November PDO: -0.63

[donsutherland1]

The PDO continued to fall in November, dropping to -0.63. It now appears increasingly likely that the winter will see the PDO average < 0. This could have implications, especially if the NAO does not average < 0. If the NAO averages < 0, past winters have generally had an opportunity to be snowy in both the Midwest and the East i.e., during seasons where the MEI ranged between +0.00 and +0.99 (very likely in 2004-05) and the NAO was negative, snowfall averaged:

Chicago: 51.4"
Philadelphia: 32.3"

However, in such winters, Buffalo received below normal snowfall (82.4"). The very slow start with regard to snowfall in Buffalo may well be pointing to just such an outcome.

I might have something more detailed later tonight.

[WEATHERGURU]

Hey Don, with all this new data coming in what is your thoughts on snowfall for Detroit, Mi? I suspect it will be a good season.. Thanks for your excellent post of information..

[donsutherland1]

WEATHERGURU,

I'm still expecting that Detroit will see 40"-50" of snow this winter.

[donsutherland1]

The November PDO Index came in at –0.63. It now appears increasingly likely that Winter 2004-05 could be the first winter since the dreadful Winter 2001-02 to see the PDO average < 0 during the December-March period.

Since 1950-51 when regular monthly recordkeeping for the PDO began, there have been six seasons in which the PDO dropped below zero beginning in October and then continued to drop farther during November: 1963, 1965, 1968, 1971, 1989, 1990. All six seasons saw the December-March PDO average < 0:

1963-64: -0.54
1965-66: -0.52
1968-69: -1.00
1971-72: -1.95
1989-90: -0.45
1990-91: -1.55

Assuming that Winter 2004-05 will have a negative PDO (which is different from my mid-October assumption), a number of scenarios can help shed some light on what might lie ahead for select cities.

First, for perspective, the following are the 1950-51 through 2003-04 average seasonal snowfall totals for select cites:

Boston: 42.6”
Buffalo: 95.9”
Burlington: 81.0”
Chicago: 41.4”
New York City: 24.4”
Philadelphia: 21.5”
Pittsburgh: 43.6”
St. Louis: 19.6”
Washington, DC: 16.6”

In all seasons when the PDO < 0 during the December-March period, the average seasonal snowfall figures for those cities came to:

Boston: 36.9”
Buffalo: 85.9”
Burlington: 77.8”
Chicago: 42.0”
New York City: 19.7”
Philadelphia: 18.4”
Pittsburgh: 39.4”
St. Louis: 16.8”
Washington, DC: 14.8”

It should be noted that the increasing likelihood of a negative PDO also suggests that the season will see the PNA average < 0 during the December-March period (another change from what I had earlier anticipated). In 23/29 (79%) of seasons when the PDO < 0, the PNA also averaged < 0.

The following are average seasonal snowfall figures for select scenarios when the PDO averages < 0:

PNA Averages < 0:

Boston: 38.1”
Buffalo: 87.2”
Burlington: 79.7”
Chicago: 44.1”
New York City: 20.9”
Philadelphia: 19.2”
Pittsburgh: 40.0”
St. Louis: 17.0”
Washington, DC: 14.8”

PNA Averages > 0:

Boston: 32.7”
Buffalo: 81.0”
Burlington: 70.5”
Chicago: 33.9”
New York City: 14.8”
Philadelphia: 15.4”
Pittsburgh: 37.0”
St. Louis: 14.2”
Washington, DC: 14.7”

QBO Average Ranges from –6.00 to +6.00 during December-March:

Boston: 32.9”
Buffalo: 85.3”
Burlington: 70.1”
Chicago: 43.4”
New York City: 18.1”
Philadelphia: 18.3”
Pittsburgh: 36.1”
St. Louis: 19.3”
Washington, DC: 14.0”

MEI Average Ranges from +0.00 to +0.99 during December-March:

Boston: 37.0”
Buffalo: 78.4”
Burlington: 72.5”
Chicago: 44.7”
New York City: 24.2”
Philadelphia: 23.0”
Pittsburgh: 34.5”
St. Louis: 17.8”
Washington, DC: 17.5”

NAO Averages < 0:

Boston: 43.1”
Buffalo: 87.2”
Burlington: 83.4”
Chicago: 44.0”
New York City: 22.2”
Philadelphia: 22.1”
Pittsburgh: 48.9”
St. Louis: 18.8”
Washington, DC: 18.2”

NAO Averages > 0:

Boston: 32.0”
Buffalo: 84.9”
Burlington: 73.2”
Chicago: 40.3”
New York City: 17.6”
Philadelphia: 15.4”
Pittsburgh: 31.7”
St. Louis: 15.1”
Washington, DC: 12.1”

Finally, the following are three combinations that are more likely than not to predominate during the 2004-05 season:

