Where we're at, where we're going

[usedtobe]

Euro ensemble spread is very wide beginning at 144 hours and by 240 they show almost very possible solution. In other words, we are in a pattern where trying to predict specifics beyond day 4 is pretty much hopeless.

Thanks, for the update on the euro ensemble spread. I can't say I'm surprised though I would be surprised to see accumulating snow by dec 7th at dca. Farther north, who knows. I'm actually somewhat encouraged by the pattern with the nice block that is showing up on the means. I think it might open the door for some opportunities but as you say, at such long time ranges saying anything specific is pretty foolish.

[Yes_Probably_Maybe_No]

Anyone know of any preceding or succeeding snowstorm with a similar block to what the GFS is showing (like at hour 168) regarding the strength and position of the NAO block (55/50)?

[HM]

Well, it is good to see things coming together and verifying. The late Nov -EPO/NAO development is working out well and it delivered the coldest outbreak since 1985 to the West. At a time of "weakened forcing" is when you will get your meridional flows and blocking. As the +AAM anomaly propagates into the Mid Latitudes (with the actual cause being the +MTs that will take place), a new surge of +h85 winds will start propagating eastward through Indonesia and the -h2 winds will intensify. The models are now beginning to catch on to the idea of a new MJO wave but they are still confused/weak because the signal is weak. When the circulation changes across the Himalayas, the h2 winds will respond across the IO and that will get the MJO signal out of the toilet again.

The word is "retrogression" for the N PAC through the first half of December and this is favorable for a PNA pattern to take place (Aleutian High-GOA low-west ridge). As the MJO signal intensifies and the +AAM peaks out and -dAAM/dt starts up, the pattern will likely break down and head warm.

I agree with others that Dec 4-5 and then later that following week are definite winter threats.

[usedtobe]

Well, it is good to see things coming together and verifying. The late Nov -EPO/NAO development is working out well and it delivered the coldest outbreak since 1985 to the West. At a time of "weakened forcing" is when you will get your meridional flows and blocking. As the +AAM anomaly propagates into the Mid Latitudes (with the actual cause being the +MTs that will take place), a new surge of +h85 winds will start propagating eastward through Indonesia and the -h2 winds will intensify. The models are now beginning to catch on to the idea of a new MJO wave but they are still confused/weak because the signal is weak. When the circulation changes across the Himalayas, the h2 winds will respond across the IO and that will get the MJO signal out of the toilet again.

The word is "retrogression" for the N PAC through the first half of December and this is favorable for a PNA pattern to take place (Aleutian High-GOA low-west ridge). As the MJO signal intensifies and the +AAM peaks out and -dAAM/dt starts up, the pattern will likely break down and head warm.

I agree with others that Dec 4-5 and then later that following week are definite winter threats.

To me the 5th is too early, I could see it from maybe dec 7 through the 10th or 11th for a threat.

[Srain]

I am aware the Wes and HM are focusing their attention along the EC, but the signals are raising an eyebrow in the Southern Plains as well. Great discussion folks.

Norman, OK...

THE COLD AIR LATER IN THE WEEK WILL NEED TO BE MONITORED THOUGH...

AS THERE ARE SIGNS OF A PATTERN CHANGE THAT COULD BRING WINTER

PRECIP TO THE AREA EARLY THE FOLLOWING WEEK. BOTH THE GFS AND THE

ECMWF AMPLIFY AN UPPER RIDGE OVER FAR WESTERN N AMERICA AND

ESTABLISH A LOW OVER NEW ENGLAND. BOTH ALSO HAVE SOME SORT OF

SYSTEM WORKING THROUGH THE SW STATES INTO THE S PLAINS AROUND

NEXT MON-TUE... BY WHICH TIME THEY BOTH ALSO HAVE A SIZEABLE

CANADIAN SFC HIGH SUPPLYING COLD AIR TO MUCH OF THE CONUS E OF THE

ROCKIES. BOTH MODELS SHOW ACCUMULATING SNOW INTO OK MON-TUE - 4-9

INCHES OF IT IN THE CASE OF THE ECMWF. THERE WILL LIKELY BE

SEVERAL SIGNIFICANT SWINGS IN THE MODELS BETWEEN NOW AND THEN...

