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Significant Ocean Storm March 5-7 2013 Discussion Part II


earthlight

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Im pretty sure it's an inverted trough feature. Not a narrow norlun trough. Same type of thing that dropped a widespread 3"-9" on SNE a couple weeks back.

 

If it were just a narrow norlun trough, I wouldnt even mention it at all.

I could see how it happens, but again that goes to the complex interaction of the northern stream vort(s) with the main upper low. It could easily interact differently tomorrow and either not exist or exist somewhere else. There's really no model that has gotten this correct so far and it's impossible to hone in on one now.

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Yes..Im watching this one even before the EURO showed us the 2+ last week and everyone started getting interested in it. I think this is our last chance for this season. 

Yeah, it was a promising setup, the end result is yet to be determined, after this week though climo pretty much denies snow except for a flukey storm ala 82, 96(kinda)97, 03.

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Speaking of models- there are plethoras of issues that go into them. One big one is that these variables change over time as well, therefore, though they don't change drastically a small scale change yields huge differences (ie Japan earthquake changed earth axis ever so slightly, etc). Take now for example a miscalculation related to these changes, lets say a burst of energy now happens 10 miles W of where it is supposed to and is one magnitude stringer than expected. This would drastically chang LP placement, strength and more, ie small scale convenctive feedback. Its the same as if an airliner was off a quarter degree when it turned, hours later , if not corrected, it would be hundreds of miles off course. What I am getting at, is that models, especially in this set up will have exceedingly hard times making predictions and to bash then without any analysis as to why its showing th solution it is, is foolish

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It's the same inverted trough that's enhancing New England's precip. But that shortwave coming down greatly enhances it and helps to drag it southwest. Not impossible. It's not some narrow norlun trough. 

 

But potentially having to ditch that coastal really sucks. I never completely give up on events, but things aren't looking great right now. 

As soon as I kept seeing the dual-QPF maxes and the main upper low start trending south I had a sinking feeling we could be in a sucker hole here and sure enough, it's still trending south and the heavy precip keeps getting shunted more and more. I'm still a little hopeful that this is overdone and we see some of it come back later tonight but the trends aren't encouraging, that's for sure.

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Upton

Storm Tracks

Model Forecasts Converging on a Track a Bit Further South (European
and Global Forecast System Compromise)
-
Strong Winds
-
Slightly Colder
-
Precipitation Type Mainly Wet Snow
-
Precipitation Amounts Lower
-
Narrow Bands of Heavy Wet Snow Mainly Wed. Night

Complication
-
Models Show Offshore Low Merging with Upper Level Energy
Causing Pro
-
longed Period of Light Snow Late Thu.

Early Fri.



http://www.erh.noaa.gov/okx/FB_Briefings/WxBriefing_FB.pdf
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As soon as I kept seeing the dual-QPF maxes and the main upper low start trending south I had a sinking feeling we could be in a sucker hole here and sure enough, it's still trending south and the heavy precip keeps getting shunted more and more. I'm still a little hopeful that this is overdone and we see some of it come back later tonight but the trends aren't encouraging, that's for sure.

That can and does happen in an event that is dictated highly by small scale changes. Sometimes the initial trends are overdone and corrected, as we saw with the gfs. But we've also seen many times flip-flopping back and forth as the models hone in on a single outcome. I actually agree and doubt highly the end result is too dissimilar from the euro but it's not out of the realm of possibilities that things trend slightly better for us. It wouldn't take much for the ccb to trend further NW from its position on the 12z euro, which was just off shore. I just wouldn't bank on it. 

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As soon as I kept seeing the dual-QPF maxes and the main upper low start trending south I had a sinking feeling we could be in a sucker hole here and sure enough, it's still trending south and the heavy precip keeps getting shunted more and more. I'm still a little hopeful that this is overdone and we see some of it come back later tonight but the trends aren't encouraging, that's for sure.

 

 

Yeah, we would have been fine had the main upper low remained in its position. But it was certainly more of a delicate situation for us. This is one reason why I got so tired of the BL discussions...it was still so delicate as to whether we'd get heavy precip to begin with! 

 

It's still certainly close enough to where we could get back into it. And models have been making subtle adjustments during the short range. Tracking weather is too much fun for me to give up, but I'm certainly a bit deflated right now. 

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Definitely agree, but the euro has been very persistent with this feature for a couple of runs in a row now.

 

I agree that  feature is going to be a player in the forecast, but a small deviation in the trough axis

will result in some big changes over short distances. The models probably need until sometime

time tomorrow to refine the locations and amounts of snowfall with the Norlun-like feature. But 

New England usually does better than us in these events. Maybe we can get some more 

pivoting of the axis south in later runs to do better with the snowfall in parts of our area.

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You can see the feature on ewall.

A vort diving in from the lakes enhances the coastal low and temporarily stalls and throws back a wide area of precip.

 

Hour 48, vort diving in:

 

f48.gif

 

 

By hour 72, diving south of our area and enhancing the whole precip shield:

 

f72.gif

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Fwiw, that shortwave that yields the inverted trough feature on the Euro became much stronger and much further southeast on the 12z NAM compared to the 6z NAM. That shift wasn't enough to tug the surface low westward verbatim, but we can hope for more shifts like that with that feature and maybe we can even get the coastal precip to back in...not just an inverted trough.

