Winter 2007-08: Preliminary Thoughts

[MetSul Weather Center]

Dear Friends

I am writing to you from a private weather center in Southern Brazil - South America. The winter this year in this area of the globe was incredible. Buenos Aires, the capital of Argentina, got snow for the first time since 1918. Snow was much more frequent and intense and fell in many locations where it is rare. Take a look at the graphics por Pudahuel (Chile's capital Santiago) and Puerto Mont for 2007. See the plunge to the level of the 19th century.



We strongly suspect this winter may surprise lot of folks in the US and not be as warm as have been anticipated. CFS and other models are predictiong a warm climatic winter (DJF), but to the guys that hope to live a cold winter here is another model.





If this climate models proves to be correct, of course, the winter will not be as warm as expected.

Our winter over here in Southern Brazil was similar to these years: 1964, 1988, 1996 and 2000. 1964 was a strong analogue to our reality here so it is interesting to see what happened in 65 in the US. The following graphics show daily temperature departures for NYC (above) and Chicago (below).



Looking exclusively to the climatology of the winter in the US that followed our analogues years over here in the southern hemisphere the majority of the winters presented above average temperature, but with isolated EXTREME cold events.

The idea of very cold weather in the second half of the astronomical season (December to March), as shown in the 65 graphic for Chicago and the model predictions above, looks reasonable to us. So the second half of January, February and March could be colder.

Let's wait and see. Nature has the final call.

Best wishes

[donsutherland1]

Interesting situation, MetSul Weather Center.

Certainly, the temperature anomalies seemed to fit quite well with situations where the ENSO Region 1+2 anomaly averaged -1.000 or below for the June-August timeframe.

Composite: ENSO Region 1+2 anomalies -1.000 or below (June-August average):


June-August Temperature Anomalies:


In terms of September, here's how things worked out when the ENSO Region 1+2 anomalies averaged -1.000 or lower during the September-November timeframe.

Composite:


2007:


And a look ahead using the same anomalies for the September-November period as a whole:


If things hold generally true relative to past ENSO 1+2 events similar to the present one, Brazil will likely see cooler readings relative to normal than had prevailed during September as the Spring progresses. Summer might start cool there. The lastest seasonal forecast from the ECMWF hints at a generally cooler than normal summer in Brazil. The CFS has a large part of Brazil somewhat cooler than normal for the upcoming summer. The ECPC, which called for a cool September (the opposite of what transpired there), has a mixed outlook, with some areas somwhat warmer than normal and others cooler than normal in Brazil.

Time will tell.

[VoodooCadillac]

Those are some awesome stats - I can't produce anything like that, but I note that the NCEP 8-14 day outlook shows below normal temperatures for the Eastern United States.

[JBG]

Those are some awesome stats - I can't produce anything like that, but I note that the NCEP 8-14 day outlook shows below normal temperatures for the Eastern United States.

Which by and large hasn't happened. We've been around normal for a few days, above normal other days.

[donsutherland1]

JBG,

In general, this winter will probably see actual periods of cold proving shorter and more modest than that which is progged by the computer guidance. There could be a few exceptions.

As for November, my thinking for November's anomalies remains as follows:

Northeast: Below normal to near normal
Mid-Atlantic: Below normal
Southeast: Below normal
Ohio Valley: Near normal
Northern Plains: Above normal to much above normal
Central Plains: Above normal
Southern Plains: Above normal
Pacific Northwest: Above normal
California/Southwest: Above normal

A composite based on 1953, 1954, 1998 has done quite well with respect to forecasting areas of cool and warm anomalies since August. For the most part, that composite also supports my thinking for November (though my thinking is cooler in the Northeast than the composite would indicate).

Composite for August:


August 2007:


Composite for September:


September 2007:


Composite for October:


October 2007:


Composite for November:


December will probably see a transition toward the predominant winter pattern where much of the USA winds up warmer than normal for the month as a whole.

[JBG]

JBG,

In general, this winter will probably see actual periods of cold proving shorter and more modest than that which is progged by the computer guidance. There could be a few exceptions.

*******

December will probably see a transition toward the predominant winter pattern where much of the USA winds up warmer than normal for the month as a whole.

I.e. classic La Nina, on balance mild, with a few sharp cold and snowy bursts, like 1999-2000, or 1970-71?

[andyidaho]

No Kocin-Uccellini snowstorms are likely.

Doesn't NAO have some role in this? Wasn't there a major "Kocin-Uccellini" storm around January 26, 2000 (not sure of exact date but I remember it being Tuesday-Wednesday after January 24 and before January 31, 2000)? And what about the New Years Day 1971 storm? Wasn't that under similar ENSO conditions?

Local Temperature/Precipitation Profile:
Recent temperature and precipitation patterns have been consistent with a profile that typically witnessed much below normal snowfall in the East, especially in the Northeast. Average snowfall for such seasons came to 10.5” in Baltimore, 23.5” in Boston, 13.0” in New York City, and 9.6” in Washington, DC (DCA). Such snowfall is reasonably consistent with moderate/strong La Niña-negative PDO winters.

Does "negative PDO" mean "cold-phase" PDO?

Negative PDO is cool phase PDO. I am certain the negative PDO is part of the reason why WPAC is less active.

Will the PDO remain negative all winter? If it does my area get pounded hard with snow and cold.

[JBG]

Will the PDO remain negative all winter? If it does my area get pounded hard with snow and cold.

Correct me if I'm wrong, but isn't PDO generally a 20-30 year cycle?

[andyidaho]

Will the PDO remain negative all winter? If it does my area get pounded hard with snow and cold.

Correct me if I'm wrong, but isn't PDO generally a 20-30 year cycle?

Yes.

[JBG]

Will the PDO remain negative all winter? If it does my area get pounded hard with snow and cold.

Correct me if I'm wrong, but isn't PDO generally a 20-30 year cycle?

Yes.

Wouldn't that mean that you have another 15-25 winters (at least) to go?

[Category 5]

Winter was from January 22-April 16 last year. We didn't get a snowfall over 3 inches.