December/January 2019/20 Winter Speculation Thread

[Carvers Gap]

The weather pattern that many are focusing on is about ten days out, maybe nine now.  The Euro OP was likely heading to an eastern trough late in its run.  The 6z GEFS is definitely there.  I wasn't a huge fan of the EPS overnight as I thought it took a step back.  The Weeklies two runs ago(on Monday) pushed a temporary trough eastward in early January, and then pulled it back West for most of January. OTH the Weeklies on Thursday, pulled it back and then eventually would send multiple shots of progressively seasonal to cold air eastward - looked like November.  The 12z EPS yesterday looked firmly in the camp of Thursday's run.  The 0z overnight still looked like Thursday's run, but slower...almost to the point it looks similar to Monday's bearish run.  The models showing something good and then pulling it back has been happening for about a month.  If one just splits the difference, like means we are dealing with some above normal heights over the coastal SE for a time(likely won't stay there as El Nino climatology really won't want it there).  

Bottom line:  Proceed with caution, but also know we are approaching the time when modeling potentially could begin showing signs of a flip.  We have been AN since roughly the beginning of the second week of December.  Patterns usually(barring last winter's catastrophe...LOL) run about 4-6 weeks.  So, I could see a couple of realistic scenarios.  The warm pattern (that we have been in for a couple of weeks already) ends prematurely around January 1 OR the pattern relaxes around January 1 only to flip a couple of weeks later in mid-January.  December 7 to Jan 15 is about 39 day(almost six weeks).  It is very possible the models are jumping the gun, will pull back, and eventually buy in.  Remember how the warm-up was modeled?  Sort of went like this during several model suites in succession: warm, cold, warm, warm, cold, warm, warm, warm....and the warm pattern kept getting pushed back and eventually arrived during the second week of December.  I would not be surprised if we see that same progression as we turn much colder.  The real fly in the ointment is if the TPV just sits up around the North Pole and tightens up.  They are due a cold winter at that very high latitude.  So there is that.  Will be interesting to follow the MJO saga this morning.     

Back to loading...keep the fires burning!

[Carvers Gap]

Indeed, the MJO this morning progresses into 7 and loops back into 6 which explains some of what we are seeing on modeling this morning in terms of a step back.  My guess is that (if it does that), it will eventually loop back or not happen at all.  But one can see why modeling is flip-flopping.  Yesterday's MJO was nearly textbook for cold...overnight, not so much.

[tnweathernut]

Morning SOI update.

The SOI is at -14.38.  10 straight days of negative departures.

[Carvers Gap]

That is a BIG drop of the SOI.

And the 12z EPS. That is an incredibly cold look during the d10-15.

[jaxjagman]

18 hours ago, Mr. Kevin said:

Hi jax. Can you tell me how to read the qbo chart from singapore again? Its confusing me because it dont show no forecast for the qbo moving forward. Not sure where it is now as in has it reversed fully at 30mb or 50mb easterly? Cant tell by the previous maps. Also, does anyone know where to pull up AAM charts? Imo, if it can go positive, we should be ok.

The charts update monthly.The daily QBO map still shows shows westerlies, i put a point on it on the 50hpa,so basically you want to see on the graph bar the line on  the chart on the other side.You can also use Berlin zonal winds for a prediction,it shows the westerlies decreasing in the upcoming days,if it's right of course,they both show something different today

[jaxjagman]

Be interesting to see how the RMMS do,you have alot of stuff that's fixing to happen along the IDL,a low, Rossby wave , Kelvin Wave ,WWB with a more suppressed IOD for a change,the strongest SST'S along the IDL.I still wonder if they will whiff out,but that's what they show right now

[Carvers Gap]

Talk about some cold ensemble runs today.  Wow.  That EPO ridge in conjunction with a mid-Atlantic ridge will create a block that could potentially discharge very cold air into much of the United States and Canada.  I definitely want to see some run-to-run continuity before really jumping on the cold train.  The MJO gives me some pause.  But make not mistake, if those ensembles(EPS and GEFS at 12z) verify, that would create a highway for cold air to reach clear to the GOM.

[weathertree4u]

33 minutes ago, Carvers Gap said:

Talk about some cold ensemble runs today.  Wow.  That EPO ridge in conjunction with a mid-Atlantic ridge will create a block that could potentially discharge very cold air into much of the United States and Canada.  I definitely want to see some run-to-run continuity before really jumping on the cold train.  The MJO gives me some pause.  But make not mistake, if those ensembles(EPS and GEFS at 12z) verify, that would create a highway for cold air to reach clear to the GOM.

