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Winter 2015-16 Medium-Long Range Discussion


OHweather

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GFS still hinting at potetnial troughing late next week and X-Mas week which could bring a decent chance at some LES for the Great Lakes snowbelts. 850 temps around -15 or so which should be enough to get the Lakes going with Lake temps still relatively warm. At this point i'll be happy with anything we can muster before X-Mas.

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warm

 

 

Euro is on board for some -15C 850's to make it into the region. Looks to last only about 2-3 days then we might see another decent cold shot around Christmas which the GFS says will feature lower temps and dive a little farther south as well. Would expect that second cold shot to decrease in intensity on the models as we approach it just based on seasonal trends.

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That jet retraction will be temporary. Maybe it's enough to build a ridge in the N. Pac and temporarily cool off western/central N. America but I'd expect a strong Pac jet to return sooner rather than later.

I'm starting to worry that the cool down I had in January in my winter forecast will be a bit more delayed and that the month has a whole ends up pretty mild compared to normal for most or all of us.

 

 

That is a possibility as far as January goes.  My guess would be less persistent warmth than December but there's a big gap between December type warmth and being colder than average. 

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Was just thinking the same thing today looking at things. The much derided CFSV2 has had a very good handle on the pattern this month with a long lead time back to the beginning of November. It's a bit early to have high confidence in the January forecast, but the first 11 daily runs have all been similarly locked into very warm anomalies. We really need the PV to weaken to have much of a chance to shuffle the deck to a predominantly colder pattern in January- A few seasonal days here and there aren't going to cut it and we'll need good timing to get a widespread significant snow ala 11/20-21. The CFS h7 anomalies for January are pretty much the classic strong Niño composite.

Even if January is mild, timing isn't nearly as important as it was in november. The "dead of winter" is still 7+ weeks away. The key will be getting storminess to continue. Torch is never good, but seasonably mikd can fuel a good snowstorm in mid winter. Don't get me wrong I want a cold pattern too...but it could easily go cold and dry. There are tons of unknowns out there.
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12z GFS run definitely has more cold on it than the 6z run.

Good post and good points about the Indian Ocean convection and AMT Chasmosnow. Getting that Pacific jet to slow down would help unlock cold air to the north and give it a chance to move further south from Canada's arctic.

 

Was looking at the vortex on this run and between early next week and Christmas it gets shoved off towards Europe.

High altitude ridging pushes against it coming up from eastern Russia.

 

gfs_Tz10_nhem_11.png

 

To this.

 

gfs_Tz10_nhem_30.png

 

Cross polar flow evident right before Christmas.

 

gfs_z500a_nhem_45.png

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Was just thinking the same thing today looking at things. The much derided CFSV2 has had a very good handle on the pattern this month with a long lead time back to the beginning of November. It's a bit early to have high confidence in the January forecast, but the first 11 daily runs have all been similarly locked into very warm anomalies. We really need the PV to weaken to have much of a chance to shuffle the deck to a predominantly colder pattern in January- A few seasonal days here and there aren't going to cut it and we'll need good timing to get a widespread significant snow ala 11/20-21. The CFS h7 anomalies for January are pretty much the classic strong Niño composite.

I don't think we'll be as bad as this month, but I don't see any prolonged change until the strat PV breaks down...the long range guidance is trying to hint at the process starting later this month which would maybe bring a change by late January, but if the first 2-3 weeks of the month are pretty warm a cold last week probably wouldn't erase that. Typically the Gulf of Alaska vortex tries to start retrograding in January at some point in basin wide Ninos, so we'll need to watch the location of the forcing and see if it remains centered just east of the Dateline (which is what you'd expect in a basin wide Nino) or if it tries nudging farther east, which would worry me. So far the location of the negative OLR anomalies is pretty close to where they typically are in basin wide events (and a good bit farther west than something like 82-83 and 97-98).

 

olr_hov_last180days.gif

 

You may  well be right. However that incredible  strong jet of late was partly fueled by India ocean convection which is dissapearoing and the sinking southward  Siberian high generating incredible amounts of AMT  or mountain torque.It could have been be a one off event.

