January Pattern and Storm Discussion

[Cold Rain]

Euro ENS mean at 240 looks like a strong push of cold into the north central US. The east coast is still in a mild SE flow, but it looks like the US as a whole is turning colder. All usual caveats apply....

[EmersonGA]

I have a question concerning the stratospheric warming event. If it does happen what is going to stop the cold from going elsewhere. I seem to remember a SSW a few years ago or maybe last year that unleashed the cold in Europe instead of North America. Could that happen again?

[burgertime]

Verbatim NAM has light snow falling across much of TN....it also had it snowing up a storm in west TX and MX. 

[valkhorn]

Where are all the Tenn posters?

 

 

 

Most of the forecasts have been putting out low QPF or low chances of precip. It's been increasing slightly lately:

 

 

FXUS64 KMRX 021935AFDMRXAREA FORECAST DISCUSSIONNATIONAL WEATHER SERVICE MORRISTOWN TN235 PM EST WED JAN 2 2013.SHORT TERM...(TONIGHT AND THURSDAY)...WITH WEAK LOW LEVEL FLOW ANDMOISTURE LINGERING BENEATH THE INVERSION THE LOW CLOUDS OVER THEAREA HAVE HELD STUBBORNLY IN PLACE.  WHEN THE LOW CLOUDS DO BREAK UPSTILL WILL BE SOME HIGH CLOUDS OVER THE AREA...SO EXPECTCONSIDERABLE CLOUDINESS FOR MUCH OF THE NIGHT.  CLEARING SHOULDSTART WORKING IN LATER TONIGHT FROM SOUTHWEST TO NORTHEAST...THENEXPECT PLENTY OF SUNSHINE FOR THURSDAY AS SURFACE HIGH PRESSURECONTINUES TO BUILD IN ALONG WITH DRIER AIR. MAV TEMPS GENERALLY LOOKREASONABLE FOR THE SHORT TERM SO WILL STAY CLOSE..LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)...MAIN WEATHER CONCERNIS THE AMOUNT OF PHASING BETWEEN THE NORTHERN AND SOUTHERN STREAMWAVES AND EXTENT OF GULF MOISTURE RETURN INTO THE TENNESSEE VALLEYFOR SATURDAY NIGHT AND SUNDAY. GFS AND ECMWF AGREE FAIRLY WELL WITHA GOOD DEAL OF PHASING BETWEEN THE TWO SYSTEMS...BUT THE GFS IS WEAKIN RETURN OF GULF MOISTURE. THE ECMWF AND NAM MODELS SHOW A GOODDEAL MORE MOISTURE/ISENTROPIC LIFT AND ASSOCIATED PRECIPITATIONMOVING NORTHEAST INTO THE TENNESSEE VALLEY SATURDAY NIGHT AND SUNDAY.SINCE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE PHASING OF THETWO WAVES...I PREFER GOING WITH THE HIGHER POPS. INTERESTING THATTHE GFS POPS ARE IN THE 30S AND 40S...BUT SHOW LITTLE IN THE WAY OFQPF. LATER SHIFTS WILL LIKELY HAVE TO BUMP UP THE POPS.THE TEMPERATURE PROFILE SHOWS A MIX BAG OF SNOW..SLEET..RAIN ANDPOSSIBLY FREEZING RAIN WITH THIS SYSTEM. SINCE DEWPOINTS WILL BEINITIALLY QUITE DRY..A GOOD DEAL OF EVAPORATIVE COOLING EXPECTEDWHICH WILL HELP COOL COLUMN.UPPER TROUGH LIFTS OUT FOR SUNDAY NIGHT AND MONDAY WITH RIDGING BOTHSURFACE AND ALOFT FOR THE REMAINDER OF THE EXTENDED. ANOTHER SYSTEMMAY BEGIN TO PULL MOISTURE BACK INTO THE FORECAST FOR MONDAY...BUTWILL KEEP DRY FOR NOW.

 

I haven't looked at the Euro lately, but the GFS doesn't look all that good, and it looks very dry for that time period. If the moisture can get there, then we'll get some snow. But we need good precip rates to get any accumulation in the valley.

[valkhorn]

Verbatim NAM has light snow falling across much of TN....it also had it snowing up a storm in west TX and MX. 

 

Doesn't look like it here:

 

 

 

 

I checked a ptype output and it has very light rain. There might be some cooling of the air column due to low dewpoints but this doesn't look like much.

