Chicago WX Posted September 23, 2014 Share Posted September 23, 2014 Season snowfall totals and the DJFM mean NAO and AO/NAM states for 16 Midwest and Northeast cities. I used the DJFM NAO and AO/NAM states as defined by Dr. James Hurrell: https://climatedataguide.ucar.edu/climate-data/hurrell-north-atlantic-oscillation-nao-index-station-based https://climatedataguide.ucar.edu/climate-data/hurrell-wintertime-slp-based-northern-annular-mode-nam-index First up, the overall statistics sorted by DJFM NAO values. I used median season snowfall totals for each city (1899-00 to 2013-14), to see if a season was "above normal" (AN), "below normal" (BN), or "around normal" (NM). HI in the chart is highest season total in each category, LO is the lowest, and AVG would be the average snowfall. Thing to keep in mind in all of this, is that these are all statistically based values/results. What the actual hemispheric charts look like may vary from certain NAO and AO/NAM values...and thus differing outcomes in some seasons. So despite all of this...buyer beware. Still, I think it's kind of interesting to see it broke down statistically. Columbus and Des Moines do better overall, in -NAO DJFM regimes. Green Bay is pretty much a toss up...and then you have Detroit, which does better overall in +NAO seasons. Matter of fact, it looks they are the opposite of every Midwest city in most categories. Indianapolis and St. Louis have better seasons with a -NAO...but I was a little surprised how badly STL did in strong -NAO's (-3 or lower). Chicago and Minneapolis are a little more mixed. Boston, Buffalo, and Burlington all seem to like a -NAO. Washington DC does too, as long as it's -2 or lower where 75% of the seasons are above the longterm median. A weak +NAO also sees DCA do well. All four have better season snowfall totals, overall, in -NAO winters...PIT especially so. PWM isn't as "dependent"...but still does better in -NAO seasons, -1 or lower particularly. Individual season charts up next. Link to comment Share on other sites More sharing options...
Chicago WX Posted September 23, 2014 Author Share Posted September 23, 2014 Midwest DJFM NAO and season snowfall totals: part I Link to comment Share on other sites More sharing options...
Chicago WX Posted September 23, 2014 Author Share Posted September 23, 2014 Midwest DJFM NAO and season snowfall totals: part II Link to comment Share on other sites More sharing options...
Chicago WX Posted September 23, 2014 Author Share Posted September 23, 2014 Northeast DJFM NAO and season snowfall totals: part I Link to comment Share on other sites More sharing options...
Chicago WX Posted September 23, 2014 Author Share Posted September 23, 2014 Northeast DJFM NAO and season snowfall totals: part II Link to comment Share on other sites More sharing options...
Chicago WX Posted September 23, 2014 Author Share Posted September 23, 2014 Overall charts for DJFM NAM (or Arctic Oscillation) and season snowfall totals. CMH and DSM fare better in -AO/NAM states...DTW and GRB in +AO/NAM. IND and STL, again do better in negative seasons. MSP and ORD all over the place. Odd one is STL does poorly in strong negatives, but good in strong positives. Overall, not a strong signal for these four. Except in certain categories. DCA is pretty "normal" for anything +0.5 or less, but +1.0 or greater and it's over. NYC, PHL, and PIT better in an overall negative state...PWM has more variable success. Link to comment Share on other sites More sharing options...
Chicago WX Posted September 23, 2014 Author Share Posted September 23, 2014 Midwest DJFM AO/NAM and season snowfall totals: part I Link to comment Share on other sites More sharing options...
Chicago WX Posted September 23, 2014 Author Share Posted September 23, 2014 Midwest DJFM AO/NAM and season snowfall totals: part II Link to comment Share on other sites More sharing options...
Chicago WX Posted September 23, 2014 Author Share Posted September 23, 2014 Northeast DJFM AO/NAM and season snowfall totals: part I Link to comment Share on other sites More sharing options...
Chicago WX Posted September 23, 2014 Author Share Posted September 23, 2014 Northeast DJFM AO/NAM and season snowfall totals: part II Link to comment Share on other sites More sharing options...
Chicago WX Posted September 23, 2014 Author Share Posted September 23, 2014 And finally, individual seasons with both the DJFM NAM and NAO indices. In chronological order, from 1899-00 to 2013-14. Midwest DJFM NAM & NAO and season snowfall totals: part I Link to comment Share on other sites More sharing options...
Chicago WX Posted September 23, 2014 Author Share Posted September 23, 2014 Midwest DJFM NAM & NAO and season snowfall totals: part II Link to comment Share on other sites More sharing options...
