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2013-14 MA Winter Disco - 'cause it's never too early.


Bob Chill

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I guess the semi good new is that the ens forecasts of the AO are for it to drop quite a bit with most members taking it negative in the 14 day range.  The pattern on the superens mean looks less good, A nice negative EPO look but lots of negative heights over Canada. looks good maybe for the northern tier but not so good south of 40 (at least to me).  

 

45, 67, 63, 42, 44, 59, 63, 58...Washrinserepeat

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I chatted with him last night, and he is super focused on QBO progression....so I don't know...this is a tough winter...I have never been too focused on QBO beyond a quick look though maybe I should...I do pay some attention to it...in 2009 i said the -QBO/Solar min combo would lead to sig blocking...because there is a def correlation there...but it has become a cornerstone for DT....he also thinks we may get this late developing Nino based on the sub surface....

 

"SUMMARY not a mild winter. 

DEC colder than Nornal SOME snow chances 

JAN Normal maybe eveb slightly above Normal

FEB colderthan Normla good snow chances which will last into March and delayed spring

IF weal el ninoe develops late FEB & MARCH 2014 could be historic

analog winters 1957-58 1959-60 1969-70 1995-96 200-03 2006-07.. Most of those selected winters were BIG bad winters but SOME of those were el nino winters. WE begin the winter NEUTRAL but may move into Weak El Nino late..."

this isn't real scientific, but I've noticed that when the QBO is going from + to - as it is doing now, if the number stalls on the way down or it starts back up a 2nd time before dropping again to -, we have a lousy winter snow-wise

http://www.esrl.noaa.gov/psd/data/correlation/qbo.data

see winters of 80/81, 85/86, 90/91, 06/07, 08/09 and to a lesser extent 10/11

we seem to do better in winters that follow steady up and then down (97/98 an exception thanks to super NINO)

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This is where I need some tutoring. It doesn't have to be a southern stream from the pacific into Texas does it? Just a flow that doesn't cut off the gulf? Can't a disturbance in the flow cause low pressure development in the gulf or se? Just need a trough deep enough and west enough to allow it to happen? Help.

 

I dug this up from my screen snip archive:
 
 
 
Obviously a very extreme example (2/3/10) but it's a pretty stark representation of how an active stj fuels big storms as they track the sw. The moisture goes all the way back to HI (pineapple express). We simply don't get this kind of setup in non-nino years. We end up needing split flow for big storms more often than not. 
 
Split flow isn't nearly as robust as a strong stj. All split flow means is there is ridge off the coast of CA (I think usually REX style) that allows upper level flow underneath the ridge that helps add some pac juice to storms when a disturbance in the polar jet is diving down out of canada. The southern stream of split flow isn't robust or moisture laden like a an active stj. 
 
I don't have the corresponding h5 map for this panel but this is 200mb winds. Shows an example of split flow:
 
 
 
ETA: one of the most frustrating parts of split flow is timing. There is energy cruising along with both streams. More often than not, to get a solid miller A we need to time/phase both streams. Models love teasing us days in advance. Some runs are perfect harmony while others are agonizingly painful. Many a rug can be pulled out but it can happen. Sometimes we can get lucky with a robust vort embedded in the southern stream and not needing to phase the northern stream. I can't remember specific examples of either to be honest. I'm sure Matt has more details. 
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I dug this up from my screen snip archive:
 
 
 
Obviously a very extreme example (2/3/10) but it's a pretty stark representation of how an active stj fuels big storms as they track the sw. The moisture goes all the way back to HI (pineapple express). We simply don't get this kind of setup in non-nino years. We end up needing split flow for big storms more often than not. 
 
Split flow isn't nearly as robust as a strong stj. All split flow means is there is ridge off the coast of CA (I think usually REX style) that allows upper level flow underneath the ridge that helps add some pac juice to storms when a disturbance in the polar jet is diving down out of canada. The southern stream of split flow isn't robust or moisture laden like a an active stj. 
 
I don't have the corresponding h5 map for this panel but this is 200mb winds. Shows an example of split flow:
 
 
 
ETA: one of the most frustrating parts of split flow is timing. There is energy cruising along with both streams. More often than not, to get a solid miller A we need to time/phase both streams. Models love teasing us days in advance. Some runs are perfect harmony while others are agonizingly painful. Many a rug can be pulled out but it can happen. Sometimes we can get lucky with a robust vort embedded in the southern stream and not needing to phase the northern stream. I can't remember specific examples of either to be honest. I'm sure Matt has more details. 

 

 

 

I think there are a number of configurations to split the streams, but it is usually a rex block as you mentioned with the closed low or trough to the south of the block or to the west of the block (like Feb 2010)....I think you actually want the low off the NW/California coast with the high to the  north like the vertical configuration like below...jan 2000 was a good example of that...without it as Will mentioned we have no phase and no storm,...

 

post-9749-0-04244800-1384534046_thumb.jp

 

post-9749-0-64781900-1384534056_thumb.gi

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I think there are a number of configurations to split the streams, but it is usually a rex block as you mentioned with the closed low or trough to the south of the block or to the west of the block (like Feb 2010)....I think you actually want the low off the NW/California coast with the high to the  north like the vertical configuration like below...jan 2000 was a good example of that...without it as Will mentioned we have no phase and no storm,...

