February/March 2020 Winter's Last Chance Thread

[Carvers Gap]

As for a large scale pattern change later this month....just kicking that around.  Notice that the MJO forecast ends about where the last head fake began.  LOL.  Still, when you look at the yellow lines(ensemble member spread), many of them are headed into cold phases.   Get the models and the MJO singing the same song(even though late winter), that is a really good sign.

[Matthew70]

28 minutes ago, Carvers Gap said:

These are fairly significant trends in the ECMF MJO as it almost makes it into phase 8.   At this point, the MJO is beginning to hint at a large scale pattern change and not just a window of opportunity.   JUST using the ECMF MJO(there is another version ECMM which is slightly less bullish which uses climatology...ECMF is just the pure ensemble run I "think").   This actually has support from both the GEFS which is likely overly amped, but headed in the same direction.  It also lends support to what John was saying earlier in the thread that once the MJO hits phase seven, it gets cold after that w a lag possibly built in.  So, the signal for cold during week 4 of February is now a bit stronger IMHO.  Let's see if it holds and trends even better.  The GEFS has been sort of correct in the higher amplitude of 5, but seems out there with high amplitude 6/7.  So, a mini-victory for the GEFS up to this point.  Either way, both the ECMF and GEFS are heading towards better phases in about ten days or sooner.  That is also supported by ensemble runs hinting at changes.  Always good to be aware that sometimes modeling can jump the gun....but thought this was worth a share.  If true, this would likely provide us with a potential window of more than just 2-3 days but counterweighted by climatology being less favorable by the day at that timeframe.  Good news to see modeling hustling out of "bad" phases of the MJO.

 

Just hope this does not mean a cold rainy spring.

[Carvers Gap]

15 minutes ago, Matthew70 said:

Just hope this does not mean a cold rainy spring.

Certainly is not a warm signal at this point.  I wouldn't put too much stock in anything outside of 3 weeks right now though.  We are getting to the time of year where the Euro starts to become human again - shoulder season.  Seems like the month of Decembers has warmed and March has cooled during the past decade.  So, a cool March would not surprise me.   If forced to make a call, I would go BN...but that is a hunch and not a forecast.  If La Nina kicks-in at some point, we will likely see a large hemispheric shift in the jet next fall...but could be earlier.  I just don't want a hot and dry summer, and I somehow can't shake the idea that might be about what we are going to get...very hot August and September.  Seems like these rainy time frames in NE TN are often followed by an almost instant turning-off of the spigot.  Though, really it has been a rainy pattern for about a year.  But I think once this rainy pattern ends, it will be abrupt.   

To clarify, I am just talking temps in terms of a potential change down the road.  Rains seems to be a constant.  Choice are warm/rainy spring or cold/rainy spring.

[PowellVolz]

Just hope this does not mean a cold rainy spring.

That’s pretty much what that means unless we get this going in the next few weeks. Climo starts working against us in about a month but that doesn’t mean snow is out of the question. Saturday in SE Tennessee is a perfect example of just getting everything timed right, even in a period where almost everything is stacked against snow.


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[John1122]

My snow season lately lasts into April. I've had far more snow in March/April than January the last several years.  I used to rarely get through March without a 3+ inch event. Its usually gone 36 hours later though. 

[PowellVolz]

My snow season lately lasts into April. I've had far more snow in March/April than January the last several years.  I used to rarely get through March without a 3+ inch event. Its usually gone 36 hours later though. 

That’s exactly right. In the right “cool” pattern, a well placed ULL can hit a home run.


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[Carvers Gap]

52 minutes ago, PowellVolz said:

That’s exactly right. In the right “cool” pattern, a well placed ULL can hit a home run.


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Systems have a lot more juice during March.  Get an active weather pattern like we have right now with some transient cold shots and things can be interesting.  

