La Nina's and historical sample sizes

[ace0927]

here is my major issue with analog forecasting and especially comparing past La Nina's and El Nino's....this also carries over to the global warming debate (which i admittedly know nothing w/re to the specifics)....the world has been around for millions of years (5771 according to the jewish calendar) so using the 10 mod/strong La Nina's over the past 75 years as a sample is just flat out foolish. the sample size is too small to make the assumption that we make about the true possibilities.

I dont claim to know science at all...I am however a logical thinker.

Has there ever been a la Nina with such a strong -NAO? if not, then all the past mod/strong La Nina's would not be good comparisons and if there is one or two other seasons like this maybe there are other factors that might not be taken into account that are altering sensible weather.

Historically- correct me if I am wrong- we do best, in terms of snow, during the weak El Nino winters, yet our best winter (95-96) came during a weak Nina with a strong -nao...go figure.

My point, dont take too much for granted, dont assume because its a strong La Nina that past events will be indicative of future events....it never works that way.

if you look at the Kocin book you will obviously notice that not one storms upper/surface features are anywhere near the same, in terms of specifics not general features, like snowflakes.

I am hoping to start a discussion for other peoples opinions on this topic...

[A-L-E-X]

You have to go further back in time to find snowy moderate or strong la ninas, Ace. The analogs that were mentioned were 1909-10, 1916-17, 1917-18 and 1955-56. Quite different from the early 70s or late 90s mod-strong la ninas as you will notice lol.

Weak la ninas are our second snowiest ENSO (as per Tony's data), after weak el nino. Weak la ninas that come after el ninos are especially likely to be snowy (1966-67 and 1995-96). A couple other relatively recent snowy la ninas were 2000-01 and 2005-06 (which came after the el nino winter of 2004-05.)

Note: A common characteristic of the recent snowy la ninas (even the ones with a cold and snowy December) is a mild January. Cold usually comes back after they weaken further later on in the season. Good examples of this are 1966-67, 1995-96, 2005-06. Note that all the summers preceding those winters were scorchers for us-- just like last summer was.

I agree with you about small sample sizes and most people use post 1950 data-- which limits it even further. The winters I mentioned in my first paragraph were cold and snowy; 1916-17 and 1917-18 being NYC's only back to back 50 inch plus snowfall winters and the latter winter was renowned for the extremity of its cold and prelonged below zero lows (including a -13 in December!) As you will note, winters during WW1 (and WW2) were also extremely cold and snowy in Europe.