Hey Baby it do what it do

The great philosopher and musician Ray Charles was once asked in interview how his music appealed to so many different groups of people... ethnically economically racially... and he said "Hey baby it do what it do..."

Which is really when I think about it sort of a variant on the philosophical underpinnings of Aristotle Marcus Aurelius and Dr. Hannibal Lecter. Of each thing we muts what does it do? what is its nature? What is its significance?... How does this exactly relate to the current pattern we have have over North Ameica? Well it's kind of entertaining watching the various forecasting services and a few individual forecasters continually try to assert that the new cold pattern is not really going to be all that cold... which is what they were saying last week or that it isnt going to last all that long.... then in the very next sentence forecast the cold pattern is now going to last into Midle of February ...but THEN it breaks down...

"Hey baby it do what it do..."

I think it's a little harsh to assert that such a warm biased forecast for second half of FEB and March is delusional but for life for me I cannot understand what the REASONING is behind that sort of call. The El Niño continues to weaken at a dramatic pace and surely even the most hard-nosed stubborn warm biased forecasters have to see the significant difference between the pattern of November and early December and the current pattern and what we will likly see in early FEB. Just like the data is strongly correlates that when you have moderate / strong El Nino you have a mild winter pattern in North America... it is equally strong that when you have weak El Niño conditions you end up with a colder to much colder than Normal over the central and eastern CONUS.

We'll start by taking a look at the operational GFS at 1am WED... as you can see there a pretty strong shortwave which is crashing underneath the Big west coast Ridge. This is a process known as undercutting and allows the Ridge over the West coast of Canada to become a OMEGA RIDGE or a REX BLOCK.
http://weather.unisys.com/gfsx/7d/gfsx_500_7d.html

Note the 2 S/Ws... one coming into N Calif and Oregon and the other dropping south from western Canada about to enter eastern MT.

This process is called undercutting and IF it does in fact occur then we are going to significantly increase the chances for much of the central and eastern US seeing a snowy pattern as a month comes to an end and we move into February. But first the Undecutting has to occur. Seeing it a model is NOT the same thing as reality.

It do what it do ...

The undercutting process will SPLIT the flow which would significant increase the activity in the STJ/ southern branch which of course leads to increased chance of seeing systems develop either in the lower Plains and Deep South and NOT the Gulf Coast.

You see the main problem have right now is that all the shortwave activity coming out of STJ / southern branch is over northern portions of Mexico and S Texas. In the current flow... and in the pattern over the next 7 days... these S/Ws cannot Gain enough Latitude so any surface development is over the Northern Gulf and the Lows end up sliding off the SC and GA in ENE direction.

However if we do enter the process undercutting the Ridge in the last few days in January and early FEB this will (as I said) establish a Split flow pattern. And more importantly the S/ws coming in across the Southwest will have enough time and distance to gain latitude as they head E or ENE . In other words IF you have a shortwave over the SE Texas that tracks in a 060 direction (ENE) it's going to slide out to sea as will the surface Low. The same track however with a shortwave which is starting back over the Southwest... well now you are in a different ball game.

By day 8 on the 0z op GFS ... the two s/w... are GONE because the op GFS past day 8 suffers from Model resolution truncation ... which is a fancy way of saying the model past day 8 blows Chunks .
http://weather.unisys.com/gfsx/8d/gfsx_500_8d.html

The 0z day 9 and day 10 ECMWF with its vastly superior model resolution has NOT lost these two S/Ws and this results in a pretty good over running pattern by Day 10.
http://wxrisk.com/MODELFOLDERS/today/jan24/1920zEU5h.gif
http://wxrisk.com/MODELFOLDERS/today/jan24/10D0zEU5h.gif

The midday WED 12z GFS has caught on to this trend and is now showing these two S/Ws in a much better depiction. The shortwave which undercuts the Ridge near Oregon / N California is much stronger at D6 but of course the model resolution is still pretty good. At 192 hrs... when the model resolution is truncated we can see that the midday operational GFS has two fairly strong shortwaves but the southern S/W appears to be getting stuck over the southern Calif/Vegas area. Not surprisingly given the bias of the operational GFS the model put all its emphasis on the shortwave that stopping into the coat is at 192 hrs ... and it is this feature which develops a system for D9.
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/12/images/gfs_slp_216s.gif


The midday ECMWF at day 7 again is showing significant activity over the western CONUS with two very distinct and powerful S/Ws. The Midday at day 9 does show some sort of triple point surface Low that brings a pretty decent amount of snow to the Tennessee Valley & Middle Atlantic states... followed by a bitter Arctic out break at D10
http://wxrisk.com/MODELFOLDERS/today/jan24/7D12zEU5h.gif
http://wxrisk.com/MODELFOLDERS/today/jan24/9D12zEU5h.gif
http://wxrisk.com/MODELFOLDERS/today/jan24/10d12zEU5h.gif

this idea is supported by the 12z Op GFS as well .
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/12/images/gfs_500_240s.gif
http://www.meteo.psu.edu/~gadomski/ENSHGT_12z/f240.html

One last note... the 0z op GFS at 312 hrs was trying once again to knock down the Ridge over old western North America trough and develop a flat Ridge over the Southeast which of course end the cold pattern east of the Mississippi River.

But we can see from this link most of the ensembles 0z data does not support that idea at all
http://wxrisk.com/MODELFOLDERS/today/jan24/0z5hf312.gif

nor does the 312 hr 12z ensembles mean. As we can see the white lines are showing the operational run and the trough trying to reform at West while the fMost of the members show the trough staying strongly over the eastern North America
http://wxrisk.com/MODELFOLDERS/today/jan24/f312.gif

hey Baby it do what it do