calumet paramaribo: Will he or won't he? Weak El Ni?o's impact on our Winter unclear ...

Saturday, October 6, 2012

Will he or won't he? Weak El Ni?o's impact on our Winter unclear ...

Posted on: 8:34 am, October 5, 2012, by Carrie Rose, updated on: 09:47am, October 5, 2012

RICHMOND, Va. (WTVR) ? We may remain on ?El Ni?o Watch? according to the Climate Prediction Center (CPC), but with such puny signals from the Equatorial Pacific late Summer into the beginning of Fall, we can?t count on El Ni?o to be a dominant guide for a Winter outlook. The CPC issued this update, ?Due to the recent slowdown in the development of El Nino, it is not clear whether a fully coupled El Ni?o will emerge. The majority of models indicate that borderline ENSO-neutral/ weak El Ni?o conditions will continue, and about half suggest that El Ni?o could develop, but remain weak.?

What is El Ni?o, and why does it matter anyway?
El Ni?o is the warming of the Equatorial Pacific surface and near-surface waters off of the northwest coast of South America. When you warm that much water, it will impact wind patterns globally. Here?s what a strong El Ni?o looks like on sea surface temperatures:

Climate Prediction Center: Sea Surface Temperatures (?C).

And this is what the warm departure looks like:

Climate Prediction Center: During a strong El Ni?o ocean temperatures can average 2?C ? 3.5?C (4?F ? 6?F) above normal between the date line and the west coast of South America.

Here are the typical El Ni?o weather impacts during the Northern Hemisphere Winter/Southern Hemisphere Summer because of El Ni?o-driven wind pattern changes:

Climate Prediction Center

There is substantial evidence that when El Ni?o occurs in the North American Winter, it brings cooler and wetter-than-average winters to the Southeast U.S., including into Southeast Virginia. Obviously, that is of significant interest to us in Virginia!

Here?s what the transition from La Ni?a to weak El Ni?o has looked like since Fall 2011 until now.

Climate Prediction Center

And here?s a closer look at the sea surface temperatures and anomalies now.

Climate Prediction Center

The anomalies are barely showing a warm departure in the eastern Equatorial Pacific. Hence, why the CPC has to call this a near-ENSO neutral/weak El Ni?o. There?s just not enough evidence to indicate that El Ni?o will continue or strengthen into the coming weeks and months. That means long-range forecasters trying to predict what kind of Winter we?ll have in different parts of the U.S. can?t rely on the usually helpful guide provided by an El Ni?o or La Ni?a Winter. In fact, even the climate computers are saying, ?Eh, maybe, maybe not.?

The International Research Institute for Climate and Society

So what does that mean for me as a meteorologist trying to look ahead for you? I?ll have to focus more on patterns that set up over shorter time-frames, on the scale of days to a week or so, as opposed to months. In other words, I plan to approach my Winter forecast as if all bets are off and anything can happen. I can?t say we?ll have a dud of a Winter without storms and deep cold. Neither can I say we?ll have an epic ?snowmageddon? repeat. It?s just unclear, based on this Call-Me-Maybe-El Ni?o. (Oh dear, now I have that song in my head?)

One long-range outlook has already been released based on the prevailing pattern this year (i.e., hot and dry in the central and southwest U.S.).? The current seasonal drought outlook shows persistence of the drought in the drought-stricken central and western U.S., with improvement in Virginia.

Our Abnormally Dry area in the Commonwealth is down to 43 percent of the state compared to three months ago when 91 percent of the state was at least Abnormally Dry. However, the Moderate Drought (D1) is worse now than three months ago in central and northeast Virginia, but did show a slight improvement over the past week.