 

attachicon.gifimages.jpg

 

attachicon.gifcompday.XHH2T98wlO.gif

funny you should be talking about that storm

I found some home video from that day last night that I forgot I had

I had completely forgotten that the snow and wind that day, at least at times, was comparable to 2/10/10

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funny you should be talking about that storm

I found some home video from that day last night that I forgot I had

I had completely forgotten that the snow and wind that day, at least at times, was comparable to 2/10/10

 

to me the winds before the storm tell the story....Around dinner time on the 24th, winds picked up and it was as ominous a feeling as I have ever felt before a storm...very gusty winds

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I dug this up from my screen snip archive:
 
 
 
Obviously a very extreme example (2/3/10) but it's a pretty stark representation of how an active stj fuels big storms as they track the sw. The moisture goes all the way back to HI (pineapple express). We simply don't get this kind of setup in non-nino years. We end up needing split flow for big storms more often than not. 
 
Split flow isn't nearly as robust as a strong stj. All split flow means is there is ridge off the coast of CA (I think usually REX style) that allows upper level flow underneath the ridge that helps add some pac juice to storms when a disturbance in the polar jet is diving down out of canada. The southern stream of split flow isn't robust or moisture laden like a an active stj. 
 
I don't have the corresponding h5 map for this panel but this is 200mb winds. Shows an example of split flow:
 
 

 

 

How far into the weeds do we get if I ask "Why not?"

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How far into the weeds do we get if I ask "Why not?"

 

 

we've actually gotten a split flow pattern at times the last couple winters...even 2011-12...but there was nothing going on in the southern stream so it didn't matter...you still need a storm

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How far into the weeds do we get if I ask "Why not?"

 

This is a good simplification:

 

 

 

El Nino's aren't good for everyone. Just us and the SE. Nino's almost always bring an active storm track into socal and 4 corners. Doesn't always mean we get snow either because we need some additional help. Nino's are generally warm for the entire conus as a whole. But they are good precip makers for the entire southern half of the country. 

 

Our latitude is tricky. The "middle" in the MA is a bit of a disadvantage. Nino's bring the highest odds of good precip. But we are constantly in between airmasses. Without a nino we're too far south more often than not for both precip and snow more often than not. 

 

As matt said, we can get split flow various ways in any year. But having a split flow + a storm is another beast all together. Nino's sharply increase those odds. 

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Thanks for the answers, both of you.

 

I realize that a Nino leads to an active STJ, but I guess one of things I'm most curious about is the physics of why that's the case.  It's only a few degrees difference in water surface temps, so how is it that those few degrees have such a drastic effect on the weather over a hole continent (if not more)?

 

And by "getting into the weeds," I was afraid of asking just in case the physics of it is too heavy.  I'm not a science guy, so it all might be over my head.

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Thanks for the answers, both of you.

 

I realize that a Nino leads to an active STJ, but I guess one of things I'm most curious about is the physics of why that's the case.  It's only a few degrees difference in water surface temps, so how is it that those few degrees have such a drastic effect on the weather over a hole continent (if not more)?

 

And by "getting into the weeds," I was afraid of asking just in case the physics of it is too heavy.  I'm not a science guy, so it all might be over my head.

 

It isn't just a few degrees...ithe difference between a strong nino and strong nina is like 7-8 degrees fahrenheit

 

HM and others can get more into this...but it isn't just about temps...it is the other phenomenon that are part of el nino...prevaling winds, air pressure, forcing...temps are just the verification method...the mechanics of the oscllation are much more complex..

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The biggest impact of El Nino (that we care about in winter for us) is the warmer water in the central/eastern Pacific allows convection to move to the central Pacific...the stability is broken down with the warmer water. The increased convection then affects the larger scale hadley cell circulation...which in layman's terms is what helps cause the typical low anomaly in the north pacific south of the aleutians and the high pressure pressed north of the equatorial regions...the gradient between the two enhances the STJ.

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As HM has suggested, the Euro is now showing a  Nino like pattern to end the month and some of the analogs I am getting for the last week of November and 1st half of december are promising

Euro suggests your forecast contest is a tricky one.  Wavers the very cold/seasonable air boundary back and forth over us late next week/weekend. 

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Euro definitely solid below norm from our latitude south but I think much of it is in response to the big low down in tx/ok and compressed flow to our north. It's kinda on it's own there. I know snow weenies in texarkana are praying the euro is right. Wow. Snow into LA, AL, MS, and even GA. But then I look at the calendar...

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Euro definitely solid below norm from our latitude south but I think much of it is in response to the big low down in tx/ok and compressed flow to our north. It's kinda on it's own there. I know snow weenies in texarkana are praying the euro is right. Wow. Snow into LA, AL, MS, and even GA. But then I look at the calendar...

 

I am going 12-18 for the DC metro area....

 

 

 

 

just down know 12-18 of what yet

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The biggest impact of El Nino (that we care about in winter for us) is the warmer water in the central/eastern Pacific allows convection to move to the central Pacific...the stability is broken down with the warmer water. The increased convection then affects the larger scale hadley cell circulation...which in layman's terms is what helps cause the typical low anomaly in the north pacific south of the aleutians and the high pressure pressed north of the equatorial regions...the gradient between the two enhances the STJ.

Thanks, ORH. That was exactly what I was wondering about, and it was dumbed down enough for someone like me to grasp.

Thanks to zwyts and Bob, too.

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This is a good simplification:

 

attachicon.gifnino-nina.JPG

 

 

El Nino's aren't good for everyone. Just us and the SE. Nino's almost always bring an active storm track into socal and 4 corners. Doesn't always mean we get snow either because we need some additional help. Nino's are generally warm for the entire conus as a whole. But they are good precip makers for the entire southern half of the country. 

 

 

 

Bob,

 Regarding what I highlighted, that's definitely not the case for weak Ninos, which often lead to cold in much of the E 1/3 to 1/2 of the US. For strong Ninos outside of the SE, I'd agree for sure. But a good number of the coldest winters in the E US have been weak Ninos: 1976-7, 1977-8, 1969-70, 1939-40 1904-5 among others.

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