[burgertime]

Yep looks like it's mainly contained to north eastern TN. If it could get a little heavier then my earlier statement would probably be correct. I just quickly looked at SV maps. 

[valkhorn]

Yep looks like it's mainly contained to north eastern TN. If it could get a little heavier then my earlier statement would probably be correct. I just quickly looked at SV maps. 

 

Northeast TN has elevation to its advantage. It's typically 1500 to 2500 feet, generally at or a little higher than the Cumberland Plateau.

[Poimen]

Surprised there's not more chatter on the 18Z GFS even if it doesn't show any precip where it counts.

 

[Jonesing for a chase]

Beat me to it.  Anyway we can get that last shortwave to trend even stronger?  if so then someone in Central -eastern NC may have a shot

[gritsnc]

I just wanted to chime in and say that I've spent the past week going through old family photos and videos from 1998 to now. Almost all of the pictures and videos that I have of snow are from the month of February. So don't anyone give up yet. There is still hope.

[DaculaWeather]

I have a question concerning the stratospheric warming event. If it does happen what is going to stop the cold from going elsewhere. I seem to remember a SSW a few years ago or maybe last year that unleashed the cold in Europe instead of North America. Could that happen again?

 

The one we had last year was a Minor SSW. This event (already underway) is expected to be a Major SSW. A Major occurs when the westerly winds at 60N and 10hPa reverse and become easterly. A complete disruption of the polar vortex will occur and the vortex will either be split into pieces and/or displaced from its normal location over the pole.  It's looking like a piece lands over the US.

In the first link below, as you go though the frames for the 30 and 10hPA, you can see the vortex split. I've been watching and as the hours get closer, so does the split. Scrolling down, you can see the winds have already started slowing and you can see they are forecast to reverse. A little further down that page, notice the winds shifting from the equator to the poles.  All good signs so far. 

 

I have several pages all related to the strat temps and heights.

http://www.daculaweather.com/4_stratosphere_temp.php

http://www.daculaweather.com/4_stratosphere_height.php

http://www.daculaweather.com/4_stratosphere_temp_ecmwf.php

[dsaur]

For some reason that actually made sense...LOL.

 

Uh,oh....you may have Tony Syndrome,  Tony.  When things like this start making sense, is all down hill after, lol.  So sorry!

  The 18z is a great example.  I've got a nose of 0 line finally finding north Ga.  with some maybe system rain going underneath.... the push of cold air, from a pretty good high just w of New England.  Goofy says the low, if there is an actual low to form, will precede the push of cold from the high, if there really is a high.  Via extrapolation one could say, the high will not be so strong, the rain will not be so suppressed, and I'll get rain this weekend, followed by cooling.

  Now the virtual Goofy will perhaps come in with a map soon saying the cold air will be colder, the high lower, the rain further north, with a chance for phasing and possible wintry weather, in myb, where it is most important for it to be....but, by extrapolation, I can assume this will be virtual snow, and virtually useless, lol.  T

[GaWx]

Well we can't, the GFS has stunk all winter in the day 7+ range, ask GaWx....all I know is that next week is going to be delightful. Last winter was the first time that I remember where my grass actually grew in January and I had to cut it, we might get that chance this winter...

Like clockwork, the 18Z Goofy is significantly warmer than the 12Z Goofy during the 11-15 day in the SE. The cold 6-10 and 11-15 runs, such as the 12Z 11-15, have rarely been verifying since Oct., when two runs actually gave KATL a tie for the alltime Oct. cold of 28 F. They have yet to even reach 29 as of 1/2! Being that there is a cold bias, the 11-15 day cold has little chance of verifying while the cold only grazing the SE such as is shown by the 18Z 11-15 has a much better shot. Take the cold model runs with a grain as they have turned out to be mirages on numerous occasions in recent months. Even the few very cold Euro 6-10's have not verified. Don't be a sucker, folks.

[calculus1]

Like clockwork, the 18Z Goofy is significantly warmer than the 12Z Goofy during the 11-15 day in the SE. The cold 6-10 and 11-15 runs, such as the 12Z 11-15, have rarely been verifying since Oct., when two runs actually gave KATL a tie for the alltime Oct. cold of 28 F. They have yet to even reach 29 as of 1/2! Being that there is a cold bias, the 11-15 day cold has little chance of verifying while the cold only grazing the SE such as is shown by the 18Z 11-15 has a much better shot. Take the cold model runs with a grain as they have turned out to be mirages on numerous occasions in recent months. Even the few very cold Euro 6-10's have not verified. Don't be a sucker, folks.

