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John1122

January 2019 Medium/Long Range Pattern Discussion

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The 12z FV3 is a text book Miller B.  Maybe a quick front end thump in NE TN and CAD in western NC.  The primary goes to Nashville w the secondary forming near Wilmington.  Pretty much a warm look if the pressure maps are correct.  The parent hp is just too far to the north in Canada - nothing to hold that slp to the south.

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The snow map for the FV3 likely has a lot of ice.  Looks like the 1040+ hp over southern Canada is slow to move.  It continues to pump cold air down the west side of the Apps.  It does not slide off.  If this comes in at night or early morning with temps just above freezing(just speaking of this run...not a forecast), that could trap the cold in the Eastern Valley.  If the slp jumps to the coast...very little downslope to move it.  Interesting run, and a bit more potent than the mslp anomaly that ran first.  

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Taking my first look at this weekend, after focusing mainly on sports. I am not at all inspired to be quite frank. Looks like light snow is a good bet for the Plateau, Mountains, and perhaps TRI. Also West Kentucky could get thumped. However most of the lower elevations of our our sub-forum (Tennessee) look like cold rain to me.

ECMWF is a little colder (thickness/850) but weaker with the upper level system. Low levels will be too warm. GFS* has a stronger upper level system, but last two runs trending toward warm tongue. Thickness and 850 both retreat ahead of low press. Seems like both models have issues not pulling everything together correctly. Anybody surprised? The South. 

*GFS Para / FV3. I do not even look at the old GFS much, I know it had a good run, but it's such a bad model.

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12z Euro is further north than 0z (not quite as far north as the GFS), but has a new fly in the ointment. The odd ball temporary PNA ridge that will help propel the energy is now being attacked to the north by a shortwave over Alberta. Furthermore the shortwave crashing into CA is trying to interact not just to pump up the ridge, but also sneaking closer underneath that ridge towards the energy that will give us the storm.  Almost looks like the Euro is trying to do two distinct waves. One front end wave and then a more consolidated upper low. 

Cutoff ridge out west is really unique. If cutoff cyclones are hard to forecast, I bet cut off anticyclones are too? Not saying it will help much. We just need some nice cold air, no more marginal mess, but still will be interesting evolution over the next few days. 

The CA energy actually seems to function to stretch out the energy with the second wave of our storm and weaken it on this run.

 

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31 minutes ago, Holston_River_Rambler said:

Stepping back from the storm for a minute and looking at the overall pattern, a big shift for the Euro at overall N. Hemisphere pattern (at a week + out so maybe not that unusual) last 24 hours: 

giphy.gif 

The Euro operational throwing out its first look at a potential reversal.  It will likely be different on future runs, but it is important to begin to see operationals begin to show that look(even if it is not every run).  FTR, I am not overly impressed with the EPS.  During this winter it has missed some key amplifications during its d10-15 time frame which is fairly understandable given its range...but still, it has missed them IMO.  I am using the control during d10-15 more than the mean.  That is why it is nice to at least a glimpse on the Euro operational.

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EPS mean still somewhat suppressed/ washed out with the 13-15th storm and seems to favor later development off the coast. Individual members (going only by snowfall) in days 0-5 do seem to favor SE Missouri and N. Arkansas, but a fair number push that snow east and not northeast. In days 6-10 a few solutions show the late development of the second wave with a little more snow east. Still only talking on average 1-4". 

 

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9 minutes ago, Holston_River_Rambler said:

EPS mean still somewhat suppressed/ washed out with the 13-15th storm and seems to favor later development off the coast. Individual members (going only by snowfall) in days 0-5 do seem to favor SE Missouri and N. Arkansas, but a fair number push that snow east and not northeast. In days 6-10 a few solutions show the late development of the second wave with a little more snow east. Still only talking on average 1-4". 

 

ONLY 1-4”???  You must have forgot what forum we are in.  Haha. That’s my yearly average nearly!!! :)

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Just now, Holston_River_Rambler said:

Hey no, I'd be happy with 2", just didn't want anyone to get the wrong idea!

I know it buddy, I’m just messing with you.   I’d be happy with 2 as well.

