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John1122

January 2019 Medium/Long Range Pattern Discussion

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The Euro looked pretty good. Especially for the western 2/3rd of the forum area. 5-6 days out the Euro/GFS are close. FV3 amped and cutter but still gets wintry in our forum area.  Canadian fairly weak. Still all models show some decent accums around our region. 

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Not much to add to the Jan 13 or so storm this morning. 6z Euro looks basically the same at H5 (only available out to 90 hours). Fv3 and GFS remained about the same as well at 6z. UKMET out to 144 shows a similar evolution to the Euro. Nice that neither Euro or UKMET have the Great Lakes low that the Fv3 and GFS show and both are south of the American models. Interesting that the MSLP locations on the GEFS are mostly south of the Ops track and along the Gulf coast. 

EPS 0z snowfall also improved for the Jan 13 -15 period. Only about 6 or so members blank the forum and the general 1-2" I mentioned a couple of days ago has upped to 2-4" across maybe 15-20 members. Still a few big dogs with 6" or more solutions. 

 

Long range continues to look good. EPS, GEPS, and GEFS in that order:

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It looks to me that the trend over the past few days has been an ever so slight delay, but pretty dang good agreement, once the flip happens. In my opinion the EPS looks the best of the bunch this AM.  

 

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9 hours ago, John1122 said:

GFS remained similar to its 18z with a little less backend action. Still a front end snow event with overrunning. Pretty common way to get snow here. Canadian is similar with the front end but weaker than the GFS. 

The 850s are really encouraging on the GFS. Will just have to see if they remain so. They blowtorched all but the very far eastern areas in early December and were borderline even on the best modeling.

Basically the far Southeastern areas are the only ones with 850 issues this time out.  So I think that even the middle Tennessee areas that it's showing a little more rain in would have a good shot at staying all snow, especially with any decent rates, with such a cold layer in place. 

I agree. 850's look good. While I've been burned putting too much emphasis on this feature in storms past, if they're cold enough and the warm layer is shallow enough, you can get away with a nice, wet snow. Either way, looks like I'll finally...FINALLY...be able to chase this weekend. Obviously, fingers crossed for nocturnal arrival, but the fact this system is moving in on a non-weekday smooths out the logistics for me.

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25 minutes ago, *Flash* said:

12z GFS is a screw job to middle TN. Thermals just don't seem like they'll cooperate this far out.

gfs_asnow_us_24.png

Take solace that Getting screwed means missing out on a statewide .5 inch or less

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All depends on where you live in the forum area in terms of what a "good run" is.  The 12z CMC(to some extent the 12z ICON though snow amounts are less) is a good run for MBY because it consolidates the energy and takes it to our SE and then north.  The 12z GFS is basically a Miller B which takes a slp into the TN and sends warm air into the almost all of the forum area.  As Bango noted, not a good solution for anyone.  Still a lot of variations for this are out there.  I like the hp that was shown over the GL yesterday...but it seems just a bit too far to the north which might allow the system to drive west of the Apps.  I think the Miller B scenario is very plausible with the way the confluence sets up.  I would also not rule out a Miller A.  Either is possible, especially with several more runs before possibilities narrow.   I lean mostly rain on this one, but could easily be wrong, especially along the northern border of TN.  Sometimes NE TN can steal some snow if the Miller B transfers far enough to the southeast.  Models are all over the place right now which is indicative of the pattern getting ready to change IMHO.  If you live in E TN, you want the energy consolidated, passing to our south, and then NE.  If you live in middle or west TN, you want the slp to drive close to the spine of the Apps or just on either side depending on your location.  At this point, my confidence in it snowing more than inch IMBY would be considered moderately low.

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I would recommend taking a look at the ensembles.  At this range, I would give the operational about the same weight as one of the individual ensemble members....though is trends would matter.

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UKMET looks Miller A/ B hybrid-ish to me:

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Still not as north as the GFS, but UK took a step in that direction IMO. 

As Carver's said, several tracks on the table. In one way I'm glad I'm not in the bulls eye at 5 days and the major player key for all this an upper low that gets totally shredded on both American and Euro guidance as it hits the W Coast and then has to somehow reconsolidate to the lee of the Rockies:

giphy.gif 

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Still a ways to go

 

 

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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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Even the CMC is too warm. *Sigh* Right now, 57/64 locales lookin' good. That 1044 HP, while too far north ATM, doesn't seem to get too far ahead of the L unlike the 12/9 system. If that dive south @126-150 can be more S than E, who knows if that will help much. Whatever the case, your primary players need a 100-150 mile nudge south for this to be thread-worthy (at least for western 2/3rd's of TN). I'm sure the bullseye will change throughout the week, but overall this storm is a step in the right direction. Last week at this time, things were lookin' much more dire. 

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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: 

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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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44 minutes ago, Carvers Gap said:

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.

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.

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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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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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