 

Sir, I really do respect all your stats, but I disagree with your analysis in this case.  Here's hour 252 on the 18Z GFS at 850 mb.  Looks quite chilly to me during the same time frame as those maps of the same time frame last night.  The cold seems to come and go on this run, but I'm not too worried.  It's just something out there to watch for curiosity's sake.

 

Oh, and in reference to the bolded, I choose to take every model run with a huge grain of salt (not just the cold ones), because they really don't know what's going to happen in the future.  That's the fun of it.

 

[GaWx]

Sir, I really do respect all your stats, but I disagree with your analysis in this case. Here's hour 252 on the 18Z GFS at 850 mb. Looks quite chilly to me during the same time frame as those maps of the same time frame last night. The cold seems to come and go on this run, but I'm not too worried. It's just something out there to watch for curiosity's sake.

Oh, and in reference to the bolded, I choose to take every model run with a huge grain of salt (not just the cold ones), because they really don't know what's going to happen in the future. That's the fun of it.

1) Yes, that's a cold map. However, you accidentally posted the 0Z GFS' 252 hour map. The 18Z 252 hour map is actually quite warm with ~+12 C at 850 for Atl and Rdu ahead of a cutting storm producing rain with mild temp.'s. Also, it never gets that cold behind it (cools only to near normal for the most part) as the core of the cold stays far away since it moves eastward rather than plunging down.

2) Of course, one should take with a grain all runs, especially past day seven. However, my point is that the cold runs should be taken with a bigger grain as they're the ones that have had a lot of trouble even verifying closely. I don't feel warm runs after day seven need to be taken with quite as big a grain as they have largely been verifying much better overall.

[calculus1]

1) Yes, that's a cold map. However, you accidentally posted the 0Z GFS' 252 hour map. The 18Z 252 hour map is actually quite warm with ~+12 C at 850 for Atl and Rdu ahead of a cutting storm producing rain with mild temp.'s. Also, it never gets that cold behind it (cools only to near normal for the most part) as the core of the cold stays far away since it moves eastward rather than plunging down.

2) Of course, one should take with a grain all runs, especially past day seven. However, my point is that the cold runs should be taken with a bigger grain as they're the ones that have had a lot of trouble even verifying closely. I don't feel warm runs after day seven need to be taken with quite as big a grain as they have largely been verifying much better overall.

 

1.     I have more trouble with Allan's site than I can manage, apparently.  I click on 18Z GFS and it takes me to 00Z GFS.  I just tested it again to check.  After about the third time it finally went to 18Z, but his site only has maps up to 228 currently.  Something buggy on his site right now, it seems (or maybe it's just user error!).  I was able to access the full 18Z run on the NCEP website though, and you were right.  My apologies.  The cold does arrive on the 18Z, but it's more around hour 300 and beyond.  Thanks for pointing out my error in such a decent manner.

 

2.  The other reason that we don't have to treat warm runs of the GFS with kid gloves is that everyone is happy if they are proven wrong.  I think we tend to remember the misfires on the progged cold runs more than the misfires on the progged warm runs because many are severely upset when the cold doesn't verify versus pleasantly surprised if the warm doesn't verify.  A lot of what we remember and take note of has to do with our emotional response from the experience.

[GaWx]

1. I have more trouble with Allan's site than I can manage, apparently. I click on 18Z GFS and it takes me to 00Z GFS. I just tested it again to check. After about the third time it finally went to 18Z, but his site only has maps up to 228 currently. Something buggy on his site right now, it seems (or maybe it's just user error!). I was able to access the full 18Z run on the NCEP website though, and you were right. My apologies. The cold does arrive on the 18Z, but it's more around hour 300 and beyond. Thanks for pointing out my error in such a decent manner.

2. The other reason that we don't have to treat warm runs of the GFS with kid gloves is that everyone is happy if they are proven wrong. I think we tend to remember the misfires on the progged cold runs more than the misfires on the progged warm runs because many are severely upset when the cold doesn't verify versus pleasantly surprised if the warm doesn't verify. A lot of what we remember and take note of has to do with our emotional response from the experience.