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57 minutes ago, *Flash* said:

That -NAO/-AO signal is a nice look, albeit an interesting one given BN heights up in Baffin Bay don't often correlate well for us. Still, gotta love that EPO trough weakening as the east coast trough both strengthens and retrogrades the ridge into the midwest. Of course, the southwest s/w bias should surprise no one, but overall...I'll cheers to this.

Yeah, that is a headache.  But pretty sure those don't teleconnect well to rising heights in AK and the Davis Straits.  JB mentioned those this AM on his discussion. He thinks the cold under those heights heads south...I have no idea if that happens or not.  

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@*Flash*, I also think those BN heights are a by-product of the strat split - I could be wrong.  Not all strat splits are the same, and not all of them are good.  However, the blocking is also a result, and that is good.  I have often thought we would have been just fine this winter without the SSW.  The mechanisms that induced the strat split(I am thinking abnormal El Nino MJO) have likely caused 4-5 weeks of winter to be warm and rainy.  Without that amped MJO and the subsequent strat split(earlier than I had imagined), I think we would have maintained a cold base state.  As it is, we have had to deal with yet another winter that has some La Nina characteristics.  Not saying this is a La Nina(definitely Nino), but the +SOI and MJO combo have been the recent dominant driver unexpectedly.  I feel nearly certain that this year will have not match as an analog.  It will be a truly unique entity that will stand alone.  I noticed those BN heights over Canada a few days ago.  I thought they might just be the wx models working out the new pattern.   I first noticed them retrograding from the Davis Straits.  The problem with them is that they cut cold off from coming over the pole and being wrapped up tightly, don't allow the cold to come south.  JB is complaining about them this afternoon.  I do agree with this premise...once they are gone, the door is open for very cold air to rush south.  That is a near perfect high latitude blocking pattern.  Now, the real pain in the neck is if the MJO cycles into warm phases just as that area goes AN heights and we lose the mechanism to deliver the cold.  It is unfortunate that it is there right now.   I think very cold air is on the table should that blocking hold.  And SSW blocking has a tendency to stay in place for a couple of months...In the end, I think Nino climatology enhanced by high latitude blocking wins.

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17 minutes ago, Carvers Gap said:

@*Flash*, I also think those BN heights are a by-product of the strat split - I could be wrong.  Not all strat splits are the same, and not all of them are good.  However, the blocking is also a result, and that is good.  I have often thought we would have been just fine this winter without the SSW.  The mechanisms that induced the strat split(I am thinking abnormal El Nino MJO) have likely caused 4-5 weeks of winter to be warm and rainy.  Without that amped MJO and the subsequent strat split(earlier than I had imagined), I think we would have maintained a cold base state.  As it is, we have had to deal with yet another winter that has some La Nina characteristics.  Not saying this is a La Nina(definitely Nino), but the +SOI and MJO combo have been the recent dominant driver unexpectedly.  I feel nearly certain that this year will have not match as an analog.  It will be a truly unique entity that will stand alone.  I noticed those BN heights over Canada a few days ago.  I thought they might just be the wx models working out the new pattern.   I first noticed them retrograding from the Davis Straits.  The problem with them is that they cut cold off from coming over the pole and being wrapped up tightly, don't allow the cold to come south.  JB is complaining about them this afternoon.  I do agree with this premise...once they are gone, the door is open for very cold air to rush south.  That is a near perfect high latitude blocking pattern.  Now, the real pain in the neck is if the MJO cycles into warm phases just as that area goes AN heights and we lose the mechanism to deliver the cold.  It is unfortunate that it is there right now.   I think very cold air is on the table should that blocking hold.  And SSW blocking has a tendency to stay in place for a couple of months...In the end, I think Nino climatology enhanced by high latitude blocking wins.

It will be interesting to see if the MJO can have an impact if it cycles through to a low amplitude warm phase.  Maybe something else drives the bus for a while?

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26 minutes ago, tnweathernut said:

It will be interesting to see if the MJO can have an impact if it cycles through to a low amplitude warm phase.  Maybe something else drives the bus for a while?

Man, I hope so.  I am ready for the El Nino to take over.  

