Mid to Long Range Discussion ~ 2024

[StantonParkHoya]

Meh. RDU always gets cold press to quasi nor’easter bombs that produce 17 inches. I’d like to see the next model offering….

[BooneWX]

16 minutes ago, wncsnow said:

That trough needs to be further west or it's cold, dry and windy for most of the SE. 

this is my fear as well. We did this dance in the front half of Dec. To our benefit this time around, it looks like we could have some blocking to help slow down the progressiveness of the storms.
 

Then again, when is the pattern ever a total slam dunk when we score? Feeling oddly good compared to years past… Don’t know why. I can’t put my finger on it, just do. Hope I’m right.

[Leesville Wx Hawk]

Meh. RDU always gets cold press to quasi nor’easter bombs that produce 17 inches. I’d like to see the next model offering….

It’s old hat by now.


.

[Daniel Boone]

33 minutes ago, wncsnow said:

That trough needs to be further west or it's cold, dry and windy for most of the SE. 

Blocking, if realized should help force Trough further West. If not it should allow for NS Vorts to dive further South so, should get some chances for Snow one way or the other.

[GaWx]

1 hour ago, wncsnow said:

That trough needs to be further west or it's cold, dry and windy for most of the SE. 

 A split flow (more frequent in El Niño) is often the best bet to get significant wintry precip for much of the SE, including the deep SE (see image below for a deep SE modeled example):

-Having the N stream to the north of one’s latitude with the trough axis nearby or to the east (it’s actually well to the east in the image below) allows for ample supply of cold at low levels 

-Having the S stream near or a little south of one’s latitude with its trough axis to the west allows for moist WSW or SW flow bringing the Gulf moisture/warmth above the low level cold

A textbook modeled split flow: note the N stream with cold WNW flow well to the north (trough axis to the east) while at same time there’s S stream with moist WSW flow nearby bringing in ample moisture (trough axis to the west). The precip map for this showed snow on the northern fringes in the deep SE:

 

Edit: These are not easy to achieve as one could imagine (delicate setup), probably moreso when not in El Niño. These are often not going to be seen on ensemble means out more than a few days and they often appear for only a short period.

[GaWx]

 This is about the coldest 12 run CFS ens map I can recall ever seeing for the SE for a full week not starting for 2 weeks meaning a very strong cold signal for the start of the period being 2 weeks out: this has 5-6F BN over almost all of the SE! Remember that this is 12 runs of a 4 member ensemble and is actually likely underdone, if anything, due to smoothing.

 

Precip averages 0.25” BN, which for such a cold period is actually decent since strong cold is more often than not dry. That would still be 0.5-1” of qpf for most.

[WinstonSalemArlington]

From Mike Thomas, Fox 5 DC:

[wncsnow]

The upcoming pattern looks similar to the one we had in early December.. not a snow pattern.  

[suzook]

27 minutes ago, wncsnow said:

The upcoming pattern looks similar to the one we had in early December.. not a snow pattern.  

I was thinking the same thing. Just gonna be a cold blast with zero precip unfortunately. But I guess, just getting the cold in place is the 1st step in the right direction.

[olafminesaw]

19 minutes ago, wncsnow said:

The upcoming pattern looks similar to the one we had in early December.. not a snow pattern.  

The AO is forecast to be -2 vs-1 in early Dec. NAO about the same at -.5. PNA +.5 vs +1  in Dec. So about the same, although AO is probably the biggest driver for snow and -2 is substantial. It would be the most negative AO since 2022. The last time a -2 AO or more was coupled with + PNA and -NAO was January 2021 which was near normal temps and snowfall

[olafminesaw]

[StantonParkHoya]

52 minutes ago, wncsnow said:

The upcoming pattern looks similar to the one we had in early December.. not a snow pattern.  

Actually kind of a snow pattern for the immediate coast of NC

[suzook]

Everyone here can thank me for the cold, and snow in January, as my inground pool dig starts Jan6th

[NorthHillsWx]

I’m not seeing what others are noting on the ensembles in regards to moisture availability. Everything looks exceptionally dry if you take out the rain from the 2-4th period. So once the cold follows that system there is a very strong signal for it to be very dry. Maybe someone could show me the opposite but I don’t see anything but dry cold following that system 

[wncsnow]

1 hour ago, StantonParkHoya said:

Actually kind of a snow pattern for the immediate coast of NC

Perhaps the outer banks 

[StantonParkHoya]

53 minutes ago, NorthHillsWx said:

I’m not seeing what others are noting on the ensembles in regards to moisture availability. Everything looks exceptionally dry if you take out the rain from the 2-4th period. So once the cold follows that system there is a very strong signal for it to be very dry. Maybe someone could show me the opposite but I don’t see anything but dry cold following that system 

When was the last time we had a clipper? Seems like 20 years

[suzook]

19 minutes ago, StantonParkHoya said:

When was the last time we had a clipper? Seems like 20 years

I am new to the south, didn't realize we could get a clipper down here. They used to overperform most times in the NE.