What kind of cold are we talking? Vodka cold or just cold cold? If it is Vodka cold, systems will be shunted south of the TN Valley and places like Montgomery AL will be getting our snow lol

 

[jaxjagman]

44 minutes ago, Carvers Gap said:

Talk about some cold ensemble runs today.  Wow.  That EPO ridge in conjunction with a mid-Atlantic ridge will create a block that could potentially discharge very cold air into much of the United States and Canada.  I definitely want to see some run-to-run continuity before really jumping on the cold train.  The MJO gives me some pause.  But make not mistake, if those ensembles(EPS and GEFS at 12z) verify, that would create a highway for cold air to reach clear to the GOM.

Sure looks like we are seeing  pattern change into Russia into Mongolia

[Mr. Kevin]

5 hours ago, jaxjagman said:

The charts update monthly.The daily QBO map still shows shows westerlies, i put a point on it on the 50hpa,so basically you want to see on the graph bar the line on  the chart on the other side.You can also use Berlin zonal winds for a prediction,it shows the westerlies decreasing in the upcoming days,if it's right of course,they both show something different today

If I'm reading the map correctly, today at least the 50mb level is only westerly compared to everything else?

[Mr. Kevin]

Seriously, why is it important to see the SOI remain negative or continue to drop negative?

[jaxjagman]

8 minutes ago, Mr. Kevin said:

Seriously, why is it important to see the SOI remain negative or continue to drop negative?

It shows a more Nino pattern and a potential more Modokish look

[Mr. Kevin]

2 minutes ago, jaxjagman said:

It shows a more Nino pattern and a potential more Modokish look

Thank you jax. If we could get the -epo, then i may would consider backflips and cartwheels, but not until then. 

[TellicoWx]

Thank you jax. If we could get the -epo, then i may would consider backflips and cartwheels, but not until then. 

Remember it's not only the -epo number, but more importantly, the orientation. You want to see the epo and/or PNA ridging be meridonial (N/S oriented) vs tilted more E/W. Too much tilt and the cold would spill west of the Rockies and promote a SER here for us.

Sent from my SM-S767VL using Tapatalk

[jaxjagman]

7 minutes ago, TellicoWx said:

Remember it's not only the -epo number, but more importantly, the orientation. You want to see the epo and/or PNA ridging be meridonial (N/S oriented) vs tilted more E/W. Too much tilt and the cold would spill west of the Rockies and promote a SER here for us.

Sent from my SM-S767VL using Tapatalk
 

Yeah but seemingly we are fixing to lose wave-2 and wave-1 will seemingly start to weaken as the heights get pumped into Siberia some what to speak.This should strengten the PV later on but the blocking would push the PV towards NA,I have my doubts we will see a SSW.JMHO

[John1122]

The GEFS was bone chilling and the cold is getting into the day 10 window instead of hanging out at 14-16. 

[jaxjagman]

59 minutes ago, John1122 said:

The GEFS was bone chilling and the cold is getting into the day 10 window instead of hanging out at 14-16. 

Like the last weeklies of the EPS,into wk 2-3 -EPO,then it goes into a more -NAO afterwards,we should have snow chances here in Mid and western Valley from cutters,after this if its right,it will be a sob story for us in the Mid and western Valley other than snot blowing cold noses wk 4,it will turn colder seemingly

[jaxjagman]

I would not be shocked if this Jan is not right,the EPS shows it from an EPO.But into winter when the NAO goes negative,we will be doomed in the Mid and western Valley.I'll be in Chicago the middle Jan for my sons gymnastics meet.We got lucky last year and it snowed about 6 inches while we was there,the year before that we walked around the zoo there in short sleaves..doh !!

[Carvers Gap]

Looking for some run-to-run continuity....not there yet.  Yesterday's 12z model suite was about as cold as I have seen it from a 500 persepective.  And yet again, the overnight EPS went warmer - would still be decent cold for winter but not the extreme 500 look.  I have a realistic theory as to why this happens - no conspiracy stuff. Think about when the sun hits the areas of the MJO and fires the convection there and think about when Siberia is coldest.   I suspect(though far from certain) that data gets dumped into modeling overnight.  Then, as the MJO region and Indian Ocean regions cool due to overnight temps...the MJO looks slightly different at 12z due to less intense convection.  Also, those frigid overnight low temps from Siberia begin to get inputed.  It is uncanny to see the overnight suite continually reverse course from the 12z suite or mute trends.  So, in theory, makes me wonder if daytime convection on the other side of the planet is fouling the MJO and thus inputing a different MJO than its opposite run.  When I say the MJO is bouncing around, it is bouncing wildly.  I do lean cold for the second week of January...but as I noted yesterday, the past two runs of the Euro Weeklies are very realistic and very different for our region.  The current pattern could go either direction:  1.  Trough lifts out of the West and gives us a brief but intense cool down and then re-establishes out West 2. The trough could roll eastward and lock into the East.   When one looks at the EPS, it really looks like it is stuck in between those two solutions.  You can kind of see how the full latitude trough is colder on one side of NA than the other at the same time frame and then flip-flops.  Looks to me like it hasn't quite worked that out yet.  I think the full latitude trough solution is actually in error(might be correct for a few days).  I think the full latitude trough solution is the EPS actually having two different tough placements on the same ensemble map.   So, I definitely advise caution in the LR.  While yesterday was awesome and I admit that I was excited...the morning's 6z GEFS and 0z EPS return us to their usual uncertainty.