Edit:  With precip it has taken over...need it to induce blocking.

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18z shifted south by around 100 miles and brought the heavier snow back into the forum area. Heaviest axis shifted from the Ohio River to Southern/Central Kentucky/SW Virignia. Northern Arkansas and the Western Carolinas also take a big shot. 

It was mainly due to a slightly stronger high that was slightly further south. The high almost assuredly won't be as strong as modeled. But if it is, more of us will be in the game. 1040+ highs mean business.

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3 minutes ago, John1122 said:

18z shifted south by around 100 miles and brought the heavier snow back into the forum area. Heaviest axis shifted from the Ohio River to Southern/Central Kentucky/SW Virignia. Northern Arkansas and the Western Carolinas also take a big shot. 

It was mainly due to a slightly stronger high that was slightly further south. The high almost assuredly won't be as strong as modeled. But if it is, more of us will be in the game. 1040+ highs mean business.

Noticed that about the high as well...and if it stays west of the Apps for most of the event, that is a positive in our favor.  Many times those things just slide off.  It has stayed west of the Apps on the American suite.  Might be that ice is a problem if this comes in at night.  

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Weeklies. I think I flipped maybe weeks 4 and 5, but the look really doesn't change that much. 

giphy.gif 

I was expecting a good EPS/ control version of a NAMing with that look, but twas not to be. Maybe that's a good thing though, since the control/ EPS mean has had these sick looks in the 15+ day range and never really delivered. 

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FV3 is stuck at 90 for me, but at that hour it's about 200 miles SSW with the LP placement over west Texas vs 12z. HP look similar pressing down into Minnesota. Will have to see if it stays more over the top or if it moves ahead and lets it cut.

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1 minute ago, John1122 said:

FV3 is stuck at 90 for me

Found this cruising around the MA forum today. Goes faster than TT: https://mageval.ncep.noaa.gov/model-guidance-model-parameter.php?group=Model Guidance&model=gfs&area=namer&cycle=20181205 12 UTC&param=snodpth_chng&fourpan=no&imageSize=M&ps=area&fhr_mode=image&loop_start=-1&loop_end=-1 

Its says GFS, but it is the Fv3. Not as nice as TT, but gets the job done. 

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The Weeklies held serve as Holston posted.  Cold has moved up in time.  Here is week 3.  (d11-18 is the switch to cold temps with the 500 pattern beginning during d7-14). Really, it is as good a look as one could ask for.  Blocking until week 7 when it finally relaxes.  If it verifies, we will be glad it finally turns warm.  Here is the d14-21 850 hindcast map.  Be warned, sometimes the "normal" weeklies are not the same.

edit: 2m temps don't look as impressive but still cold.  The week of Jan 21-28 is cold on this run...still rolling, but should last for most of the run.  This is what drops in when that last ridge(after the weekend storm) finally rolls through.

Screen Shot 2019-01-07 at 6.36.44 PM.png

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7 minutes ago, John1122 said:

I'd take this look all day. No way that LP is that far north imo with a 1045 high right over the top of it.

fv3p_mslp_pcpn_frzn_us_21.png

John, if that 1040+ gets established...that potentially has some ice if not snow, right?

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Take d16 w a grain of salt...just wanting to see if the Weeklies have any support.  You decide.  d16 of the 18z GEFS.  Pretty far out there so view at your own risk...

467533236_ScreenShot2019-01-07at6_58_46PM.png.56f4190b2877dcfbdbe221d2fce8f2a3.png

 

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Watching the 18z Euro roll in and it looks better to me for the 13-15th event. Ridge higher and steeper and energy slower, deeper, and more south heading into So. Cal.

So complicated though. 

Not (1), not (2), but (3) shortwaves trying to interact on the east side of a ridge cutting off as a bigger, more consolidated shortwave (7; sorry not sure how I numbered it 7) pumps up that ridge while at the same time trying to creep beneath it and join the energy over AZ.  Huge vortex over Maritime Canada trying to suppress. A tiny but important shortwave (black arrow) that, even though it looks like it is part of the others, is actually it's own little vort. near Lake Superior. Tropical connection (4) too (surprise this year, I know). 

euro 18z.png

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