 

  On any account is interesting trying to sort all of this out.I realize  El Nino signal strongest in Jan and Feb and what we have just seen may just be its opening shot.Convection east of the date line still strong and untill that stops at the very least southern US gets a strong subtropical jet.Pacific jet however sometimes has a mind of its own especialy if wave action in Asia  is inducing high amplitude flow. SSW also could disturb the classic back ground state of a strong El Nino.

 

  At least we can still speculate.Hate those flows that get locked in and show no signs of ever changing.

I suspect the mountain torque was probably responsible for the jet retraction before Thanksgiving that dumped cold into the western/central US and it is probably going to play a role coming up as the jet retracts again. I don't understand mountain torque particularly well but I believe drops in AAM caused by mountain torque result in a more retracted Asian-Pacific jet. It's mildly interesting that it's happened once (and is about to happen again) and briefly shaken up the Nino base state and disrupted the Alaskan vortex and weakened the Pac jet...we'll see if it's a trend this winter. It's worth noting the pattern has sucked balls other than these two transient cooler patterns.

 

That is a possibility as far as January goes.  My guess would be less persistent warmth than December but there's a big gap between December type warmth and being colder than average. 

Yeah I agree...my one concern is other than some attempt in late November we haven't done much to start warming/weakening the stratospheric PV which is a big component to a second half of winter flip, along with the Gulf of Alaska low retrograding towards the Aleutians. If the modeled heat flux into the stratosphere starting in a week or so comes to fruition I'd have to think we'd still be OK for a flip by late January, but it's something to watch. The Euro ensembles have apparently hinted at some improvement in the stratosphere within two weeks but for now it's pretty far off...so we'll probably have to be patient.

 

Anyways, the ensembles (and the Euro ensembles are close to this look too, maybe slightly less favorable) do try to pop some ridging in Alaska around Christmas which would at least bring a little cold into Canada...this look wouldn't be bad for the western and northern parts of the subforum with cold dumping into the west and troughing over the southwest too, but the farther south and east you go the worse this would be for snow prospects. I still think it's possible we time a system with some cooler air around Christmas but would rather be farther west than I am...we'll see.

 

gfs-ens_z500a5d_nhem_3.png

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I don't think we'll be as bad as this month, but I don't see any prolonged change until the strat PV breaks down...the long range guidance is trying to hint at the process starting later this month which would maybe bring a change by late January, but if the first 2-3 weeks of the month are pretty warm a cold last week probably wouldn't erase that. Typically the Gulf of Alaska vortex tries to start retrograding in January at some point in basin wide Ninos, so we'll need to watch the location of the forcing and see if it remains centered just east of the Dateline (which is what you'd expect in a basin wide Nino) or if it tries nudging farther east, which would worry me. So far the location of the negative OLR anomalies is pretty close to where they typically are in basin wide events (and a good bit farther west than something like 82-83 and 97-98).

 

I suspect the mountain torque was probably responsible for the jet retraction before Thanksgiving that dumped cold into the western/central US and it is probably going to play a role coming up as the jet retracts again. I don't understand mountain torque particularly well but I believe drops in AAM caused by mountain torque result in a more retracted Asian-Pacific jet. It's mildly interesting that it's happened once (and is about to happen again) and briefly shaken up the Nino base state and disrupted the Alaskan vortex and weakened the Pac jet...we'll see if it's a trend this winter. It's worth noting the pattern has sucked balls other than these two transient cooler patterns.

 

Yeah I agree...my one concern is other than some attempt in late November we haven't done much to start warming/weakening the stratospheric PV which is a big component to a second half of winter flip, along with the Gulf of Alaska low retrograding towards the Aleutians. If the modeled heat flux into the stratosphere starting in a week or so comes to fruition I'd have to think we'd still be OK for a flip by late January, but it's something to watch. The Euro ensembles have apparently hinted at some improvement in the stratosphere within two weeks but for now it's pretty far off...so we'll probably have to be patient.

