Sunday, November 10, 2013

2013-2014 Winter Update: Early November, 2013

This update on the 2013-2014 winter will address what has changed and what has not since the Final 2013-2014 Winter Forecast, as well as what the changes say about the upcoming winter.

What Has Changed
Prognosis on the Arctic Oscillation
The Arctic Oscillation is now anticipated to be rather positive this winter, as October SAI data, when accounted for the full 31 days of the month, shows a rather flat change from October 1 to November 1 over the SAI index area. This tells us that the Arctic Oscillation may not be as negative as previously thought. Also hurting the prospects of a negative Arctic Oscillation is the predicted positive AO for much of November. It is shown that the November Arctic Oscillation value can translate on a positive correlation for the following winter 68% of the time. For example, a negative Arctic Oscillation in November translates to a negative Arctic Oscillation in the following winter 68% of the time. The same goes for a positive AO. This is not good news for those wanting a negative Arctic Oscillation this winter, as the positive phase of the Arctic Oscillation tends to dampen prospects for cold weather. At this time, indications are that the AO may tend to be more positive than negative.

The October sunspot data was released in the last week, and it shows a worrying scenario for the upcoming winter. If we go by the acknowledgement that sunspot spikes precede a warm weather trend by 2-3 months, it's possible we see a solidly warm start to winter, possibly extending beyond December. This is currently to be determined as far as how the sunspots really impact the winter, but I personally don't like this new development as a winter weather fan.

What Hasn't Changed
Plains Outlook for a Snowy Winter
The Lezak Recurring Cycle continues to point to the Plains and Upper Midwest as being in line for a snowy winter this season. Multiple storm systems that have traversed through the region since October 1 indicate that the region of interest ought to have the advantage in the snow department this winter.

The Ocean Teleconnections
The Pacific Decadal Oscillation, Atlantic Multidecadal Oscillation, and ENSO indexes remain on track as forecasted: negative, positive and neutral, respectively.

The Quasi-Biennial Oscillation
Everything still on track for entry to Phase 7 by mid winter. Entry into that phase may be a tad earlier now, but the end half of winter should still see a full-blown Phase 7 QBO.

Practically everything else
The Final 2013-2014 Winter Forecast is looking fairly good at this point.

The warm start to winter still looks on, with a gradually cooler trend going on into winter. Expect a turbulent atmosphere/stratosphere in the end half of winter, as the changing QBO permits stratospheric warming events, and thus helps the chances for a negative Arctic Oscillation. Snow should favor the Plains this winter, with cold weather centered across the Plains, Midwest and Great Lakes. More to come as we press on into winter.



Cameron Jourdan Fry said...

Keeps getting worse and worse for us in Tennessee :( Tired of the plains hogging all the snow! Deep down, they know they want to share with the snow-deprived ;) Booo, SAI.

Anonymous said...

Even though with all these changes, do you still think the Great Lakes will still get a lot of snow this year? (I am tired of Chicago having winter duds)

Anonymous said...

Does this mean that southeast michigan will end up having a warm winter? I feel like i should go south to see snow. Wuts up with that?

Mark said...

I am a bit confused. You say AO is likely to be positive now, but you are leaving the winter forecast unchanged? Is the eastern US still progged to have below normal temps? Not sure how this new development can't affect the forecast at all. Are we still looking at overall below normal temps in PA? Thanks for maintaining a really great free site.

Anonymous said...

Disagree with the "very warm' December. But I suppose we'll see.

Andrew said...

Anonymous at 6:51: The Plains appear to be in line for the big snows, but I believe the Midwest and Great Lakes will see their fair share of snow.

Anonymous in SE michigan: Probably a cooler than normal winter- the sunspots and AO are two of well over a dozen pieces to the puzzle we call the winter forecast. No need for concern for now.

Mark: It's more of the Northern US that is in line for the coldest weather, and while the AO may stay positive overall this winter, I still believe cold weather will come to the Plains, Midwest, Great Lakes, etc. PA temps should stay relatively close to average or slightly below normal.

Anonymous at 7:38: "Very warm" in comparison to January and February. Interchangeable with "warm".

Anonymous said...

I believe that the projected Index may not be taking into account volcanic aerosol emissions. Volcanic activity has been high, especially in High Latitudes in mid-October, and it can be shown a correlation between near-equator volcanic activity and lower temperatures as well (i.e. Sinabung at the conclusion of October and beginning of November). The AO is projected to trend negative by several models and the European Ensembles project negative temp anomalies for much of the nation over the next few weeks. Volcanic aerosol emissions can lead to blocking regimes and quickly, especially if they are in high latitudes. I think the story of this winter is not going to be told simply by indices.

TQ said...

Can you link to the analysis showing "...the November Arctic Oscillation value can translate on a positive correlation for the following winter 68% of the time."