SO IT IS WAY WAY TOO EARLY TO EVEN TRY TO NAIL DOWN ANY OF

THIS. BUT IT WILL BE WORTH WATCHING IN LATER MODEL RUNS AS WE ARE

ABOUT DUE FOR SOME SORT OF WINTER WEATHER.

Dallas/Ft Worth...

BEYOND NEXT WEEKEND WE WILL HAVE TO WATCH FOR A PERIOD OF COLDER

THAN NORMAL TEMPERATURES. A BLOCKING HIGH IS FORECAST TO DEVELOP

SOUTH OF GREENLAND AND LONGWAVE TROUGHS SHOULD BECOME STATIONARY

ROUGHLY ALONG/OFF EACH COAST OF NORTH AMERICA. THIS SHOULD CREATE

A FAVORABLE ENVIRONMENT FOR A SURFACE HIGH ACROSS CANADA AND THE

US TO GROW IN SIZE/STRENGTH EARLY NEXT WEEK AND SPRAWL SOUTHWARD

INTO THE US. WHILE THIS PATTERN IS NOT LIKELY TO PRODUCE ANY

BITTER OR RECORD COLD HERE...IT IS FAVORABLE FOR A QUIET AND

GRADUAL INFILTRATION OF POLAR AIR FROM THE NORTH AND NORTHEAST

OVER THE COURSE OF A FEW DAYS. THE ECMWF FORECASTS THIS DECLINE IN

TEMPS TO BEGIN WITH A FRONT ON SATURDAY...WHILE THE GFS WAITS

UNTIL MONDAY. EVEN THOUGH THE BROADER UPPER LONGWAVE PATTERN

REMAINS STATIONARY...MODELS DO SHOW AN ACTIVE WEST-EAST JET

ACROSS THE CONUS AND ARE STRUGGLING WITH HOW TO RESOLVE SHORTWAVE

ENERGY COMING IN FROM THE PACIFIC. GFS/ECMWF/GEM AND VARIOUS

ENSEMBLES ARE DISPLAYING ENORMOUS SPREAD BY EARLY NEXT WEEK...AND

THUS TOO EARLY TO DETERMINE WHETHER ANY PRECIPITATION WILL RESULT.

[Amped]

ECMWF shows a Legitamate southern stream shortwave with height falls moving east FWIW. Too bad those things tend to cut off over the SW deserts in Nina years.

[Cyclonicjunkie]

Jb predicts a white Christmas for most of the nation including i95

That's a B....R....O....A....D statement.

[Amped]

Check out this retrodigging low in the north atlantic. It moves from 45N all the war down to 30N. Strange.

http://www.meteo.psu.edu/~gadomski/GFSTROPATL_12z/gfsloop.html

[Lee]

Tip: click inside this box to load the editor

[Amped]

ECMWF shows a Legitamate southern stream shortwave with height falls moving east FWIW. Too bad those things tend to cut off over the SW deserts in Nina years.

http://www.meteo.psu.edu/~gadomski/ECMWF0.5_12z/ecmwfloop.html

Bingo!

[wxmx]

ECMWF shows a Legitamate southern stream shortwave with height falls moving east FWIW. Too bad those things tend to cut off over the SW deserts in Nina years.

[Srain]

[tacoman25]

Well, it is good to see things coming together and verifying. The late Nov -EPO/NAO development is working out well and it delivered the coldest outbreak since 1985 to the West. At a time of "weakened forcing" is when you will get your meridional flows and blocking. As the +AAM anomaly propagates into the Mid Latitudes (with the actual cause being the +MTs that will take place), a new surge of +h85 winds will start propagating eastward through Indonesia and the -h2 winds will intensify. The models are now beginning to catch on to the idea of a new MJO wave but they are still confused/weak because the signal is weak. When the circulation changes across the Himalayas, the h2 winds will respond across the IO and that will get the MJO signal out of the toilet again.

Coldest since 1985, and third coldest of the past 100 years behind 1955.

[nzucker]

Coldest since 1985, and third coldest of the past 100 years behind 1955.

Despite the arctic outbreak, the West will probably finish the month of November around average, given that the next few days should be chilly again:

[HM]

To me the 5th is too early, I could see it from maybe dec 7 through the 10th or 11th for a threat.

