Mid to Long Term Discussion 2019

[jjwxman]

NAM’d

[FallsLake]

I've always been a fan of the PNA (...being positive). It seems it has the most effect on the SE for increasing the chance of winter storms. Right now I'm not seeing any solid positive setups. Just lots of weak lows drifting through western Canada (not good). The AO looks to go solidly negative so that will help get some (and keep) cold air over into out hemisphere. We just need a big high pressure to come down through western Canada (with +PNA).  

https://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/teleconnections.shtml

 

[Orangeburgwx]

PNA screws us, no cold in LR on the 6z GFS

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[Tacoma]

10 hours ago, jjwxman said:

NAM’d

Boy what a perfect track of the Gulf Low, where the hell is the cold air when you need it, this weather is boring. 

[NorthHillsWx]

Positivity from early December is turning into reality that (as usual) we punt December and the first week of January. No good source of cold air throughout this period means that even if a storm pops up, it'll rain. Welcome to the South

[ragtop50]

Purely from an educational standpoint (to help me and others learn), why would the below scenario depicted by the NAM not be showing more frozen precip in NC and VA?  We always here a low off/near the coast just to our SE with a HP just to our north is the perfect setup.  I realize the NAM may be off base here (and that it is the NAM at hour 84), but with what it is showing, why is the setup all or mostly rain?  Is it because the HP to the north is not strong or cold enough?

enough?

 

 

[Orangeburgwx]

Purely from an educational standpoint (to help me and others learn), why would the below scenario depicted by the NAM not be showing more frozen precip in NC and VA?  We always here a low off/near the coast just to our SE with a HP just to our north is the perfect setup.  I realize the NAM may be off base here (and that it is the NAM at hour 84), but with what it is showing, why is the setup all or mostly rain?  Is it because the HP to the north is not strong or cold enough?
enough?
 
 

1028HP is super weak, we need a big dog 1040+

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[BullCityWx]

23 minutes ago, ragtop50 said:

Purely from an educational standpoint (to help me and others learn), why would the below scenario depicted by the NAM not be showing more frozen precip in NC and VA?  We always here a low off/near the coast just to our SE with a HP just to our north is the perfect setup.  I realize the NAM may be off base here (and that it is the NAM at hour 84), but with what it is showing, why is the setup all or mostly rain?  Is it because the HP to the north is not strong or cold enough?

enough?

 

 

There’s basically no cold air. That high could be 1040 and it would be marginal. 

[FLweather]

26 minutes ago, ragtop50 said:

Purely from an educational standpoint (to help me and others learn), why would the below scenario depicted by the NAM not be showing more frozen precip in NC and VA?  We always here a low off/near the coast just to our SE with a HP just to our north is the perfect setup.  I realize the NAM may be off base here (and that it is the NAM at hour 84), but with what it is showing, why is the setup all or mostly rain?  Is it because the HP to the north is not strong or cold enough?

enough?

 

 

It's a cut off in the SJT.

Notice the flow out west on the 500mb chart below. 

The northern stream and southern stream are together.  Then it splits.

The northern stream goes into Canada while the southern stream recurves over OK, TX.

There is no northern stream interaction(cold air). So no available cold air source to feed into the storm while the moisture is available. 

 

[CaryWx]

ragtop,

Follow the 558 line (for ex.) as it comes onshore in So. Cal. Arcs up over southern Canada and exits off Maine.  Essentially everything below it is just one big southern ridge of air.  None of that (underneath it) is very cold at all really.   

Now find the 540 line and trace it.  THAT'S the one we need running at or very near our state, but it's hell & gone from the US once it exits the state of Washington.

[NC_WX]

3 hours ago, ragtop50 said:

Purely from an educational standpoint (to help me and others learn), why would the below scenario depicted by the NAM not be showing more frozen precip in NC and VA?  We always here a low off/near the coast just to our SE with a HP just to our north is the perfect setup.  I realize the NAM may be off base here (and that it is the NAM at hour 84), but with what it is showing, why is the setup all or mostly rain?  Is it because the HP to the north is not strong or cold enough?

enough?

 

 

Good question and would add that a common mistake when SE folks are looking for snow is to focus on a high pressure to the north or worse, northeast of the Carolinas as your image progs.  The High we want needs to be northwest near the Great Lakes supplying dry, arctic air.  Too far east and the clockwise winds pull air from the Atlantic which modifies the cold air causing warming aloft.  This is a classic Cold Air Damming setup which rarely produces snow but is classic for frz rain or if the column of air is cold enough, sleet.  I've lost count how many times I've read "CAD" and snow in the same wishcast and it rarely works out.  Carolina big snows come from a Gulf low that exits near Charleston to Savannah and strengthens as it moves up the coast with cold air coming from the NW, not NE.  And sometimes, we get the trailing upper level low to cross the area with it's limited coverage area of snow but for those fortunate enough to get ULL snow, it is the postcard variety with higher ratios but usually is short-lived.  Been tracking Carolina snows since the early 60's and the NW high/SE low is the combination we want for snow....if the high is too far east, no joy.

[jjwxman]

Has anyone cared to notice the Euro is possibly caving to the GFS on it’s northern extent of the moisture? GSO went from 1.3” QPF to 0.1” QPF over the last 3 runs of the Euro.  I just find this intriguing considering the GFS in the past likes to suppress these type of storms only to adjust northward. We’ll see what happens. 

