Yep!
The orange/red colors indicate blocking and the blue colors indicate a trough or lower pressures. On the map above you have blocking over Alaska and blocking over the North Atlantic near Greenland. This type of setup would indicate a -NAO/-EPO and would promote a huge dip south in the jet stream causing a big trough over the southern U.S. Normally, the jet stream just carries Pacific air into the U.S. We call that zonal flow because the flow is just flat west to east across the country, but since there’s a block near Alaska, the jet stream can’t go into a block so it has to go around it. So what the jet stream does is that it goes north of the block and goes into the Artic/Polar regions and taps into the Artic air. It can’t go east because of the huge block near Greenland so it goes south through the path of least resistance. We could call this cross polar flow because the flow of the jet stream is coming straight out of the Artic regions.
You can see what starts to happen in the pic above when you get the -EPO/-NAO combo. Our source region (western/northern Canada) gets flooded with cold air from the Artic and it’s headed south.
Now look what happens with this setup up in Canada. You have a 10141mb high getting ready to drop south into the U.S. and then a massive Artic high pressure of 1056mb that’s really building up the Artic air and driving it south. The stronger the high pressure builds is a good indicator of how cold the air will get. Any high pressure that’s 1040mb or more is a pretty strong high. Anything north of 1050mb is crazy high and strong. Now if you get a high that’s 1060mb or stronger then that’s when you can start talking about some historic cold.
Now the last piece that you need for snow in the south. Look at the low/trough in southern Cali. That indicates an incoming storm system. If we can get that trough to dig further south into Mexico and then cut across central or south Texas and pull down that Artic air we would all be very happy in Texas and most likely you would be too in Louisiana.