Don't worry about it. I make careless errors often. The other day I got the two post New Year's systems mixed up in a post about one CMC run. It was a stupid error although I did admit the error once I discovered it. Then I initially accidentally left off 1956-57 in my thread about warm December analogs being encouraging for late Jan.- March. It took a question from Psalm about the lack of analogs between 1937 and 1987 to get me to realize I missed one analog.

Regarding the GFS, I truly believe it has been having a cold bias overall in recent months based just on memory and the many posts I've made about it (Wow's favorite, the "Lucy" references ). Also, a paid wx provider I use has been talking about this cold bias a good bit and actually has been showing the data to prove it. The bias has been so bad that this provider has purposely been fading the colder GFS runs and has still often verified too cold! So, I can assure you that my cold bias posts haven't been just based on my recollection of GFS runs.

[GaWx]

The well-respected Stu Ostro just posted an article at a website about the GFS cold bias. So, for those readers who don't want to take my word for it and/or think I'm making too big a deal about it, read what Mr. Ostro says (this is NOT the paid wx provider I use who has also emphasized the GFS cold bias):

http://www.wunderground.com/blog/stuostro/show.html?entrynum=20

Edit...Per Stu:

"It's been my (and I'm not the only one) anecdotal impression that in recent winters the GFS has had a bias in the Day 10-16 time frame of frequently overdoing the degree (pun intended) of cold air coming south of the border when it has shown extreme Arctic outbreaks."

[strongwxnc]

Larry, Thanks for posting this. It was a great read.

The well-respected Stu Ostro just posted an article at a website about the GFS cold bias. So, for those readers who don't want to take my word for it and/or think I'm making too big a deal about it, read what Mr. Ostro says (this is NOT the paid wx provider I use who has also emphasized the GFS cold bias):

http://www.wunderground.com/blog/stuostro/show.html?entrynum=20

 

 

[Southern Track]

Interesting read on the stratospheric warming.

http://theweathercentre.blogspot.com/2013/01/multiple-stratospheric-warmings-confirm.html

[dsaur]

1.     I have more trouble with Allan's site than I can manage, apparently.  I click on 18Z GFS and it takes me to 00Z GFS.  I just tested it again to check.  After about the third time it finally went to 18Z, but his site only has maps up to 228 currently.  Something buggy on his site right now, it seems (or maybe it's just user error!).  I was able to access the full 18Z run on the NCEP website though, and you were right.  My apologies.  The cold does arrive on the 18Z, but it's more around hour 300 and beyond.  Thanks for pointing out my error in such a decent manner.

 

2.  The other reason that we don't have to treat warm runs of the GFS with kid gloves is that everyone is happy if they are proven wrong.  I think we tend to remember the misfires on the progged cold runs more than the misfires on the progged warm runs because many are severely upset when the cold doesn't verify versus pleasantly surprised if the warm doesn't verify.  A lot of what we remember and take note of has to do with our emotional response from the experience.

 

Don't worry about it. I make careless errors often. The other day I got the two post New Year's systems mixed up in a post about one CMC run. It was a stupid error although I did admit the error once I discovered it. Then I initially accidentally left off 1956-57 in my thread about warm December analogs being encouraging for late Jan.- March. It took a question from Psalm about the lack of analogs between 1937 and 1987 to get me to realize I missed one analog.

Regarding the GFS, I truly believe it has been having a cold bias overall in recent months based just on memory and the many posts I've made about it (Wow's favorite, the "Lucy" references ). Also, a paid wx provider I use has been talking about this cold bias a good bit and actually has been showing the data to prove it. The bias has been so bad that this provider has purposely been fading the colder GFS runs and has still often verified too cold! So, I can assure you that my cold bias posts haven't been just based on my recollection of GFS runs.

 

  People, I hope all will read this exhange.  A polite, respectful, conversation between adults, a couple of my favorite posters, over a mistaken assumption, which most disagreements on the board are..  No flaming, no ugly, snide remarks, personal attacks, or general disagreeability.  This is how it's done, by professionals, or folks who try to be.  It makes for pleasant reading, an oasis, as it were.

  Ok...thanks for the pause...back to the petty bickering, lol.  Tony

[Cold Rain]

Just out of curiosity, who has been arguing that the GFS does not have a cold bias? I thought that was a well known fact. But there seem to be a great number of posts on that topic as if there has been a broad disagreement about it. Maybe I've just missed all the pro-GFS long range stuff, though.

[tonysc]

Uh,oh....you may have Tony Syndrome,  Tony.  When things like this start making sense, is all down hill after, lol.  So sorry!