MEI Averages +0.00 to +0.99, ENSO Region 1+2 Averages < 25°C, and ENSO Region 3.4 Averages 27°C or Above:

Boston: 41.1”
Buffalo: 64.5”
Burlington: 49.5”
Chicago: 36.0”
New York City: 34.8”
Philadelphia: 23.8”
Pittsburgh: 39.9”
St. Louis: 24.2”
Washington, DC: 20.9”

QBO Average from –6.00 to +6.00 and MEI Averages +0.00 to +0.99:

Boston: 36.0”
Buffalo: 78.7”
Burlington: 70.4”
Chicago: 47.9”
New York City: 26.3”
Philadelphia: 28.1”
Pittsburgh: 38.6”
St. Louis: 17.6”
Washington, DC: 24.4”

NAO Averages < 0 and MEI Averages +0.00 to +0.99:

Boston: 48.1”
Buffalo: 82.4”
Burlington: 79.0”
Chicago: 51.4”
New York City: 34.8”
Philadelphia: 32.3”
Pittsburgh: 42.6”
St. Louis: 23.4”
Washington, DC: 26.8”

Finally, for those who are interested, the snowiest negative PDO season for each of the select cities was:

Boston: 1963-64: 63.0”
Buffalo: 2001-02: 132.4”
Burlington: 1970-71: 145.4”
Chicago: 1978-79: 89.7”
New York City: 1966-67: 51.5”
Philadelphia: 1966-67: 44.3”
Pittsburgh: 1950-51: 82.0”
St. Louis: 1973-74: 42.4”
Washington, DC: 1978-79: 37.7”

[wxguy25]

Excellent as always, Don. I agree completely.

I’m looking hard at the 1968-69 winter since the PDO has now reversed, the N PAC signal was for a brief time during the OCT-NOV period similar WRT to the location/configuration of the SSTA pools, and the QBO has begun to decline steadlier. That’s not to say it won’t rebound, as I have a feeling the longer westerly cycle is due in part to the El Nino event’s effect on Rossby wave activity.

A similar situation could occur later on, so I’m not entirely confident that we’ve seen the last of these jumps in the QBO numbers. Thusly I would be inclined to hypothesize that 1963-64 stands as the best QBO analog.

Lets assume for inquiry sake that the QBO continues to decline and turns west either in FEB or MAR. the 1968-69 QBO values would then be similar; we must also consider what happens if the warm pool gets eradicated again like it was in the late summer and early fall, as it would once again imply 1968-69 becoming a dominant analog for the second half of the winter (its always a possibility although I seriously doubt it will happen).

As far as the PDO is concerned, were all aware that the cold phase of the PDO favors a +EP pattern (or EPO depending on how you want to term it) and a variable PAC jet, but one that at times can overwhelm the pattern. In the abovementioned years, the Aleutian low was anomalously weak for an El Nino year where the subtropical ridge in the northern hemisphere is extended eastwardly. Part of the equation could have been due to solar influences w/ geomagnetic activity killing the Aleutian low in 1968-69, and perhaps to a degree the East QBO, but nevertheless the N PAC signal plays the largest role.

BTW, have you seen the New CFS and GSM? If so what are your thoughts?

My take is that the data the model is initializing (which of course is based on the current pattern) is causing the models to overemphasize the amount of warming. After all there is NOT going to be a huge positive anomaly in west/central Canada developed downstream of a killer PAC low. Heck we can barely get one now so as it is—and the SSTA configuration and PDO index DON’T support this happening. IMO both runs should be tossed in the crapper.

We should begin to see the ridge develop along or just off the west coast w/ lots of rex blocking in that region over the next few weeks now that the SSTA warm pool is gaining longitude--being centered between 145-150W / 30-50N. But still the ridge has to get out of Europe in order to get the Caspian connection to develop. For the past few weeks it’s been all zonal over that part of Asia.

w/o the PV in Canada it’s going to be hard to get any HISTORIC or MAJOR cold, but a colder pattern relative to what we have been seeing? Absolutely.

[yoda]

Excellent posts Don and Wxguy25. Very informative.

[donsutherland1]

Thanks, Wxguy25.

I agree that 1963-64 looks best in terms of the QBO at this point in time. I am also wary of another temporary rebound in the QBO (in most cases in which it had one rebound, it also wound up having a second one before going East).

Finally, based on analogs and what I have seen in terms of SSTAs, I don't like the extent of warming shown on the CFS. In fact, in the past when the PDO averaged < 0, the MEI came out between +0.00 and +0.99, and the Region 3.4 anomaly amount to +0.25° or above, the Pacific Northwest saw temperatures average below normal. In addition, in the 17 seasons where the PDO averaged < -0.50, 13 saw the Pacific Northwest wind up normal or cooler than normal. Overall, I am very skeptical of the model run, especially that of the CFS.