 

Anyways, the ensembles (and the Euro ensembles are close to this look too, maybe slightly less favorable) do try to pop some ridging in Alaska around Christmas which would at least bring a little cold into Canada...this look wouldn't be bad for the western and northern parts of the subforum with cold dumping into the west and troughing over the southwest too, but the farther south and east you go the worse this would be for snow prospects. I still think it's possible we time a system with some cooler air around Christmas but would rather be farther west than I am...we'll see.

 

 

 

That's all I want. That's what all the models are showing too.

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lol, I know Alek likes he mild winter days. He picked the warmest time period between too cold shots.

 

At least the models don't show a non-stop temperature regime like it is now. GFS and GEM bring back the cold on Christmas or the 26th by the looks of it. Noticed on the 18z GFS, the polar vortex getting moved off the pole a little sooner.

 

Should be interesting watching the SSW.

 

gfs_Tz10_nhem_9.png

 

gfs_Tz10_nhem_26.png

 

Noticed rising heights over the pole at day 10 on the EURO too.

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Interesting conversation going on over in twitter land the past few days beteen @antmasiello and @judah47

     The debate is mostly about whether the El Nino base state or the monster strat vortex is resposible for the warm N. hemispheric anomalies of late.

 

 Seems to me both Judha Cohen and Anthony Masiello have good argumnets about what is causing the warmth but what really intrigues me is that for much of November and again now we are showing classic La Nina anomalies out side the subtropics in the N. hemisphere.

 

 With La Nina we loose the warm north, cold south split over N. America and repalce it with cold west ,warm east. 

 

   Also the trough predicted for the west Pacific in the next 15 days and the moderate ridging thru Alaska  and back towards Siberia is another strong sign the El Nino base state is being messed with.Keep this up and we will soon have a -PDO

 

Hard to find an explantion for this.

 

Indian ocean convection? Sudden collapse or weak mountain torque  coming off the Asian chain? Baroclinicity near the Asian chain of mountains usaully resutls in a strong east asian jet that charges  out  across the Pacific so that is something to look for  in anticipaiting mountain torque. Models in November predicted this very well.

 

Regardless think Cohen is right that untill we weaken the Strat. vortex over the north pole we may get short  Nina like cold spells but they won't last and over all it will be warm.

 

  Models of late seem to want stretch the polar vortex out and at least hint at a wave two pattern which usually gives us a  -AO.

 

Wait and see as they say.Can only hope that the westerly QBO is not inhibiting wave flux energy that attacks the vortex and warms it up. And also that the increased solar activity of late is not messing with the Ozone needed to increase warmth  over the pole and in the stratosphere.

 

Told my girl friend today that all  I want for Christmas is a little bit of analmous warmth at 10mb over the north pole.

 

Wishcasting I can do. Its the forecasting that gets me down!

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There's two more substantial systems on the GFS during Christmas week, but that's way out still.

 

   If you lookout far enough, (288hours) Pacific jet becomes zonal across entire country at about 35 degrees north.This knocks out the eastern ridge and would be indicative of a major change if it happens.

 

  Not good to be looking out this far but this kind of path for the mid latitude jet ought to to give hope to southern part of sub forum as well as the east coast for possible snow.

 

  El Ninos  evolve. Maye this is the next step. Is hard to believe the cold west warm east thing is going to last forever. A jet like this would bring the cold futher south and into the east which is more like what you would expect from an El Nino.

 

 

 Edit up date: 8:00am   Overnight  ensembles 0600z GFS  do not  confirm the above attempt at optimsm. Westerly flow across Canada continues.. Ensembles have been pretty consitent in prediicting continued warmth.  Untill that changes not to get excited!

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We hit 72 yesterday (a new record). Only dropped to 63 overnight. Very humid. +8.2 on the month.

It jumped to 76 in the house last evening.

Turbo-torch.

If it's any consolation, we aren't the only ones getting torched. Global Dec. temps are running about +2.5 so far.

#mustbeclimatechange
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