2010-2011 Winter weather outlook for Tennessee.

[InMemphis]

So we could see an active October in terms of severe weather?

[StormNine]

So we could see an active October in terms of severe weather?

Anywhere from October 2010 to April 2011 I would watch out for several wild severe weather events.  It is unknown how exactly the La Nina will act, but it will be a very strong one.  Using climatically that typically favors an active late fall/winter/early spring severe weather season. 

[tennessee storm09]

yeah look for  some big time severe weather events. if that pacific jet gets strong like i think it will, that will aid fuel for the fire. could be some wild times ahead were the battle zone converges

[Curt]

If one looks to 73-74 as an analog it was a roller coaster temp wise DJF. There were several days below freezing at a time with a few nuicance snow events and a major ice storm in Memphis.  However, no 2 winters are exactly alike.

[tennessee storm09]

yeah i was 12 years old duriing the ice storm of 74. it was big and seems like it snowed a couple of inches on top of it. that could be a good comparioson, we  had a little of everything from severe to ice and snow.

[Curt]

Interesting link I found from EWx dating La Nina's back to 1868.

ftp://www.coaps.fsu.edu/pub/JMA_SST_Index/jmasst1868-today.filter-5

Top Ten Strongest LaNina's at the beginning of winter/ Snowfall during the Season at KMEM:

 1916-17   13.8 in
 1892-93   12.1 in
 1942-43   Trace
 1973-74   1.4 in
 1970-71   9.3in
 1975-76   0.4in
 1909-10   18.2in
 1949-50   Trace
 1955-56   5.3in
 1988-89   0.3in
 1999-00   3.0in

Obvioulsy snowfall is not just LaNina dependent. 6 of those winters would be considered below normal snowfall (although 73-74 had a major ice storm). 4 are above normal, in some cases much above normal. One winter, 55-56, is considered normal. Other factors come into play that would influence a winter season dramatically in some cases.

Winter of 1909-10 espcially interesting at Covington, TN, the only station in the Memphis area that is dated back that far. It featured nearly 26 inches of snow at that station, well over a foot more than Memphis. Nearly every snowfall of the winter occured after temps in the 60's, with temps falling to single digits to zero after the snow. Would be interesting to see flucuations in NAO/AO during this time with such wild temp swings.

[StormNine]

 in 2007-08 there were several close calls in the Mid-South esp. Western KY and NW TN.  We finished near average in snow anyway, so we could of been quite above average if some of those events didn't go bust.

 That is the main difference between a winter like 07-08 and 1909-10 is that the events went bust in 2007-08, that did not go bust in 1909-10.  Also beware the models will not handle those temp. swings, and strong Pacific jet well at all this winter.  A lot of pain and frustration will be caused if you take model runs after 60 to 72 hours seriously.

[Curt]

Interesting article about the PDO which appears to be entering a negative phase starting in 2008. Its different than ENSO in that it averages either warm or cool phase based on 20-30 yr increments. The 80s-mid 2000's were in a warm phase, with a possible shift to cool now. That in combo with ENSo, a mod-strong La Nina could increase the volatility of temp swings in our area this winter.

http://www.atmos.washington.edu/~mantua/REPORTS/PDO/PDO_egec.htm

[Curt]

Interesting article about the possible cooling phase of AMO (Atlantic Mutidecadal Oscillation). It appears it alsotakes several years to fully cool and we may be enterting the front end of that phase. Also, the article says that moderate to strong ENSO events may modify or override the AMO. With the strong La nina here, should be an interesting combo with the AMO/PDO being in a negative or cool event. ENSO aside, the author suggests that we may be headed for the colder winters of the 60s and 70s in the next 2-3 decades.

http://wattsupwithth...quite-cool-yet/

[StormNine]

Interesting article about the possible cooling phase of AMO (Atlantic Mutidecadal Oscillation). It appears it alsotakes several years to fully cool and we may be enterting the front end of that phase. Also, the article says that moderate to strong ENSO events may modify or override the AMO. With the strong La nina here, should be an interesting combo with the AMO/PDO being in a negative or cool event. ENSO aside, the author suggests that we may be headed for the colder winters of the 60s and 70s in the next 2-3 decades.

http://wattsupwithth...quite-cool-yet/

That calls for a thumbs up.