I agree that the second one before the pattern shifts is the one to watch and everyone seems to be on top of this one. I would stress caution when the pattern is tainted with "La Niña tendency" but it does appear everything might come together here. The ECMWF solution is bogus and the typical bias.

After this though, things are looking warm and this has support from the forcing. This is why I stressed December might look odd, temp anomaly-wise. If the coldest anomalies end up in the far west and Southeast states with warm across the northern-tier, it would look more like an El Niño than anything else. We'll see because like I said previously...there will be 3 general pattern modes this month and it might not work out quite like that and more like a hybrid.

[nzucker]

I agree that the second one before the pattern shifts is the one to watch and everyone seems to be on top of this one. I would stress caution when the pattern is tainted with "La Niña tendency" but it does appear everything might come together here. The ECMWF solution is bogus and the typical bias.

After this though, things are looking warm and this has support from the forcing. This is why I stressed December might look odd, temp anomaly-wise. If the coldest anomalies end up in the far west and Southeast states with warm across the northern-tier, it would look more like an El Niño than anything else. We'll see because like I said previously...there will be 3 general pattern modes this month and it might not work out quite like that and more like a hybrid.

Do you mean the MJO will be moving into Phases 1-2, supporting the idea of a warm mid-December, HM?

Don't you think the Northern Tier would be cold if we got a Rex block configuration with ridging over the Yukon/eastern AK? I could see some cold anomalies persisting for a while in the Upper Midwest and Eastern Plains with the PV sitting over Canada and a double block forcing pieces of it towards the CONUS...that'll eventually let up but how much of a cold anomaly will we have created? I agree that California and the Pacific Northwest will probably end up well below average this month with the cut-off drifting about there.

When do you see the pattern changing to warm? Will the NAO eventually go positive as the GFS and ECM have been showing in the long-range?

[HM]

Coldest since 1985, and third coldest of the past 100 years behind 1955.

Yes this cold was well advertised and that will set the stage for a strange December. It doesn't look very 2007/2008 right now. I could see a 1954/1975 type of anomaly distribution for December, despite the La Niña...

[HM]

Do you mean the MJO will be moving into Phases 1-2, supporting the idea of a warm mid-December, HM?

Don't you think the Northern Tier would be cold if we got a Rex block configuration with ridging over the Yukon/eastern AK? I could see some cold anomalies persisting for a while in the Upper Midwest and Eastern Plains with the PV sitting over Canada and a double block forcing pieces of it towards the CONUS...that'll eventually let up but how much of a cold anomaly will we have created? I agree that California and the Pacific Northwest will probably end up well below average this month with the cut-off drifting about there.

When do you see the pattern changing to warm? Will the NAO eventually go positive as the GFS and ECM have been showing in the long-range?

The MJO is practically in those phases now, despite the raw value being in the toilet. There isn't a solid juxtaposition yet of the -h2 winds and +h85 winds; however, the h85 winds show a solid phase 1-2 response. I suspect a growing signal into phase 3-4, similar to October, as we move into December which will ultimately bring on the warm-up mid-month.

As for the EPO, those days are over for a while. It looks like a solid +EPO type of pattern but with the low displaced SW of Alaska, aiding in downstream ridging throughout the W-C States. This may help keep the East from torching but west of the Appalachians is a different story.

[tombo82685]

The MJO is practically in those phases now, despite the raw value being in the toilet. There isn't a solid juxtaposition yet of the -h2 winds and +h85 winds; however, the h85 winds show a solid phase 1-2 response. I suspect a growing signal into phase 3-4, similar to October, as we move into December which will ultimately bring on the warm-up mid-month.

As for the EPO, those days are over for a while. It looks like a solid +EPO type of pattern but with the low displaced SW of Alaska, aiding in downstream ridging throughout the W-C States. This may help keep the East from torching but west of the Appalachians is a different story.

ugh, better enjoy the next two weeks it sounds like before things get fugly

[HM]

ugh, better enjoy the next two weeks it sounds like before things get fugly

Yes but has the potential to end with a bang later next week. Like I said to Wes, that solution on the ECMWF is crap and I suspect the wave will come out, despite the upstream ridging. The ECMWF ensembles seem to favor bringing the wave out.