[mackerel_sky]

16 minutes ago, jjwxman said:

Has anyone cared to notice the Euro is possibly caving to the GFS on it’s northern extent of the moisture? GSO went from 1.3” QPF to 0.1” QPF over the last 3 runs of the Euro.  I just find this intriguing considering the GFS in the past likes to suppress these type of storms only to adjust northward. We’ll see what happens. 

GFS hasn’t wavered in the past 4-5 days, with no moisture making it much North of i-20. Rock steady and may be right!

[BIG FROSTY]

10 hours ago, mackerel_sky said:

GFS hasn’t wavered in the past 4-5 days, with no moisture making it much North of i-20. Rock steady and may be right!

I just hope the rain stays south of me! It is awful wet around here. IF NO snow I would like to stay dry for a week or so.

[Southern Track]

Thought I'd screenshot this before it disappears tomorrow:

[franklin NCwx]

Improvements at the end of the ensembles

[mackerel_sky]

All good looking patterns stay at the end of model runs, op, ensembles, and seasonal! They never seem to move forward in time, unless they are warm! Looking toasty around Christmas, mid-upper 60s here

[LurkerBoy]

Officially no CAD for Christmas. Bummer 

[Upstate Tiger]

Too bad this weekends system isn’t 24 hours faster with some NS interaction.  Pretty cold the last couple of days here.  21 degrees in Cherryville this morning. 

[griteater]

15 hours ago, NC_WX said:

Good question and would add that a common mistake when SE folks are looking for snow is to focus on a high pressure to the north or worse, northeast of the Carolinas as your image progs.  The High we want needs to be northwest near the Great Lakes supplying dry, arctic air.  Too far east and the clockwise winds pull air from the Atlantic which modifies the cold air causing warming aloft.  This is a classic Cold Air Damming setup which rarely produces snow but is classic for frz rain or if the column of air is cold enough, sleet.  I've lost count how many times I've read "CAD" and snow in the same wishcast and it rarely works out.  Carolina big snows come from a Gulf low that exits near Charleston to Savannah and strengthens as it moves up the coast with cold air coming from the NW, not NE.  And sometimes, we get the trailing upper level low to cross the area with it's limited coverage area of snow but for those fortunate enough to get ULL snow, it is the postcard variety with higher ratios but usually is short-lived.  Been tracking Carolina snows since the early 60's and the NW high/SE low is the combination we want for snow....if the high is too far east, no joy.

It depends on the setup.  If talking about CAD with a retreating cold air mass, then yes, that's a setup for ice.  But ideally for snow, we want to see high pressure in all directions to the north (NW, N, NNE - "banana high").  CAD can be critical for those along the precip type transition line (I-85) in terms of driving cold air in the lower levels farther to the south.  2 of the all-time great cold snowstorms for parts of the southeast had big time CAD signatures, Feb 1979 and Jan 1988

 

[yotaman]

3 hours ago, LurkerBoy said:

Officially no CAD for Christmas. Bummer 

60's once again for Christmas. 

[franklin NCwx]

Gefs looks good starting around day 10. Let's see if that continues!

[CaryWx]

1 hour ago, yotaman said:

60's once again for Christmas. 

Yeah I wasn’t debbie downing the other day when I mentioned 60s for Christmas

[BooneWX]

Shorts at Christmas. A tradition unlike any other!

[LurkerBoy]

I’m from NY originally. How common is U50s/60s on Xmas in these parts?

[Orangeburgwx]

I’m from NY originally. How common is U50s/60s on Xmas in these parts?

Yearly tradition

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[BullCityWx]

6 hours ago, Upstate Tiger said:

Too bad this weekends system isn’t 24 hours faster with some NS interaction.  Pretty cold the last couple of days here.  21 degrees in Cherryville this morning. 

That was one heavy frost today 

[mackerel_sky]

5 hours ago, griteater said:

It depends on the setup.  If talking about CAD with a retreating cold air mass, then yes, that's a setup for ice.  But ideally for snow, we want to see high pressure in all directions to the north (NW, N, NNE - "banana high").  CAD can be critical for those along the precip type transition line (I-85) in terms of driving cold air in the lower levels farther to the south.  2 of the all-time great cold snowstorms for parts of the southeast had big time CAD signatures, Feb 1979 and Jan 1988

 

It’s actually amazing at how much these storms were identical, not in outcome, but exact same low placement and strength and both had the pressure at 1036 around NC! Crazy

[Orangeburgwx]

It depends on the setup.  If talking about CAD with a retreating cold air mass, then yes, that's a setup for ice.  But ideally for snow, we want to see high pressure in all directions to the north (NW, N, NNE - "banana high").  CAD can be critical for those along the precip type transition line (I-85) in terms of driving cold air in the lower levels farther to the south.  2 of the all-time great cold snowstorms for parts of the southeast had big time CAD signatures, Feb 1979 and Jan 1988

 

Hey Grit, what was the set up for the 73 surface map? A CAD, Miller A, or a rare "perfect storm" of conditions?

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[Grayman]

Who will be the first one to Get suckered in by the hour 366 GFS? Wait I just posted so that’s me. I will never learn to stop looking at fantasy snow. It’s the only kind I get