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Winter 2014-2015 Pattern Discussion Thread III


BIG FROSTY

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Fwiw, the King has a somewhat stronger 2nd Arctic high as of day 5 to the NW.

Edit: This run is not going to get the job done. That 2nd high moves offshore quickly with no good wedge and good warming. Now I know why Chris and others went to bed earlier. Night night.

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Looks like the 6z GFS came in wetter but a little warmer for the day 6/7 event. Nothing to worry about in details. The setup will vary a lot from run to run until we get within 3/4 days. RAH upped the wording a little more:

 

MEANWHILE...THE ARRIVAL
OF STRENGTHENING SOUTHERN STREAM FLOW FROM THE EAST PACIFIC WILL
THEN CAUSE AN UPPER LOW JUST WEST OF THE BAJA THIS MORNING TO SHEAR
ENE ACROSS THE SOUTHERN US...WHICH COULD SPELL WET AND/OR WINTRY
WEATHER FOR PORTIONS OF THE CAROLINAS AND VA
...AS THE ASSOCIATED
MOISTURE INTERACTS WITH THE COLD HIGH...BY SUN-MON.

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The 6Z GFS is the 2nd GFS run in a row suggesting that Arctic air at least threatens to come back down into the SE US near or just after midmonth though neither one is back to being as cold as the runs from late Fri/early Sat. This will be fun to track and could start the 2nd half quite cold as well as keep the SE in the game for an overall cold month.

One thing I've been monitoring very closely over the last few days (as a result of what I've recently learned about its pretty significant temperature correlations) is the current as well as forecasted MJO. See the link below for current, which as of now has been updated through 1/3.The 1/3 EPS and some other models suggest it will make a sharp left turn soon and head in the general direction of COD phase 6 from its supposedly current moderate phase 5. IF it actually does that, that would then set it up for a potential quite favorable for cold trek through COD 7-8-1-2, etc. So, I recommend it be followed to see if it actually makes that sharp left turn over the next few days (the most favorable scenario to cold based on history back to 1975) or if it just takes the more common counterclockwise circular trek, which would still be ok since it would leave the dreaded warmest phase, phase 5 outside of the COD, though not as favorable for cold prospects in general as the left turn option.

I'm still anxiously awaiting updates from the models. The EPS last fcast was from Saturday middayish. The GEFS hasn't updated since late December for some odd reason.

http://www.bom.gov.au/climate/mjo/

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Sunday-Monday has my interest. 6z GFS is an ice storm for parts of Carolinas for sure. At face value (which would almost certainly be too warm as modeled), GSO gets 0.45" of ZR and CLT gets 0.39"  CAE gets 0.19" of ZR by the way. 

 

This one will be a challenge, and I think all of the ranges of solutions you see on the modeling are on the table? Why? It's a very diffuse system at 500mb, so I would expect lots and lots of changes on the modeling this week. 

 

Just look at the 500mb vort off of 6z GFS, valid Sunday afternoon:

 

 

post-390-0-85797700-1420462100_thumb.png

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Sunday-Monday has my interest. 6z GFS is an ice storm for parts of Carolinas for sure. At face value (which would almost certainly be too warm as modeled), GSO gets 0.45" of ZR and CLT gets 0.39"  CAE gets 0.19" of ZR by the way. 

 

This one will be a challenge, and I think all of the ranges of solutions you see on the modeling are on the table? Why? It's a very diffuse system at 500mb, so I would expect lots and lots of changes on the modeling this week. 

 

Just look at the 500mb vort off of 6z GFS, valid Sunday afternoon:

It's had mine too.......fwiw cobb data, since this past friday, has dropped the temps at CAE from 34-35 to 31-33. It still warms us up during the events end to above freezing.......barely   :lol:     ;)      

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Favorable trends in the recent modeling for both winter storm threats and colder weather.  Much has already been posted about the 7 day ice threat as well as the impending arctic blast.  The teleconnections look pretty good with a steadily positive PNA and a falling AO and NAO in the LR.  Who knows when we'll get the kind of blocking that will be helpful to us, but given the latest operational and ensemble runs, the medium range looks pretty good, with uncertainty increasing as you go out in time...although climo and analogs suggest that mid month into Feb and possibly March looks to be our best opportunity for colder, snowier conditions.

 

I like the upcoming storm chance.  In this kind of pattern, timing needs to be darn close to perfect, but we are seeing in the modeling realistically how that can work out.  Anytime you have big highs tracking across the northern tier of the country, that should raise a flag for a period to watch for winter threat.  Anyway, I think the tide is turning on our boring winter to date.  Hopefully, enough blocking will develop to give us some legitimate snow chances as we move through the second half of met winter.  In any case, it's finally time for a signature change.

