I'm right on the line. Should be fun tracking the inward push of warm air into the area. 12 NAM coming in now. It has warmed slightly for RDU (~52 at the warmest point):
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Pattern Dazzling December
- Thread starter Rain Cold
- Start date
12z 3k NAM at the same time (Thursday 21z). A colder look for the Wake County folks.
griteater
Member
A few thoughts on the pattern ahead...
On the EPS, the 1st ridge goes up in the western Aleutian Islands here beginning at hour 24...
At hour 24 when that 1st ridge goes up, the Pacific Jet speed max is along and just off the E Asia coast, and its endpoint is along 180 deg (the Dateline)...
The 2nd ridge goes up in the eastern Gulf of Alaska here beginning at hour 156 (this is the ridge that kicks the SW Canada PV southeast - if modeled correctly)
At hour 156 when that 2nd ridge goes up, the Pac Jet speed max is now located in the western Pacific, and its endpoint is along 160 deg W (Hawaii longitude), which is an optimal location for -EPO / +PNA ridging...
In terms of mechanisms for extending the jet, we have tropical forcing moving east out of the Indian Ocean and toward the W Pac. You can see here how the Pac jet is currently in the process of extending (Dec 9 to Dec 14 shown)...
And this should continue as the tropical forcing moves further east into the W Pac, as seen here...Week 2 for Dec 22-28 is at the bottom...
We also have a significant +EAsiaMtnTorq event that will occur in the next few days as strong high pressure descends into SE Asia. This process will also aid in extending the Pac Jet 1-3 weeks later (i.e. Dec 24 - Jan 14)…
So, going forward, we have mechanisms in place to extend the Pac Jet to a location that fosters -EPO / +PNA ridging.
The fail scenario that I am personally watching for is that the jet eventually overextends and we end up with ridging in the Western and Central U.S. with cold anomalies confined to the far NE and Mid-Atlantic coast (this is what happened in early Jan last year before the jet retracted a bit and the storm hit the SC Upstate well).
The other fail scenario of the Pac Jet not extending enough, and we get troughs dumping into the U.S. West is less likely IMO as we move into Christmas and the 1st week of Jan.
But the broader point goes like this.....
If you are a golfer and you never practice, and you then go out and play, you can't get mad when you don't shoot even par. Same thing applies here....if the Pac Jet has yet to extend, it's not logical to get mad / disappointed for seeing ridging going up out west that isn't in a favorable location for central and eastern U.S. troughing and colder temperatures
On the EPS, the 1st ridge goes up in the western Aleutian Islands here beginning at hour 24...
At hour 24 when that 1st ridge goes up, the Pacific Jet speed max is along and just off the E Asia coast, and its endpoint is along 180 deg (the Dateline)...
The 2nd ridge goes up in the eastern Gulf of Alaska here beginning at hour 156 (this is the ridge that kicks the SW Canada PV southeast - if modeled correctly)
At hour 156 when that 2nd ridge goes up, the Pac Jet speed max is now located in the western Pacific, and its endpoint is along 160 deg W (Hawaii longitude), which is an optimal location for -EPO / +PNA ridging...
In terms of mechanisms for extending the jet, we have tropical forcing moving east out of the Indian Ocean and toward the W Pac. You can see here how the Pac jet is currently in the process of extending (Dec 9 to Dec 14 shown)...
And this should continue as the tropical forcing moves further east into the W Pac, as seen here...Week 2 for Dec 22-28 is at the bottom...
We also have a significant +EAsiaMtnTorq event that will occur in the next few days as strong high pressure descends into SE Asia. This process will also aid in extending the Pac Jet 1-3 weeks later (i.e. Dec 24 - Jan 14)…
So, going forward, we have mechanisms in place to extend the Pac Jet to a location that fosters -EPO / +PNA ridging.
The fail scenario that I am personally watching for is that the jet eventually overextends and we end up with ridging in the Western and Central U.S. with cold anomalies confined to the far NE and Mid-Atlantic coast (this is what happened in early Jan last year before the jet retracted a bit and the storm hit the SC Upstate well).
The other fail scenario of the Pac Jet not extending enough, and we get troughs dumping into the U.S. West is less likely IMO as we move into Christmas and the 1st week of Jan.
But the broader point goes like this.....
If you are a golfer and you never practice, and you then go out and play, you can't get mad when you don't shoot even par. Same thing applies here....if the Pac Jet has yet to extend, it's not logical to get mad / disappointed for seeing ridging going up out west that isn't in a favorable location for central and eastern U.S. troughing and colder temperatures
Last edited:
iGRXY
Member
That's a serious gradient tomorrow. certain locations will be upper 40's while 20 miles away will be in the lower 70's.
Thank you for this. Great breakdown!!A few thoughts on the pattern ahead...
On the EPS, the 1st ridge goes up in the western Aleutian Islands here beginning at hour 24...
At hour 24 when that 1st ridge goes up, the Pacific Jet speed max is along and just off the E Asia coast, and its endpoint is along 180 deg (the Dateline)...
The 2nd ridge goes up in the eastern Gulf of Alaska here beginning at hour 156 (this is the ridge that kicks the SW Canada PV southeast - if modeled correctly)
At hour 156 when that 2nd ridge goes up, the Pac Jet speed max is now located in the western Pacific, and its endpoint is along 160 deg W (Hawaii longitude), which is an optimal location for +EPO / +PNA ridging...