[Carvers Gap]

12z EPS looks similar to 0z which means that 0z is now less of a hiccup.  The surface is quite warm even though the 500 pattern looks good.  That has been a real pain all winter in terms of getting patterns correct.  500 patterns have not always matched the surface temp anomalies.   Sometimes surface modeling has led the way and sometimes (maybe more often) the 500 pattern has led the way.  IF that 500 MJO is correct and continues to move towards cold phase of the MJO, we should see the EPS and other modeling begin to doubled down on cold after d10.  Will be interesting to see when and if that happens.  But for now, getting a decent 500 patterns is a win after d10.

[franklin NCwx]

If we could just get some blocking for March I think we can score a few events.  Without any blocking most systems will cut.

[Carvers Gap]

1 minute ago, franklin NCwx said:

If we could just get some blocking for March I think we can score a few events.  Without any blocking most systems will cut.

Agree.  The EPS has a weak to very weak HB block late in the run.  Problem is the AK vortex is present.   Had that during the second half of January where the cold was locked out of that blocking pattern, and we had to deal with Pacific air.  That is pretty much what the EPS at 12z depicts.   Plenty of time for that to change though.  What would be nice is for that AK vortex to dislodge and get forced under that block.  

[franklin NCwx]

4 minutes ago, Carvers Gap said:

Agree.  The EPS has a weak to very weak HB block late in the run.  Problem is the AK vortex is present.   Had that during the second half of January where the cold was locked out of that blocking pattern, and we had to deal with Pacific air.  That is pretty much what the EPS at 12z depicts.   Plenty of time for that to change though.  What would be nice is for that AK vortex to dislodge and get forced under that block.  

Hopefully we can get a modest west based nao. We had that in December 2010 and the first half of January 11. In about a 40 day window that winter Franklin got over 30" with a -pna.  

[Carvers Gap]

Euro Weeklies imply the HB block does not last and reverts back to a western trough.  IMHO, we are now at the point where the Weeklies may very well struggle due to shoulder season.  Jax has a great share over in the ENSO thread about the differing looks of the MJO.  Going to be very interesting to follow the MJO over the next few days.  If the MJO continues its trend of moving towards cold phases, going to be some wild flip flopping.  Jax's article notes what many here have spoken about...the MJO has two active areas 2/3 and 5/6.  They are creating a null phase when really it is not in the null phase at all.  It is two areas of conflicting convection that the net balance results in a null.  Null to me is inactivity.  This is two areas of strong activity that are creating a false null.  To me, the Weeklies match the EPS, and then during week 3 revert to a western trough.  Really seems to me like we are just going to see strong troughs roll through every 7-8 days with varying levels of cold(some Arctic and some Pacific origin stuff).  IMHO, fairly washed out(no pun intended) look.

[Carvers Gap]

The 18z GFS(rarely disappoints) at 252 is why folks keep watching modeling.   That set-up is likely gone by the next run, but it exemplifies how this pattern can produce a storm with one of these cold shots.  Again, just an example and not the gospel at this point.  One foot for portions of Southwest Virginia on that run and a nice thump on the Plateau.   

[Mr. Kevin]

2 hours ago, Carvers Gap said:

The 18z GFS(rarely disappoints) at 252 is why folks keep watching modeling.   That set-up is likely gone by the next run, but it exemplifies how this pattern can produce a storm with one of these cold shots.  Again, just an example and not the gospel at this point.  One foot for portions of Southwest Virginia on that run and a nice thump on the Plateau.   

Carver, to me its really shocking in a way that we can't get out of this non favorable pattern for winter weather, especially with shorter wavelengths approaching soon. 

[mempho]

Hurricane PV:
Euro 10hPa wind forecast, days 7 - 10

That's incredible. It has to break down eventually...

Sent from my SM-G950U using Tapatalk

[weathertree4u]

1 hour ago, mempho said:

That's incredible. It has to break down eventually...

Sent from my SM-G950U using Tapatalk
 

Nope; at least not for another few weeks, has to wait until end of the month so that it can cause the maximum inconvenience by making March colder than normal, not cold enough for snow but just cold enough to really be a pain in A--

[Holston_River_Rambler]

I'm starting to think it's just gonna wind down over spring. It has dominated every single attack on it. 

GFS showing yet another result this AM, rolling it back toward eastern Siberia:

100, 50, and 10 mb winds at day 15. 