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Catching up on models this morning, I like we're getting a threat to track for the beginning of next week.  Hopefully the EURO will come on board soon.  Always nervous when it's the GFS leading the way.  It's been doing pretty good this winter though.  That and Matt East is tracking it.... :weenie:

 

Also liked the GEFS for mid month.  I'm no expert but this looks pretty good to me...big +PNA, eastern trough, -NAO and a great split flow signature.  Also generally higher heights toward the pole. Yeah the trough is a bit east but man, it's a lot better than it looked last week. 

 

SCMKcDXl.png

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6z GFS progression of p-types through the SE:

 

http://mag.ncep.noaa.gov/Image.php?image=data%2Fgfs%2F06%2Fgfs_namer_150_dom_precip_type.gif&model=gfs&area=namer&storm=&cycle=06&param=dom_precip_type&fhr=150&group=Model+Guidance&imageSize=M&ps=model&use_mins=no&preselected_formatted_cycle_date=20150105+06+UTC&scrollx=0&scrolly=0

 

http://mag.ncep.noaa.gov/Image.php?image=data%2Fgfs%2F06%2Fgfs_namer_156_dom_precip_type.gif&model=gfs&area=namer&storm=&cycle=06&param=dom_precip_type&fhr=156&group=Model+Guidance&imageSize=M&ps=model&use_mins=no&preselected_formatted_cycle_date=20150105+06+UTC&scrollx=0&scrolly=0

 

http://mag.ncep.noaa.gov/Image.php?image=data%2Fgfs%2F06%2Fgfs_namer_162_dom_precip_type.gif&model=gfs&area=namer&storm=&cycle=06&param=dom_precip_type&fhr=162&group=Model+Guidance&imageSize=M&ps=model&use_mins=no&preselected_formatted_cycle_date=20150105+06+UTC&scrollx=0&scrolly=0

 

http://mag.ncep.noaa.gov/Image.php?image=data%2Fgfs%2F06%2Fgfs_namer_168_dom_precip_type.gif&model=gfs&area=namer&storm=&cycle=06&param=dom_precip_type&fhr=168&group=Model+Guidance&imageSize=M&ps=model&use_mins=no&preselected_formatted_cycle_date=20150105+06+UTC&scrollx=0&scrolly=0

 

http://mag.ncep.noaa.gov/Image.php?image=data%2Fgfs%2F06%2Fgfs_namer_174_dom_precip_type.gif&model=gfs&area=namer&storm=&cycle=06&param=dom_precip_type&fhr=174&group=Model+Guidance&imageSize=M&ps=model&use_mins=no&preselected_formatted_cycle_date=20150105+06+UTC&scrollx=0&scrolly=0

 

http://mag.ncep.noaa.gov/Image.php?image=data%2Fgfs%2F06%2Fgfs_namer_180_dom_precip_type.gif&model=gfs&area=namer&storm=&cycle=06&param=dom_precip_type&fhr=180&group=Model+Guidance&imageSize=M&ps=model&use_mins=no&preselected_formatted_cycle_date=20150105+06+UTC&scrollx=0&scrolly=0

 

http://mag.ncep.noaa.gov/Image.php?image=data%2Fgfs%2F06%2Fgfs_namer_186_dom_precip_type.gif&model=gfs&area=namer&storm=&cycle=06&param=dom_precip_type&fhr=186&group=Model+Guidance&imageSize=M&ps=model&use_mins=no&preselected_formatted_cycle_date=20150105+06+UTC&scrollx=0&scrolly=0

 

http://mag.ncep.noaa.gov/Image.php?image=data%2Fgfs%2F06%2Fgfs_namer_192_dom_precip_type.gif&model=gfs&area=namer&storm=&cycle=06&param=dom_precip_type&fhr=192&group=Model+Guidance&imageSize=M&ps=model&use_mins=no&preselected_formatted_cycle_date=20150105+06+UTC&scrollx=0&scrolly=0

 

No more frames to show..

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All great posts this morning.  I am going to set up a test with the arctic air masses to see and gauge how well the models handled them.  That is KEY number 1, the hell with the moisture, if we don't have the cold...forget it.  I think the EURO is WRONG when not having the 2nd high coming down.  Even the hr84 NAM has that 2nd high building back down and about to head into MT 

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Sunday-Monday has my interest. 6z GFS is an ice storm for parts of Carolinas for sure. At face value (which would almost certainly be too warm as modeled), GSO gets 0.45" of ZR and CLT gets 0.39"  CAE gets 0.19" of ZR by the way. 