[tombo82685]

Yes but has the potential to end with a bang later next week. Like I said to Wes, that solution on the ECMWF is crap and I suspect the wave will come out, despite the upstream ridging. The ECMWF ensembles seem to favor bringing the wave out.

hm is there any chance in hanging onto the cold and snow threats? I mean is there anything looking legitimately possible?

[HM]

hm is there any chance in hanging onto the cold and snow threats? I mean is there anything looking legitimately possible?

Yes...the focus of the warmth will be across the northern-tier and W-C states, similar to an El Niño composite. This means the cool anomalies may focus across the Southeast. Occasionally, waves will drop down from the ridge and potentially cause some wx with marginal air. But as far as Arctic Air, that is going to be hard to come by with this shift. A North Atlantic ridge will go up periodically, too, which may help aid in slowing things down across the eastern third...but not quite a true -NAO.

[tombo82685]

Yes...the focus of the warmth will be across the northern-tier and W-C states, similar to an El Niño composite. This means the cool anomalies may focus across the Southeast. Occasionally, waves will drop down from the ridge and potentially cause some wx with marginal air. But as far as Arctic Air, that is going to be hard to come by with this shift. A North Atlantic ridge will go up periodically, too, which may help aid in slowing things down across the eastern third...but not quite a true -NAO.

thanks for the info, i and im sure everyone else appreciates it greatly.

[tacoman25]

Despite the arctic outbreak, the West will probably finish the month of November around average, given that the next few days should be chilly again:

Yeah, the huge blowtorch the first 1/3 of the month created some anomalies that were tough to overcome....but it does look like quite a few places will end up finishing the month below normal.

The effects of the radical pattern change since the middle of the month are clear.

[nzucker]

The MJO is practically in those phases now, despite the raw value being in the toilet. There isn't a solid juxtaposition yet of the -h2 winds and +h85 winds; however, the h85 winds show a solid phase 1-2 response. I suspect a growing signal into phase 3-4, similar to October, as we move into December which will ultimately bring on the warm-up mid-month.

As for the EPO, those days are over for a while. It looks like a solid +EPO type of pattern but with the low displaced SW of Alaska, aiding in downstream ridging throughout the W-C States. This may help keep the East from torching but west of the Appalachians is a different story.

I'm not sure I'd call this a classic +EPO...sure there's a GoA low but look at how the GFS is making it into a Rex block over Yukon, brining the arctic air south:

Last night's 0z ECM also had this pattern, but even more exaggerated. This would be a very cold regime developing for the Eastern Plains and Upper Midwest, as well as the East Coast:

I can see why you're talking about warmth later in the month but I think there may be some arctic air attacking the CONUS before then. Not sold on a torch either by any means.

[HM]

I am talking about mid-month man.

[nzucker]

Here were the analogs HM cited:

Not sure I like either of these analogs for this December as I envision the Midwest and Plains being much colder, but we'll see how it plays out. HM certainly has a great handle on the pattern so far although I do lean a bit colder for Northern New England and the Midwest. Still not convinced we won't see an arctic outbreak if the NAO teams up with the Rex block over the Pacific to send the PV south towards the CONUS.

[nzucker]

I am talking about mid-month man.

I just wonder how long it will take to evaporate that ridge forming in AK North Slope, which tends to spill a lot of cold air into the Plains and Upper Midwest, making it hard to end up with the anomalies positioned like 1954/1975...it seems like the NAO/AO block is doggedly persistent despite the strong La Niña.

I was thinking something like this:

Seeing how the long-range pattern looks, I might shift the 1955 map so that the warmest anomalies are more towards the Southern Plains and California is cooler. This would be somewhat in line with what HM said although I'm still riding the La Niña gradient of the north being colder than the south.

[HM]

You could be right, especially if the pattern takes longer to switch and/or the MJO doesn't become as coherent as I think it will be. Then in that case, the NAO will continue to stay lower and the cold will continue like the beginning of the month. I just think this wave is coming and will bring a warm-up. Obviously we agree on the East, but the area we disagree is the northern Plains.

[Hoosier]

Yeah, the huge blowtorch the first 1/3 of the month created some anomalies that were tough to overcome....but it does look like quite a few places will end up finishing the month below normal.

The effects of the radical pattern change since the middle of the month are clear.

Hey taco, can you post the link to the site for those maps?