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Wintry Jan 15-16 Winter Storm Discussion & Obs

Interesting post from ILMRoss over on American making the case that the 18z GFS of not right.
No there's a little truth to that. SLPs want to ride ribbons of low level vorticity, which is the fancy pants way of saying "wind shifts". During CAD wedges, there's an area (typically off the coast) where the NE winds of the wedge butt directly against the SW or SE flowing winds off the coast. This is an area of natural "spin". When upper air energy is close by that spin gets stretched and spins faster (think the common ballerina analogy where it spins faster when the ballerina brings body closer together).

So the GFS has this. I've tried to put in some arrows below showing wind speed and where this "ribbon" exists and where you'd expect the LLC to ride. This is basically why all the mets are flummoxed as to why the GFS wants to barrel this thing up 95.image.png.1f3be307fb7c3b76e2b1ff782282b9f7.png
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Myfrotho704_ said:
One-two fast trends with the cutoff off cali or the more digging with the southern part of the energy and we’re gonna go back to a flatter/sheared look, it’s close View attachment 104061
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Agreed. Regardless of which way it ultimately ends up (amped or flatter), it's a real tightrope until that energy is diving southward and I don't know that this is going to be settled definitively until Thursday evening or Friday when it's actually onshore. I think the ICON solution was a little wonky and probably extreme, but something in-between the ICON and the current op GFS/Euro solutions is probably the most likely scenario based on the current trends.
 
rburrel2 said:
Splitting hairs here but the 18z euro looks slightly more positively tilted compared to the 12z trough. Def more positive tilted than 18z gfs.
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Good to see you in here burrel...just in time with massive CAD moving in!

Here is EPS Mean diff from last run

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mydoortotheworld said:
Webb may argue that the OP GFS may need to be taken seriously despite disagreements with its ensembles, but OP GFS vs GEFS & EPS? Idk chief. I’d like to hear his thoughts on that but I’d put money on EPS every time
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If someone was making me lay down money, you are absolutely right.
 
mydoortotheworld said:
Webb may argue that the OP GFS may need to be taken seriously despite disagreements with its ensembles, but OP GFS vs GEFS & EPS? Idk chief. I’d like to hear his thoughts on that but I’d put money on EPS every time
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The control itched north and that kind of discredits the explanation he made. Personally I’ve seen the GFS erode CAD and drive LP right through CAD for years now. This is exactly what I expect from it in this range.
 
Hypsometric said:
The question basically boils down to: is this a resolution issue or is varying the initial conditions slightly somehow causing this? The fact there are still a handful of members well-inland makes me think it's something to do with the initial conditions.
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Believe you have a solid hypothesis there
 
mydoortotheworld said:
Webb may argue that the OP GFS may need to be taken seriously despite disagreements with its ensembles, but OP GFS vs GEFS & EPS? Idk chief. I’d like to hear his thoughts on that but I’d put money on EPS every time
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If it was the oppsite. GFS off the coast and both sets of ens inland. The GFS op would be thrown out , no questions asked
 
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