You can see some of the attacks on it in the 3D vortex graphics, but nothing really makes it above the lowest levels. 

[Holston_River_Rambler]

Euro control shows some troughs making it through past day 10:

and the OP dries us out from Thursday AM through next Tuesday, so some good news there. 

 

[Holston_River_Rambler]

Here's what that above 500 mb pattern on the Euro Control translates to on the surface, just showing for an option for the Euro past day 10:

Not particularly dry, but storms move in and out and the firehose is cut off as upper winds realign a bit. 

[weathertree4u]

1 hour ago, Holston_River_Rambler said:

Here's what that above 500 mb pattern on the Euro Control translates to on the surface, just showing for an option for the Euro past day 10:

Not particularly dry, but storms move in and out and the firehose is cut off as upper winds realign a bit. 

Persistence has won so far this season, hopefully will get few dry days but I would be willing bet the larger pattern will return as has so far

[Carvers Gap]

12 hours ago, Mr. Kevin said:

Carver, to me its really shocking in a way that we can't get out of this non favorable pattern for winter weather, especially with shorter wavelengths approaching soon. 

Well, we had two advisory level events last week in out sub-forum.  So, it has not been a shutout pattern for some.  Pretty remarkable given temp departures for the season.

To me looks like our next window is after the 20th.  The 14th is a very cold look, but no storm at this time.  

Lots of great discussion above regarding the PV and MJO.  

I don’t think we leave the non-favorable pattern until met winter is almost over, if that.  Last week of Feb holds some potential for cold.  My hunch is that PV will eventually break up and  part of it will dive eastward later in Feb or early March.  But who knows?  Will not help many at that range anyway.

[Carvers Gap]

Power is out right now so my pic resizing tools are limited.  The ECMF MJO continues its good trends.  The EMON(long range) is COD for most of its cycle after d10 w a run at 8 but doesn’t quite get there.  IMHO, that is a signal for a western ridge shortly after d10.  If the PV stays wound up, cold source regions may be an issue.  It is worth noting that modeling notoriously struggles at this time of year and those struggles only get worse as we approach and then enter early spring.

My guess is that we have another pattern shake-up later this month.  As has been illustrated all winter, new patterns are not always better.  We missed a real opportunity from mid-Jan to the end of Jan with a HB block.  Cold was absent and bottled up in AK.  We were able to hit on the trough in earky Feb.  Going to have a great cold front on the 14th but dry behind the front.  IMO, the time frane from the 20th to roughly March 5th is the next window.  Those windows look great at a distance but have been verifying as 48-72 hour windows.  Looks like a front may come through around the 24th, but that is a ways out there.  

As for thr PV, it could just wind down slowly.  Sea ice area is as strong as it has been in 7-8 years after record lows this pas fall.  A tight PV will do that.  Bob Chill has a graphic in the MA banter thread.   Another option is the PV could drop into one of the troughs in the northern hemisphere as it gets ragged and unstable as early spring beats it up.

Can’t stress this enough, this is the time of year where modeling is all over the place.  Wouldn’t get too invested in any look(good or bad) past d5-6.  Prob going to change. 

[snowmaker]

12 gfs has a Tennessee special just inside 200 on this run. What could go wrong? LOL! But hey, maybe it is on too something. Here's hoping for 1 good statewide winter before spring! That would be awesome considering the winter we have had overall statewide. Statewide events are hard to come by, but they have happened. Maybe at least the majority our forum wide area can hit on at least 1 more winter event.

[Carvers Gap]

8 minutes ago, snowmaker said:

12 gfs has a Tennessee special just inside 200 on this run. What could go wrong? LOL! But hey, maybe it is on too something. Here's hoping for 1 good statewide winter before spring! That would be awesome considering the winter we have had overall statewide. Statewide events are hard to come by, but they have happened. Maybe at least the majority our forum wide area can hit on at least 1 more winter event.

Indeed.  Been popping up at this time frame off an on.  Guess is the GFS is probably too strong with the cold, but something to watch as it is within the 9 day window.  