In terms of mechanisms for extending the jet, we have tropical forcing moving east out of the Indian Ocean and toward the W Pac. You can see here how the Pac jet is currently in the process of extending (Dec 9 to Dec 14 shown)...
And this should continue as the tropical forcing moves further east into the W Pac, as seen here...Week 2 for Dec 22-28 is at the bottom...
We also have a significant +EAsiaMtnTorq event that will occur in the next few days as strong high pressure descends into SE Asia. This process will also aid in extending the Pac Jet 1-3 weeks later (i.e. Dec 24 - Jan 7)...
So, going forward, we have mechanisms in place to extend the Pac Jet to a location that fosters -EPO / +PNA ridging.
The fail scenario that I am personally watching for is that the jet eventually overextends and we end up with ridging in the Western and Central U.S. with cold anomalies confined to the far NE and Mid-Atlantic coast (this is what happened in early Jan last year before the jet retracted a bit and the storm hit the SC Upstate well).
The other fail scenario of the Pac Jet not extending enough, and we get troughs dumping into the U.S. West is less likely IMO as we move into Christmas and the 1st week of Jan.
But the broader point goes like this.....
If you are a golfer and you never practice, and you then go out and play, you can't get mad when you don't shoot even par. Same thing applies here....if the Pac Jet has yet to extend, it's not logical to get mad / disappointed for seeing ridging going up out west that isn't in a favorable location for central and eastern U.S. troughing and colder temperatures
The NW trend appears to have commenced. RGEM is next up. Minor deal, but it's all we have for now.
Good.
Ron Burgundy
Member
Really appreciate the effort you put into this - very informative!A few thoughts on the pattern ahead...
On the EPS, the 1st ridge goes up in the western Aleutian Islands here beginning at hour 24...
At hour 24 when that 1st ridge goes up, the Pacific Jet speed max is along and just off the E Asia coast, and its endpoint is along 180 deg (the Dateline)...
The 2nd ridge goes up in the eastern Gulf of Alaska here beginning at hour 156 (this is the ridge that kicks the SW Canada PV southeast - if modeled correctly)
At hour 156 when that 2nd ridge goes up, the Pac Jet speed max is now located in the western Pacific, and its endpoint is along 160 deg W (Hawaii longitude), which is an optimal location for +EPO / +PNA ridging...
In terms of mechanisms for extending the jet, we have tropical forcing moving east out of the Indian Ocean and toward the W Pac. You can see here how the Pac jet is currently in the process of extending (Dec 9 to Dec 14 shown)...
And this should continue as the tropical forcing moves further east into the W Pac, as seen here...Week 2 for Dec 22-28 is at the bottom...
We also have a significant +EAsiaMtnTorq event that will occur in the next few days as strong high pressure descends into SE Asia. This process will also aid in extending the Pac Jet 1-3 weeks later (i.e. Dec 24 - Jan 7)...
So, going forward, we have mechanisms in place to extend the Pac Jet to a location that fosters -EPO / +PNA ridging.
The fail scenario that I am personally watching for is that the jet eventually overextends and we end up with ridging in the Western and Central U.S. with cold anomalies confined to the far NE and Mid-Atlantic coast (this is what happened in early Jan last year before the jet retracted a bit and the storm hit the SC Upstate well).
The other fail scenario of the Pac Jet not extending enough, and we get troughs dumping into the U.S. West is less likely IMO as we move into Christmas and the 1st week of Jan.
But the broader point goes like this.....
If you are a golfer and you never practice, and you then go out and play, you can't get mad when you don't shoot even par. Same thing applies here....if the Pac Jet has yet to extend, it's not logical to get mad / disappointed for seeing ridging going up out west that isn't in a favorable location for central and eastern U.S. troughing and colder temperatures
Good trends closer to go time is key, great to see
iGRXY
Member
I think we have signals out there for a couple timeframes, but as you've seen there's improvement on the models showing up in the day 3-6 range even right now. I have a suspicion that we won't start seeing legit trend run by run storms show up until we are under 150 hours. Hopefully we can land one of these things and as it stands now, there's a legit chance at that over the next 2 weeks.
LukeBarrette
im north of 90% of people on here so yeah
Meteorology Student
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2017-2023 Supporter
Woof bark bark 
LukeBarrette
im north of 90% of people on here so yeah
Meteorology Student
Member
2024 Supporter
2017-2023 Supporter
And a completely different look than the other models in terms of ridging out west.. I’ve always believed as we get closer we will see more of this ridge building out west than the other models are showing right now. (Kind of like the trend we saw last winter) obviously like grit said we don’t want this sliding too far east but at this juncture I like what I see. I expect other models to bring up that ridge with time. 
LukeBarrette
im north of 90% of people on here so yeah
Meteorology Student
Member
2024 Supporter
2017-2023 Supporter
Looks a lot worse boooo
Yeah I’ve never been a fan of this threat .. if anything watch the 20th but even then I’m eh about it
LukeBarrette
im north of 90% of people on here so yeah
Meteorology Student
Member
2024 Supporter
2017-2023 Supporter
Wasting cold air with this…
Yep, good call by Ollie on this one, just a lakes vortex so it has a higher then average chance of shearing out, even tho setups like that have worked in the past, no true cold air with this either
The 18th system has always been more of an N. Ala/N. Ga. hope and a prayer thing. The key player to watch is the Great Lakes vortex's position and orientation. A little further NW opens the door for a little more moisture, but too much and it's just sprinkles.