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Texas Snowman wrote:Larry Cosgrove: "...but yet another surge of colder values looks to reach Texas by the end of next week."
http://www.examiner.com/weather-in-hous ... 12-30-2011
orangeblood wrote:hriverajr wrote:wxman57 wrote:And, by the way, my post above was merely my observations of what was depicted by the European model, not necessarily my forecast of what was going to happen. However, one thing appears certain. There isn't much cold air currently in Canada and there isn't much snow cover across the U.S., which means we're not likely to see much cold air down south through at least the 2nd week of January.
Yep its only common sense, you don't even have to look at the models. You have to have the cold air really build up. Takes time at least 5-7 days. Then it has to be dislodged and move south another 3-7 days. So at a minimum that is over a week. Right now we don't even have any indications of that happening short term. i would say we are safe from significant cold air intrusions (Texas) at least through the 7th of January and most likely longer.
I'm going to have to respectfully disagree with you on this....cold air building in Canada isn't the only way we can get cold air intrusions down here. One way is from Alaska...there is plenty of cold air building in Alaska and the Bering Straight right now (25-30 below normal in some places) and if that Alaskan Vortex retrogrades to the west any, then look out in the lower 48 because some of that Alaskan cold has a chance to make it this way. All you need is help from the polar jet to break off a piece of that cold high pressure, bringing it quickly through Canada directly down the spine of the Rockies and into the southern plains (sometimes making it down here in less than 3 days). And sure enough that is exactly what the 18Z GFS is showing for next weekend.
There is plenty of cold air close enough to tap into and if the polar jet reconfigures itself just right then look out below. Now, it'll be hard to get sustained cold around here (we need the PV to entrain itself north of the Great Lakes for that) but it can get quite cold for a couple of days with a shot like the one I'm describing above. This is just something I've noticed looking back at past Upper Level and surface maps over the years.
The dark red shading would indicate a some crazy positive 500mb anomalies meaning any cold air up there should start marching to the US. 
hehe
wxman57 wrote:
Depends on what data you're looking at. Taking a look at the European forecasts, both the NAO and AO remain positive through the 13th. No prediction of either going negative. Stratospheric warming fades away by mid January (GFS). GFS operational does indicate temperatures across western Canada finally cooling down to well below normal by the 13th. But the GFS has been quite poor in its long-range predictions as well. GFS ensembles have the air 5-10F above normal in western Canada the 2nd week of January where the operational run has temps 20-30F below normal. In fact, none of the models has done really well in the long-term with the current pattern.
And, by the way, my post above was merely my observations of what was depicted by the European model, not necessarily my forecast of what was going to happen. However, one thing appears certain. There isn't much cold air currently in Canada and there isn't much snow cover across the U.S., which means we're not likely to see much cold air down south through at least the 2nd week of January.
iorange55 wrote:GFS still looks interesting for the middle of January! Got a good feeling things will "heat up" in a week or two.
Ntxw wrote:Portastorm wrote:The recent chatter online suggests that the polar vortex may be getting displaced from where it has set up its location. When the polar vortex breaks down, per se, it is usually accompanied by sudden stratospheric warming (SSW) which altogether can create a major turn to bitter cold for the continental US.
Here is a link to a decent article on the subject:
http://www.aer.com/science-research/climate-weather/climate-dynamics/polar-vortex-impact-winter-weather
To add, SSW is not the only mechanism that can displace the PV. Tropical forcing (MJO) can too as well. Many times we focus on SSW as a precursor to cold outbreaks but it can also come from other places as well not involving the stratosphere!
Lots of people out and about jogging/biking/leaf cleaning, etc. So not all bad. I want snow though. 
weatherdude1108 wrote:Ntxw wrote:Portastorm wrote:The recent chatter online suggests that the polar vortex may be getting displaced from where it has set up its location. When the polar vortex breaks down, per se, it is usually accompanied by sudden stratospheric warming (SSW) which altogether can create a major turn to bitter cold for the continental US.
Here is a link to a decent article on the subject:
http://www.aer.com/science-research/climate-weather/climate-dynamics/polar-vortex-impact-winter-weather
To add, SSW is not the only mechanism that can displace the PV. Tropical forcing (MJO) can too as well. Many times we focus on SSW as a precursor to cold outbreaks but it can also come from other places as well not involving the stratosphere!
Thank you all for the link and info.! It's more clear to me now. Temps 12 to 17 degrees above
normal. Yeah, back to the textbook "warm and dry" La Nina.
jogging/biking/leaf cleaning, etc. So not all bad.
To add to your post Turtle, the GFS has been consisting on building up some pretty cold air in NW Canada around Jan 10th onward. The GFS and its Ensembles also forecast the AO to turn Negative in around 10 days or so. Perhaps Texas could be looking at some winter fun after the 15th?? 
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