[Carvers Gap]

Anytime a front slows and the tail stalls in the GOM, has to be watched.  Sometimes that will form a wave or slp.  I remember many snowstorms when I was young where snowstorms began as rain.  With the GFS cold bias, just tough to buy that at this range...but it has been fairly consistent with a storm signal at that range.  The Euro operational is struggling with holding too much energy in the West and IMHO is causing issues after d7-8.  Also, with the MJO changing up, we may well see some wild looks on modeling if phase 8(or even close to it) is on the table.  For as bad as January was, February has had some trackable systems.  Usually if I get 1-2 snows in February that is about normal for MBY.  Right now I am at zero.  LOL.  However, others have done well so that is cool in my book.

[PowellVolz]

Anytime a front slows and the tail stalls in the GOM, has to be watched.  Sometimes that will form a wave or slp.  I remember many snowstorms when I was young where snowstorms began as rain.  With the GFS cold bias, just tough to buy that at this range...but it has been fairly consistent with a storm signal at that range.  The Euro operational is struggling with holding too much energy in the West and IMHO is causing issues after d7-8.  Also, with the MJO changing up, we may well see some wild looks on modeling if phase 8(or even close to it) is on the table.  For as bad as January was, February has had some trackable systems.  Usually if I get 1-2 snows in February that is about normal for MBY.  Right now I am at zero.  LOL.  However, others have done well so that is cool in my book.

Won’t this translate to overrunning and more likely sleet and or RZ?


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[Holston_River_Rambler]

17 minutes ago, PowellVolz said:

Won’t this translate to overrunning and more likely sleet and or RZ?

It could, but it is how we got a little snow in December, so I'm down. 

[Carvers Gap]

1 hour ago, PowellVolz said:

Won’t this translate to overrunning and more likely sleet and or RZ?


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Get a 1040+ hp parked over the top of a front that stalls...lots of options on the table I would think in an active weather pattern.  Miller A, ice storm, multi-day overrunning event, etc.  Just would depend on what side of the front we are on when it stalls.   The 12z GFS is one option which is a slp forms and runs the front as it drags through the GOM.  Another option is just cold chasing rain like this Thursday into Friday, and that is probably option 1.    Seems like I usually see ice if the cold gets trapped and then there is WAA aloft.  I suppose if the front presses south of us, the cold air presses, and the front comes back as a warm front...it could happen OR there are multiple waves on a front w a stalled frontal boundary.  Probably the biggest problem is those big 1040+ highs have been mirages on the GFS lately.  That said, this is inside of d9 so can't rule it out completely.  

[Carvers Gap]

Internet is down now but the power is back on...(remember me telling you all about them cleaning out power lines in the neighborhood...fun times).  Looks like the Euro stalls the energy in the Southwest and sends it into the Plains.  Legit possibility and also possible it is hung up.  It looked pretty close to the GFS actually, but held back the main piece of energy.  Anyway, pretty limited viewing opportunities - meaning my computer loads really slow so I am having to load one slide at a time instead of the entire run.  Good thing...not a ton to discuss so far.  LOL.

[Carvers Gap]

The 12z EPS has sped up(by about 20 hours) the eastern trough just after d10 w the first effects of the trough impacting western forum areas around 270.  As we suspected, the trough will try to lift out and another trough will attempt to reform in the West almost simultaneously.   Looks super similar to what will happen on the 14th and what occurred on the 7th.  This one rolls through on the 22nd - again almost every 7-8 days a big trough rolls through or front.  The trough on the 22nd is deeper w the AK vortex lifting out right at the end of the run...which is a good thing I think.  Lifts out and ridging from the EPO likely replaces it.  The EPS does look like a model flirting with phase 8 of the MJO at least just based on its look in NA.   I seriously doubt modeling has the pattern nailed down right now.  The Feb 14 cold front was basically missed in the LR by the EPS/Euro.  Cold air supply is notably weak for the Feb 22 trough.  Interestingly, the GFS does show some signs at 10mb late in the run of another SPV disruption, though lower levels are stout.  That does coincide with a strong WAR which precedes the eastern trough on the 22nd.  That WAR has preceded disruptions this winter and has precede strat splits in the past.