Chicago WX Posted September 23, 2014 Author Share Posted September 23, 2014 Northeast DJFM NAM & NAO and season snowfall totals: part I Link to comment Share on other sites More sharing options...
Chicago WX Posted September 23, 2014 Author Share Posted September 23, 2014 Northeast DJFM NAM & NAO and season snowfall totals: part II Link to comment Share on other sites More sharing options...
Chicago WX Posted September 23, 2014 Author Share Posted September 23, 2014 Best example of making sure to look at the whole picture, despite numbers...2011-12 vs 2013-14. Both had similar DJFM NAM and NAO values, but obviously the season results were in stark contrast to each other. 2011-12 DJFM NH 500 mean 2013-14 DJFM NH 500 mean Link to comment Share on other sites More sharing options...
AlaskaETC Posted September 23, 2014 Share Posted September 23, 2014 This is FANTASTIC! Thank you! Link to comment Share on other sites More sharing options...
icebreaker5221 Posted September 23, 2014 Share Posted September 23, 2014 Thanks for compiling all of these statistics. Two comments: Since there's quite a bit of correlation between the NAO and the AO (which makes sense when you think of the 500 mb patterns associated with these teleconnections), it's not surprising that most of the cities that do best with a -NAO also do best with a -AO. If you have time, it would be great to see dual composites for 2 indices that are not as well correlated, such as NAO/PNA or AO/EPO. PNA: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.pna.monthly.b5001.current.ascii.table EPO: http://www.esrl.noaa.gov/psd/data/correlation/epo.data (this is actually the EP/NP, the inverse of which roughly translates to the EPO) Second comment, which I'm sure you're already aware of: some of those seasons with above average snowfall but DJFM +NAO/+AO, especially for the northeast / mid-Atlantic, were positive overall for most of those 4 months, but featured a single month or less of -NAO/AO which brought 3/4 of the seasonal snowfall (often with a single storm or two). A single storm in an otherwise crappy pattern can make or break a season, especially for cities that have low median snowfall. Link to comment Share on other sites More sharing options...
Ginx snewx Posted September 23, 2014 Share Posted September 23, 2014 Just fantastic, thanks Link to comment Share on other sites More sharing options...
michsnowfreak Posted September 25, 2014 Share Posted September 25, 2014 I cant thank you enough Tim...AWESOME! What a reference page this will be, as are most of your threads. Link to comment Share on other sites More sharing options...
DTWXRISK Posted September 27, 2014 Share Posted September 27, 2014 fabulous work Link to comment Share on other sites More sharing options...
Chicago WX Posted September 27, 2014 Author Share Posted September 27, 2014 Thanks for the kind words everyone. Not sure if any of this means much, but it's sorta interesting to look at. And for icebreaker, here's the season snowfall totals with the PNA indices (CPC defined). I didn't do a DJFM mean, but listed them by monthly values. How I grouped them, regardless of "true" overall strength, was if 3 months had a -PNA value then it was put into one chart...and so on and so forth. Last chart is one that had months with two of each. 1949-50 not listed due to missing December value. All in all, usual caveats apply. Midwest 1949-50 to 2013-14 median season snowfall: Columbus, OH (CMH): 27.2" Des Moines, IA (DSM): 32.8" Detroit, MI (DTW): 42.8" Green Bay, WI (GRB): 47.9" Indianapolis, IN (IND): 24.8" Minneapolis, MN (MSP): 50.7" Chicago, IL (ORD): 39.2" St. Louis, MO (STL): 18.2" Season snowfall key: Dark blue highlighted: top 10 highest season snowfall Blue highlighted: above median season snowfall White highlighted: near median season snowfall Red highlighted: below median season snowfall Dark red highlighted: top 10 lowest season snowfall MW -PNA Seasons MW +PNA Seasons MW +/- PNA Seasons Link to comment Share on other sites More sharing options...
Chicago WX Posted September 27, 2014 Author Share Posted September 27, 2014 Northeast 1949-50 to 2013-14 median season snowfall: Boston, MA (BOS): 42.5" Buffalo, NY (BUF): 93.7" Burlington, VT (BTV): 83.0" Washington, DC (DCA): 12.5" New York, NY (NYC): 22.9" Philadelphia, PA (PHL): 18.8" Pittsburgh, PA (PIT): 41.2" Portland, ME (PWM): 69.8" NE -PNA Seasons NE +PNA Seasons NE +/- PNA Seasons Link to comment Share on other sites More sharing options...
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