  The 18z is a great example.  I've got a nose of 0 line finally finding north Ga.  with some maybe system rain going underneath.... the push of cold air, from a pretty good high just w of New England.  Goofy says the low, if there is an actual low to form, will precede the push of cold from the high, if there really is a high.  Via extrapolation one could say, the high will not be so strong, the rain will not be so suppressed, and I'll get rain this weekend, followed by cooling.

  Now the virtual Goofy will perhaps come in with a map soon saying the cold air will be colder, the high lower, the rain further north, with a chance for phasing and possible wintry weather, in myb, where it is most important for it to be....but, by extrapolation, I can assume this will be virtual snow, and virtually useless, lol.  T

 

LOL.....this Tony feels your pain Tony. I have to tell you that these models and boards of today are very interesting to say the least and I guess I'm glad we have them, but I have to say that sometimes I almost wish it was like many years ago when we weren't able to come on a computer and follow this stuff way ahead like we do now. At least we had hope in the backs of our minds then without being shot down right after it popped into our minds. I do like being able to follow these trends here but sometimes I long for the time that we couldn't do it.

[Poimen]

Interesting read on the stratospheric warming.

http://theweathercentre.blogspot.com/2013/01/multiple-stratospheric-warmings-confirm.html

That's a great read. It's a shame we might have to wait until the last full week of January to get sustained cold but I'll take it. Even more interesting is his comparison of this event to the PV collapse of 1985.

[Southern Track]

That's a great read. It's a shame we might have to wait until the last full week of January to get sustained cold but I'll take it. Even more interesting is his comparison of this event to the PV collapse of 1985.

I agree. A ton of information but he explained it very clearly.

[WilkesboroDude]

I don't think this will last forever...buy hey...if we can't get winter weather why not warm up?

[valkhorn]

I agree. A ton of information but he explained it very clearly.

 

Jan 1985 was BRUTAL for east TN. It was also something that probably won't be repeated again for a very long time. Not only was there a good polar vortex over us, there was a good bit of snowpack to send the temps plummeting.

 

We hit -24F here in Knoxville with a high one day below zero. That's unbelievable cold for here. There were no obs for the Smokys but with the snow they had they were probably approaching -40F up there.

[Southern Track]

Jan 1985 was BRUTAL for east TN. It was also something that probably won't be repeated again for a very long time. Not only was there a good polar vortex over us, there was a good bit of snowpack to send the temps plummeting.

We hit -24F here in Knoxville with a high one day below zero. That's unbelievable cold for here. There were no obs for the Smokys but with the snow they had they were probably approaching -40F up there.

I remember it vividly. I'm pretty sure it was the only time we had lows below zero in the Upstate of SC in my lifetime. Just amazing cold.

[calculus1]

I don't think this will last forever...buy hey...if we can't get winter weather why not warm up?

OK, so the way that I read this map is that, for the majority of NC, the mean temp during the 6-10 day time frame of January 8-12 averages out to be somewhere between 40 F and 45 F, according to climatology.  The dark red shading covering a majority of NC indicates that, according to NOAA, there is a 60% chance that we will be warmer than normal for that period (a mean temp of 40-45 F).  Technically speaking, that means we could be destined for days with the mean temp at 46 F.  Not exactly a torch, necessarily.

 

By the way they are constructed with bright red colors, these maps give the impression that we need to get ready for August-like temperatures.  For instance, it appears that Ohio will be roasting during this same time frame (according to the volcano red covering most of the state), but their normal mean temp range (from this same map) is between 25-35 F depending on what part of Ohio you reside in.  So, if you lived in Cleveland, for example, you could be destined for above normal temperatures which might equate to a mean temp of 30 F.  Lots of snow could still fall for them and days could be quite chilly over that period, all other things being equal.

 

Anyway, all this to say, that just because we have some dark reds over us, it doesn't mean that we're going to be breaking out the shorts and tank tops in a week.  Perhaps that will be the case, but this map alone only demonstrates that NOAA has pretty high confidence in a good portion of the east being warmer than "normal," whatever that "normal" happens to be.

 

(FYI:  I am not making any type of forecast here or predicting any conditions.  I'm just interpreting the map as its own stand-alone entity and discussing some of the possible implications.)

[Met1985]

Looks like with this cold shot coming in around the 7th the mountains may see another decent upslope event.