[StormNine]

First is the Temp. Map and Second is the Precip map. This is a very preliminary look, of my thoughts of winter. Factors include a potent La Nina event, a -PDO pattern, an active Pacific jet, potential for a battleground zone. Due to uncertainties with NAO (on this outlook I did a neutral to slightly positive one, but that would be overtaken by the unfavorable Pacific and ENSO.

- A SE Ridge is a big story this winter, this could create above average to very above average temps. at the time across the Eastern and Southeastern USA.
- The active Northern Stream and where it collides with the SE Ridge "Battleground zone" are also huge stories. The "Battleground Zone" could face well above average precipitation, severe weather events, and even a few overrunning winter events cannot be ruled out.
- Although small there is a small Below Average Temp zone on the edge of the map. At this point I will go for Below Average temps. from NE Colorado and Nebraska Panhandle and extended towards the Northern Rockies and Pacific NW, and also portions of Western Canada and portions of the Arctic, this is where I think the only widespread Below Average Temps will be.
- There could be a period for a good snow in Late Feb./March.
- Cool Season severe weather threats will be a problem for much of the Southeast and MS/OH valley areas. I think the best chances will be in the Mid-South where the battleground will be maximized, but all of the SE needs to be on ground for severe wx potential.
- If a Wedge forms that could make temps. a little closer to average for portions of the SE instead of way above average, also if the battleground pushed more southward then, temps may be closer to average in Northern and Western portions of the SE then depicted on the map.
- Some analogs are stronger La Nina's of the 50's and 70's. Such as 49-50, 55-56, 73-74, and even 07-08. Although similar patterns to these winters are likely, just because you got hit by two tornadoes in 07-08, or you house flooded in 49-50 doesn't mean that same specific weather event will happen again, this are the large pattern analogs, not meant to predict, whether a tornado will hit your house, or anything like that.

[snowdog]

The link ctbp didnt work for me...here it is in case it doesnt work for others.  Interesting stuff. 

http://wattsupwiththat.com/2009/07/14/the-atlantic-multidecadal-oscillation-not-quite-cool-yet/

[Crockett]

My early thoughts:

It's a given that we're going to have a strong La Nina this winter. That makes it pretty much a given that our temperatures are going to average above normal.

But an above-normal average doesn't mean a constant blowtorch from December-February. I'm seeing some stuff on other forums where normally rational people are losing their heads over this La Nina. I think above average temps/below average snowfall is a very safe bet, but I'd be willing to bet two other things as well: 1.) We'll see cold snaps with some snow, and 2.) The severe weather threat won't be as great as some people think. That isn't to say that our cold snaps are going to be prolonged and it isn't to say that we aren't going to see some severe threats along the way. I think we're going to see a mixed bag with some pretty wild temperature and precipitation swings this winter. December could have normal to slightly below normal temps, January quite warm overall and February perhaps slightly above normal, IMO. The bottom line is that we just don't know how warm this winter is going to be until we see how the various teleconnectors line up. We may wind up with +5 temperature anomalies Dec-Feb, but I wouldn't bet the farm on it.

[tennessee storm09]

i agree with almost everything you say crockett except the severe will be a concern, no doubt. especially here in western tn. the battle zone will determine alot of that also. i have seen to many stron la nina winters, and they usually lead to a severe threat along the line.

[Crockett]

i agree with almost everything you say crockett except the severe will be a concern, no doubt. especially here in western tn. the battle zone will determine alot of that also. i have seen to many stron la nina winters, and they usually lead to a severe threat along the line.

I don't disagree that we're going to see some days this fall/winter that are going to have potential for severe weather. We're probably going to be in the warm sector of most storm systems this winter and that alone will create some severe potential even without the added factors. I just think some of the expectations I've read (elsewhere; not here) are unrealistic.