 

This one will be a challenge, and I think all of the ranges of solutions you see on the modeling are on the table? Why? It's a very diffuse system at 500mb, so I would expect lots and lots of changes on the modeling this week. 

 

Just look at the 500mb vort off of 6z GFS, valid Sunday afternoon:

I agree, this HAS my attention and more than likely it just gives me some light rain.  You and I both know models will likely be wrong on the cold and how cold it actually is.

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All great posts this morning.  I am going to set up a test with the arctic air masses to see and gauge how well the models handled them.  That is KEY number 1, the hell with the moisture, if we don't have the cold...forget it.  I think the EURO is WRONG when not having the 2nd high coming down.  Even the hr84 NAM has that 2nd high building back down and about to head into MT 

 

I'm very interested to see how cold it gets and how much cold actually hangs around after this big arctic outbreak. Bring in a big high on it's heels and things could get interesting...that's why I have a feeling we may see more IP/SN p types on the onset as we move forward. You also don't see wedges that strong showing up on models which leads me to believe it will be much colder than models are handling it right now for SC/GA....I mean that's just a given anyways but models are making this very strong. 

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One thing thing that I'm trying to figure out is just when the onset of precipitation starts. Since this event as of now is starting out very strung out, this kind of reminds me of the lead up to the mid Feb storm last year. A least in Raleigh, I saw traces of snow as early as Monday when the main event was on Wednesday.

I think the models will adjust themselves in regards to timing as we get closer to the event. It's common on the GFS day 6-7 to string things out because it does not know which small piece of energy will serve as the main piece.

I would think by Wednesday or Thursday that debate will be settled

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I'm very interested to see how cold it gets and how much cold actually hangs around after this big arctic outbreak. Bring in a big high on it's heels and things could get interesting...that's why I have a feeling we may see more IP/SN p types on the onset as we move forward. You also don't see wedges that strong showing up on models which leads me to believe it will be much colder than models are handling it right now for SC/GA....I mean that's just a given anyways but models are making this very strong. 

 

Agreed, if the 6Z GFs is right then N. GA needs to watch out as well.  Reinforcing CAD's as opposed to in-situ events are usually modeled too weak for my area.  Not always but frequently.....

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I'm wish casting but with some weighted merit in hoping personally we could get another 10 to 14 day run of back to back to back etc events. Jan 2000 was as fun having events right on top of each other as it was because of the big one. These overrunning light events is the only way that can happen with big HP's one after the other parading through the ne.

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Indices looking better and better:

PNA - Should continue in the positive range through the LR

AO - Looks to definitely be going negative(averaged) in the LR

NAO - Looks to at least go to neutral in the LR

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/teleconnections.shtml

 

Interesting, the AO is essentially split, half solidly negative and half solidly positive.  The NAO is hopeless, the low over Greenland/Hudson Bay is never going away.  If we can get a nice +PNA and a -AO we may can start tracking real snow threats.   I know a few people have been saying we didn't have a -AO last winter but we did for all our events, the winter itself didn't average a -AO, but we spiked one at the right times.

post-2311-0-30956600-1420479541_thumb.pn

post-2311-0-86073600-1420479541_thumb.pn

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Interesting, the AO is essentially split, half solidly negative and half solidly positive.  The NAO is hopeless, the low over Greenland/Hudson Bay is never going away.  If we can get a nice +PNA and a -AO we may can start tracking real snow threats.   I know a few people have been saying we didn't have a -AO last winter but we did for all our events, the winter itself didn't average a -AO, but we spiked one at the right times.

Just the weenie come out of me but the negative runs are much more negative than the positive ones. I think really it's the trends of seeing more negative values showing up.

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Pack, we can totally work with a +PNA and a -AO. 

 

Agreed 100%, but nothing is a showing a -AO at this time.  Another 7-10 days of model watching for a -AO, if by that time the LR is not showing a -AO it will be SAI fail and good chance the AO will not help us this winter.

Day 12+ on both the EPS and GEFS show a revert back to a conus torch, west coast trough and east coast ridge.  If this is true you can kiss wintery weather goodbye until at least Feb.  It took the entire month of Dec to get out of that mess.   That's, if this comes true but the GEFS and EPS are in agreement.

post-2311-0-36526400-1420479817_thumb.pn

post-2311-0-18556900-1420479818_thumb.pn

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Yes we can work with that very reasonable. It is funny how some take 10 plus days as the gospel on the models. Will we warm a bit yes but there are some good trends.

 

Again, nothing is showing a -AO...It's funny how people simply ignore the models and season trends and just assume blind optimism will save the day.

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