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February Medium/Long Range Disco Thread 2


WxUSAF

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18 minutes ago, Thanatos_I_Am said:

Bob, when you get a chance, can you explain why the Euro doesn't get any precious up our way for that Day 8 threat? When you look at the MSLP maps it looks like that SLP is in a great spot. 

I'm not Bob but when i look at the upper level maps the steering flow at 168 hr is more E-W oriented over the EC which means(to me) that any precip will get shunted off to the east before it can climb.  By the time the upper low gets into a good spot the surface low is too far off the coast.  The timing for the two look to be off.  But this is trying to glean things from the 24hr panels.

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1 hour ago, Thanatos_I_Am said:

Bob, when you get a chance, can you explain why the Euro doesn't get any precious up our way for that Day 8 threat? When you look at the MSLP maps it looks like that SLP is in a great spot. 

Also not Bob but from a quick look at the h5 and mslp the problem I see, as Bob has pointed out, is how the stj system and the northern branch are out of phase.  Its too far out to worry and we have seen plenty of runs that show a good outcome so I am not worrying about this yet but it is how this could go wrong.  On the euro the northern branch sends a system across in tandem with the STJ.  What we really want is the STJ system to be a little out ahead of any northern system, that then allows the stj to turn the corner out ahead of the trough axis and then if the northern branch digs enough it pulls into the system and they phase.  The real simple explanation is you want to see one consolidated center of low pressure with high pressure to its north.  Multiple lows on the playing field to interfere with the flow and moisture transport to develop a healthy precip shield. 

This is the euro, now imagine there was a high pressure where the low over the lakes is.  The flow around the high is perfect not just to keep the cold in, but also to create convergence and lift and enhance the frontogenetic forces along the baroclinic zone.  Basically the circulation coming together between the high and the low creates a zone of lift.  THe circulation also helps the low to develop a closed circulation and aid in moisture transport to the left of the low track.  (wrap around). 

lift.png

 

Now look at the circulation that the euro actually shows and you can see the problem.  No convergence, no lift, lack of precip, and no closed circulation so no wrap around. 

nolift.png

 

Finally this is 24 hours later, and shows why miller b storms often screw us over.  We are further inland then the other coastal cities.  When a storm secondaries it typically transfers to just off the coast where the baroclinic zone often is during the winter.  (temp contrast between colder land and warmer water).  Being further inland we need a healthy moisture transport to the west of the low.  As soon as the secondary takes over the moisture transport to the old primary low is cut off and the precip starts to die.  The moisture transport to the west of the new secondary, though, is disrupted by the left over circulation of the primary inland low.  This is why the miller b often has a tighter precip shield and dry slot develops inland initially until the old primary dies and allows the secondary to develop a mature CCB (cold conveyor belt precip shield) just in time to blast places to our northeast.  This here is still way too far northeast even for that scenario but just imagine the secondary is tucked in off VA beach and the primary is over WV...same problem. 

nolift2.png

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3 hours ago, Thanatos_I_Am said:

Bob, when you get a chance, can you explain why the Euro doesn't get any precious up our way for that Day 8 threat? When you look at the MSLP maps it looks like that SLP is in a great spot. 

PSU's response is absolutely perfect. 

I looked through the eps members. Unfortunately, far too many have the NS low screwing things up. Very few phases in the mix. The best hits don't have the northern stream low and have high pressure moving across. This scenario is perfectly illustrated by PSU's response. 

There are 3 basic scenarios right now that could give us snow

1. Phased bomb with the northern stream (least likely attm)

2. Some sort of convoluted dance between the lows that gives us "something" (most likely if we get any snow at all)

3. Northern stream low gets out of the way or doesn't exist and we get a more classic miller A storm (sacrifice chickens and stuff and hope this happens)

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5 minutes ago, stormtracker said:

Well now that we're screwed with this upcoming storm, might as well camp back in here to talk about our next screwing. 

Well, I only gave it a quick look but the ops 12Z GFS looks pretty "meh", as in the storm is well south.  That said, the system is still there in general, but too far south to phase much.  I didn't care for the look in the later time periods, but again, it's a deterministic model.  The GEFS mean looked better to me.

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1 minute ago, Always in Zugzwang said:

Well, I only gave it a quick look but the ops 12Z GFS looks pretty "meh", as in the storm is well south.  That said, the system is still there in general, but too far south to phase much.  I didn't care for the look in the later time periods, but again, it's a deterministic model.  The GEFS mean looked better to me.

This storm now was squashed to nothing off the SE coast 4 days ago.... just sayin

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1 minute ago, psuhoffman said:

This storm now was squashed to nothing off the SE coast 4 days ago.... just sayin

thats what I was just thinking.  With new pattern establishing itself, i'd think mild/wild swings on Op runs is to be par for the course in the short term.

Nut

 

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2 minutes ago, psuhoffman said:

This storm now was squashed to nothing off the SE coast 4 days ago.... just sayin

Oh, I know.  I was just reporting what the current 12Z ops GFS shows for our next hope.  Right now, I think the key is that there's something still there that has potential.  Have not seen individual GEFS members, but I thought the overall pattern look of the GEFS mean was not half bad.

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18 minutes ago, Maestrobjwa said:

Smh (I see the tear has returned, lol) The 12z GFS is already tryingto take it away (showing a complete OTS to the south). Just one run, though...so we'll see.

I saw that..I'm going to see what the Euro has.  I'll still hang in there for a long while though, it's 8 days away, plenty of time for this to screw us even better.  

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3 minutes ago, pasnownut said:

if it were about 500+ miles closer to Greenland....Yes ;)

Could help for the storm, but likely transient.  Would need to look at later panels.

Nut

 

 

*shamefully hides in corner for geography fail*

I believe I was thinking about the global panel in terms of where Greenland was, lol But hopefully we can establish something on future runs...

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We need to lose the low to the north moving across in tandem with the southern energy. Even if the precip made it here on the 12z euro, the return flow with the low to the north screws up the surface in advance. Midlevels are ok but Like PSU showed earlier, we need a hp (even a weak one) to the north to feed everything.  

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2 minutes ago, Bob Chill said:

We need to lose the low to the north moving across in tandem with the southern energy. Even if the precip made it here on the 12z euro, the return flow with the low to the north screws up the surface in advance. Midlevels are ok but Like PSU showed earlier, we need a hp (even a weak one) to the north to feed everything.  

Maestro...see above for further explanation.  Like I said H good up there but if it moves out and an L replaces it...flow goes to poop and erodes the cold. 

Nut 

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17 minutes ago, Bob Chill said:

We need to lose the low to the north moving across in tandem with the southern energy. Even if the precip made it here on the 12z euro, the return flow with the low to the north screws up the surface in advance. Midlevels are ok but Like PSU showed earlier, we need a hp (even a weak one) to the north to feed everything.  

If it does go down that way we end up with a vortex sitting under the GL ridge close to the 50-50 position. All set up for the next one!

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