 

Just food for thought as I try to remain optimistic. 

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Fwiw, that shortwave that yields the inverted trough feature on the Euro became much stronger and much further southeast on the 12z NAM compared to the 6z NAM. That shift wasn't enough to tug the surface low westward verbatim, but we can hope for more shifts like that with that feature and maybe we can even get the coastal precip to back in...not just an inverted trough.

 

Just food for thought as I try to remain optimistic. 

If it does, there will be some serious last minute changes. All hell would break loose on the board.

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Fwiw, that shortwave that yields the inverted trough feature on the Euro became much stronger and much further southeast on the 12z NAM compared to the 6z NAM. That shift wasn't enough to tug the surface low westward verbatim, but we can hope for more shifts like that with that feature and maybe we can even get the coastal precip to back in...not just an inverted trough.

 

Just food for thought as I try to remain optimistic. 

 

 

Agree Doug.

The GGEM also had this feature on it's latest run. But a bit later then the euro:

 

f60.gif

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You can see the feature on ewall.

A vort diving in from the lakes enhances the coastal low and temporarily stalls and throws back a wide area of precip.

 

Hour 48, vort diving in:

 

f48.gif

 

 

By hour 72, diving south of our area and enhancing the whole precip shield:

 

f72.gif

 

 

That shortwave is definitely more potent on the Euro than it was on the GFS. Hopefully the Euro is onto something with that. The best precip from that feature would also be at night. 

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i agree with much of what is being said by bluewave, dnsow et al...this s/w digging in behind could very easily trend stronger and faster, who knows. I think I prematurely threw in the towel earlier I think we need to see some consistency. Once that occurs its time to watch the radar and satellites.

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That shortwave is definitely more potent on the Euro than it was on the GFS. Hopefully the Euro is onto something with that. The best precip from that feature would also be at night. 

 

 

i agree with much of what is being said by bluewave, dnsow et al...this s/w digging in behind could very easily trend stronger and faster, who knows. I think I prematurely threw in the towel earlier I think we need to see some consistency. Once that occurs its time to watch the radar and satellites.

On the 12z NAM, however, that northern piece never phases in with the storm, which is why I think it has the best solution for our area. Initially, the shortwave diving in has a kicker effect of pushing away the CCB from us before the northern s/w finally captures it again and does a Fujiwara move to nail SNE. So I guess we better hope the NAM is right and the two shortwaves never phase fully, or we better hope the Euro is right and pulls this move off faster, lol 

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Agree Doug.

The GGEM also had this feature on it's latest run. But a bit later then the euro:

 

f60.gif

 

 

Interesting. Perhaps what's going on is that this feature initially acts as a kicker.

 

Since this feature is trending stronger and further southeast (but as of now, not enough to generate a phase early enough), it is actually acting as a kicker to the southeast before it phases in and provides the huge inverted trough feature. 

 

But, if this feature can continue to trend stronger and further southeast, it turns from being a kicker into being something that can hook some precipitation back earlier. There is only a certain extent to which this feature is a kicker...if we pass that threshold, perhaps we can save this storm. 

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On the 12z NAM, however, that northern piece never phases in with the storm, which is why I think it has the best solution for our area. Initially, the shortwave diving in has a kicker effect of pushing away the CCB from us before the northern s/w finally captures it again and does a Fujiwara move to nail SNE. So I guess we better hope the NAM is right and the two shortwaves never phase fully, or we better hope the Euro is right and pulls this move off faster, lol 

 

 

The 12z NAM actually keeps them separate through 72 hours. Perhaps this is why the NAM is further NW with its precipitation shield to begin with, as that feature does not have any kicker influence.

 

We can either go back to having those features be more separate, or go to having that feature diving in sooner. Right now, we're caught in between. 

 

Edit: Sorry, I misread your post...what you said is exactly how I feel. 

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Interesting. Perhaps what's going on is that this feature initially acts as a kicker.

 

Since this feature is trending stronger and further southeast (but as of now, not enough to generate a phase early enough), it is actually acting as a kicker to the southeast before it phases in and provides the huge inverted trough feature. 

 

But, if this feature can continue to trend stronger and further southeast, it turns from being a kicker into being something that can hook some precipitation back earlier. There is only a certain extent to which this feature is a kicker...if we pass that threshold, perhaps we can save this storm. 

 

 

The Euro and the NAM look very different at 72 hours, as the Euro has that feature fully phased in, and the NAM still has it remaining primarily separate and in SE Canada. 

 

nam_namer_072_500_vort_ht.gif

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i just looped the nam, the new gfs and the one from 18z last night. And in fact that s/w diving in initially does act like a kicker. The nam at 12z, doesn't have much doing with it, so it doesn't kick everything east much and the end result is similar to what had been showing up prior. The 12z gfs does have more of an interaction and it does kick everything east, albeit slightly. It is enough to take us out of any meaningful precip. Of note, last night the 18z gfs has very little interaction with this and it basically had no effect and it was kicked east at all leading to a further northwest and more amped solution.

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