[tarheelwx]

95% of the clippers east of the mountains don’t produce any snow.  Once in a while we pull a rabbit out of the hat and get usually an inch or less. 
TW

[olafminesaw]

41 minutes ago, StantonParkHoya said:

When was the last time we had a clipper? Seems like 20 years

This month 

[BooneWX]

https://x.com/wxbrad/status/1872313028605317276?s=46
 

this is borderline bullish for him

[Upstate Tiger]

Looking at the 12z GFS, the 7th - 9th appears to be our best opportunity for a SE winter storm over the next 2 weeks.  Just need a bit of blocking and we’re in business.  

[NC_hailstorm]

That ridging out west is strong and persistent,I even seen a few frames hitting 591dm that's close to death ridge stuff you see in the summertime.

[NC_hailstorm]

Euro and the Canadian are further east with the trough at day 7 while the GFS,ICON,and UK are further west.

Somewhere in the middle might work but a tick west would be better to give these shortwaves more room to dig.

[wncsnow]

The Euro trough is not what you want to see for snow. Way too far NE. 

[GaWx]

15 minutes ago, wncsnow said:

The Euro trough is not what you want to see for snow. Way too far NE. 

Are you talking about the Euro operational trough or the Euro ensemble mean trough? Also, what forecast days/hours are you referring to?

[wncsnow]

5 minutes ago, GaWx said:

Are you talking about the Euro operational trough or the Euro ensemble mean trough? Also, what forecast days/hours are you referring to?

The operational. From hour 150 on really. It might be setting up for something better after 16 days if we can get a 50/50 low to setup in the NE

[GaWx]

2 hours ago, wncsnow said:

The operational. From hour 150 on really. It might be setting up for something better after 16 days if we can get a 50/50 low to setup in the NE

1. Thanks. But operationals are almost always jumpy at 240+. So, I put little importance on operationals days 10+, when I prefer ensemble means.

2. So, looking at 12Z Euro/GFS/CMC ens means, the trof is ~80W/near our longitude.

3. Would it be too dry for the SE to get a synoptic scale winter storm with the mean trof near 80W? I’d say yes in many cases, especially when there’s just the N stream keeping it dry. I’d then prefer it be ~90W.  However, an often hard to prog (more than a few days out on models) short-wave induced split flow underneath the N stream would be a way to make it moist while the N stream to the north keeps the cold air in place at the sfc.

4. Here are 9 examples of moist split flow just in advance of SE winter storms even with the N trof even further east in all but one case:

12/8/18: (El Niño) N trof 72W but WSW flow SE

 

12/8/17: (La Nina) N trof 85W but SW flow SE

1/21/16: (El Niño) N trof 70W but WSW flow SE

 

2/25/15: (El Niño) N trof 77W but WSW flow SE

1/9/11: (La Nina) N trof 70W but incoming SW flow underneath

 

2/11/10: (El Niño) N trof 65W but incoming WSW to SW flow underneath

 

1/29/10: (El Niño) N trof 70W but incoming SW flow underneath

 

2/25/04: (warm neutral) N trof 70W but SW flow SE

1/9/04: (warm neutral) N trof 60W but WSW flow SE

 

5. Could there be a shortwave induced moist split flow underneath the progged 10-15+ day +PNA induced cold mean E trof coming that can’t yet be seen on ens H5 means? It’s very possible. Would I bet on it? No because we’re in La Nina, when it is more difficult to get a split flow. If this were El Niño with a frequent moist S stream, I’d be more excited. Regardless, sometimes these occur during La Nina like in 2 cases posted above, 12/8/17 and 1/9/11. Also, the progged couple of week long cold dominated period as opposed to just one and done helps. Plus there are obviously other ways to get a winter storm. So, keep hope alive, folks!

[WinstonSalemArlington]

[WinstonSalemArlington]

[StantonParkHoya]

8 hours ago, suzook said:

I am new to the south, didn't realize we could get a clipper down here. They used to overperform most times in the NE.

You really need the Manitoba Mauler to have fun