[John1122]

The 12z Euro looks better at day 10 than the 00z did. 00z had the PV deep into Alaska which turned the flow into the lower 48 off the Pacific. Well north of Alaska on the 12z. 

Looks way more workable here. Blocking in Eastern Canada, blocking on the West Coast. Flow coming more off Russia and across the pole straight into the lower 48.

[jaxjagman]

You can see at least right now how into Russia the pattern we are in is getting broke down,at least right now

[Carvers Gap]

I have sounded like a broken record for nearly three weeks.  The LR trends are for a western trough with a brief relaxation around the New Year.  The stage is set for a very warm overnight run of the EPS.  Its LR usually takes about two runs to really flip.  A cold Alaska is a teleconnection for a very strong SE ridge.  The MJO is now forecast to loop back into phase 6 on the American suite which is usually cold - not good.  The MJO on the European sweet is COD or low amplitude warm phases.  Right now, I have low confidence that yesterday's 12z cold ensembles are correct.  Looks more and more like a brief relaxation and then a return to a warm or even very warm pattern.   It is possible and even likely that wx models jumped the gun(or the shark) yesterday.   Again, this current pattern began around December 8th.  Have to add nearly 35-42 days to that date before we see the pattern break down.  I think what we are likely seeing on modeling are some early signals that the pattern is about to break down, but not there yet - or anywhere close as a +AO, +NAO, and +PNA are showing up in modeling.  Tough to get any sustained cold from that.  Yesterday, it appears was indeed a wicked head fake.  We need the EPS to break back as it is absolutely schooling the GEFS and GEPS right now in the LR.  It wasn't a few weeks ago, but the GEFS is now playing catch-up and is about 24-36 hours behind the EPS.

[tnweathernut]

Euro LR seems to revert to something less than desirable, but the day 10-12 look is pretty good.  It shows how something can be squeezed in this time of year when a front-running system cuts into the northern plains/great lakes and another piece following should be forced further south.  Trusting modeling beyond day 4 is not a good idea, but at least it's active.

[jaxjagman]

The MJO should be fun to follow.I don't mean to keep harping it.The WWB upcoming looks really strong west of the IDLwith a passing KW and ERW which more than likely will spawn a TC .The CFS today totally flipped the evolution of the signal.This ERW is what the RMMS show going back into the Maritime,remember,Rossby waves moves east to west,lots of destructive signals

[John1122]

12z EPS at day 10 looks even better than the OP. Polar vortex into north central Canada rather than Alaska.  We don't want the pv to get into Alaska at all. 

[John1122]

Larry Cosgove today said he liked snow chances from the Rockies to the Apps through the first 3 weeks of January.  Said southern tracks that cut the Carolinas would be possible, didn't like I-95 corridor in a broad Rockies to Apps trough set up. Mentioned there's not going to be blistering cold, but cold enough air to work for a lot of areas west of the Apps. 

Sounds like a good set up for us, especially the mid and western Valley. 

[jaxjagman]

EPS  12z today sends the PV going back to the pole but it's not vertically stacked,of course tho this is long range.The Euro  is flipping the QBO seemingly each day,getting closer anyways

[jaxjagman]

56 minutes ago, John1122 said:

Larry Cosgove today said he liked snow chances from the Rockies to the Apps through the first 3 weeks of January.  Said southern tracks that cut the Carolinas would be possible, didn't like I-95 corridor in a broad Rockies to Apps trough set up. Mentioned there's not going to be blistering cold, but cold enough air to work for a lot of areas west of the Apps. 

Sounds like a good set up for us, especially the mid and western Valley. 

Yeah the EPS long range keep showing a snow chance upcoming around New Years with a trough going through East Asia,i think it's to fast myself.Keeps showing it around new years,not sure the pattern is that fast,thinking around the 3rd

[Carvers Gap]

Looks like a very narrow window for snow in early Jan.  The 18z GEFS, after multiple cold runs, has flipped seasonal to warm d10-15.

i am still undecided for weeks 1.5-3.  Lean warm to quite warm right now.  But who knows.  The MJO is gonna have to get out of 6 though...

[weathertree4u]

39 minutes ago, Carvers Gap said:

Looks like a very narrow window for snow in early Jan.  The 18z GEFS, after multiple cold runs, has flipped seasonal to warm d10-15.

i am still undecided for weeks 1.5-3.  Lean warm to quite warm right now.  But who knows.  The MJO is gonna have to get out of 6 though...

Too early to start a thread for Winter 2020/2021?