it’ll tend to over do the cad slightly.

[wncsnow]

Where's lookout he is very knowledgeable with CAD events 

[CAD_Wedge_NC]

6 minutes ago, BooneWX said:

Imo, Globals struggle with CAD. Tomorrow will be telling with the NAM firmly in range, even though it’ll tend to over do the cad slightly.

I have to agree here. History would tell you that the CMC is better in these situations while the Euro doesn't handle the Cad as well.... I would not get too concerned about the Euro in this instance. As a side note, once we get into NAM range, it will tell us all we need to know about the thermal structure.

[burrel2]

One negative about this event is there’s no extremely dry surface air to start. A lot of times the cad over performs due to under modeling of how dry the preceding air mass is. That won’t be much of a factor for this storm. 
 

 

[SnowNiner]

8 minutes ago, burrel2 said:

One negative about this event is there’s no extremely dry surface air to start. A lot of times the cad over performs due to under modeling of how dry the preceding air mass is. That won’t be much of a factor for this storm. 
 

 

 

I agree. Dew points for the Carolinas in the 20s does not seem like we cool that much. That plus the EPS backing off on the strength of the 50/50 makes me think this is a classic north of I40 situation for anything noteworthy. 

[wncsnow]

Take it for what its worth but at the end of the 18z nam it does not look impressive with the CAD. 

[Blue_Ridge_Escarpment]

4 minutes ago, wncsnow said:

Take it for what its worth but at the end of the 18z nam it does not look impressive with the CAD. 

Mid 20s here at hour 84

[griteater]

3 minutes ago, SnowNiner said:

I agree. Dew points for the Carolinas in the 20s does not seem like we cool that much. That plus the EPS backing off on the strength of the 50/50 makes me think this is a classic north of I40 situation for anything noteworthy. 

Sounds about right, but we'll see how this trends going forward.

In terms of the modeling, the CMC is good at getting early hints at CAD, but it's typically too cold.  Euro is probably a little too warm.  The high res models will be on the colder side I'm sure.  50/50 low needs to escape to the NE slower to see this get colder

[griteater]

Thoughts from GSP NWS

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 200 PM Saturday...The latest op models depict another dynamic
system will affect the fcst area Tue night into Wed. A coupled jet
will develop across the the Deep South late Tue and create very good
upper div, while a stg h5 trof develops a broad and highly moist sfc
low progged to cross the area thru the day Wed. Ahead of this
system, a developing classical CAD looks to be in place as a 1035 mb
sfc high is maintained across se/rn Canada. This pattern will
potentially set the stage for wintry mix precip generally along and
north of the I-85 corridor beginning aft 00z Wed.

As WAA flow increases abv 2 kft, a warm nose will work north and
melt the snow thru a deep layer as seen up to 8 kft on the latest
soundings. With the sfc layer remaining cold and reinforced with
cooler td/s, the rain is anticipated to change over to -fzra then
eventually a sleet mix after 08z while sfc temps drop to sub-freezing
wet bulbs east of I-26 and north of I-85. Ice accums look low-end
currently as the system will be relatively short lived and the
-fzra shud mix with -ra early on. Across the NC mtns and higher
 elevations of the Upstate and NE GA, snow will be the main
 p-type, where a few inches are possible across the srn
 escarpment and lower totals to the north. A lot can change with
 this system and the fcst will be adjusted over the next few
 days. One to keep an eye on.

[SnowNiner]

11 minutes ago, griteater said:

Sounds about right, but we'll see how this trends going forward.

In terms of the modeling, the CMC is good at getting early hints at CAD, but it's typically too cold.  Euro is probably a little too warm.  The high res models will be on the colder side I'm sure.  50/50 low needs to escape to the NE slower to see this get colder

You would think this decent -NAO we finally have on our side right now would work some magic and keep the 50/50 more in place. Perhaps it can do work, we'll see. 

[BornAgain13]

26 minutes ago, wncsnow said:

Take it for what its worth but at the end of the 18z nam it does not look impressive with the CAD. 

Look at that 1035 straight north... its in a great position , pumping cold air down , perfect setup for ICE 

[griteater]

18 minutes ago, SnowNiner said:

You would think this decent -NAO we finally have on our side right now would work some magic and keep the 50/50 more in place. Perhaps it can do work, we'll see. 

The -AO/-NAO are helping here, but for our region, ideally those reds over Greenland (positive anomalies) would be farther S/SW

[BooneWX]

GFS sticks to its guns 

[magpiemaniac]

18z GFS cuts the ice in half compared to previous run IMBY.

[SnowNiner]

40 minutes ago, griteater said:

The -AO/-NAO are helping here, but for our region, ideally those reds over Greenland (positive anomalies) would be farther S/SW

Agreed, I'd love to have the high pressure in NY and not Canada. Beggers/choosers whatnot, but I'm happy to have some tracking in December. If we keep the -AO/-NAO regime into January I think we score eventually. 

[Jonathan]

18Z GFS keeps the low over land. Destroys the CAD. Barrelling right through the HP, even with a stout HP, a 50/50 low and a -NAO/-AO regime. Literally the best set of ingredients we've had since 2009-2010.

Like what do we have to do? 

[jjwxman]

41 minutes ago, magpiemaniac said:

18z GFS cuts the ice in half compared to previous run IMBY.

Same here in the Triad. 

[BornAgain13]

I still get almost 1/2" of ice per 18 GFS

[griteater]

NAM was a touch better with the 50/50 low this run.  Here's the 12km precip type on the last frame Wed morning at 7AM

[griteater]

NAM Temperature and Dewpoint at 7AM Wed

[wncsnow]

Yea the NAM has temps here in the upper 20s so it would get dicey with ice. 

[buckeyefan1]

7 minutes ago, griteater said:

NAM was a touch better with the 50/50 low this run.  Here's the 12km precip type on the last frame Wed morning at 7AM

Still looking icy I see. The next few days will be interesting to see how well the models play ‘catch up with the cad’ 

[griteater]

Big warm nose here at Hickory of +5.0C at 800mb.  Says sleet, but this would be freezing rain.  Sleet to the west.

[wncsnow]

2 minutes ago, griteater said:

Big warm nose here at Hickory of +5.0C at 800mb.  Says sleet, but this would be freezing rain.  Sleet to the west.

I'm hoping for more sleet than ZR here near Marion and thats usually the case here in these setups but thats quite the warm nose

[BullCityWx]

925 is -4C at KHKY. I wonder if that keeps them with IP.