Tuesday, September 10, 2013

Pacific Sea Surface Temperatures Warming; Is an El Nino Winter Ahead?

Sea surface temperature anomalies across all four ENSO regions in the Pacific are warming in what could be a sign of the La Nina-like SST's we saw earlier this year breaking down.

A swath of above normal temperature values roughly 50 to 200 meters underwater is beginning to push towards the surface and strengthen. The swath has been present underwater for some time now; it's possible we could see further warming in weeks ahead. The CFS v2 makes a case for this idea, showing continuous warming in the main ENSO region (3.4) for the next few months. I'm not really keen on getting in with this warming idea- the CFS has proven itself wrong before with warming SST's across the Pacific, and the rapid warming the model is showing in weeks ahead may not verify.

On the chance this rapid warming does occur, the question becomes: Will we see an El Nino for this winter?

If we see the SST's warm enough, then yes, we would see an El Nino. There are numerous caveats with the premise of an El Nino this winter, but I've already explained a few of them above. What we really care about is- would this El Nino transfer into the atmosphere? Based on current projections, I would not think so. Current model forecasts and analog years suggest a cooler than normal upper US, whereas an El Nino would bring about a warm trend throughout the Plains and Midwest.

Time will tell if we actually see an El Nino develop, but right now, I am skeptical of the idea.

Andrew

4 comments:

Anonymous said...

Most likely a weak El Nino. Pacific temps warming, but not to extreme levels. El Nino winter does not always mean a cold/snowy regime for the US. These are just patterns that drive the general setups.

Frank-o said...

A El-nino forming in mid to late January would indeed be very interesting....combined with a
N-NAO and you got the perfect set-up for us here in Northwest NC! Hmmmmmm.........

Eric (weather advance) said...

@Anynonymous
Yes, el nino winters don't always mean cold & snowy for the US because of how the warmer than normal oceanic waters in the equatorial Pacific are orientated relative to North America, usually a central Pacific el nino which favors a stronger than normal Hawaiian low favors a cold & snowy conditions because this like a rock in a stream and with the focus of upward motion over the central Pacific, this supports an anomaly of anticyclonic energy to the northeast near western North America. In combination with a favorable 30 day sunspot cycle & MJO, this leads to an eastern US trough and with a warm AMO in place, we can also get a favorable -NAO as well. However, if you actually do the research into our current pattern, we are in a period of multi-year la nina or cold ENSO neutral which has lasted since 2010, & since 1950, there have only been 2 other instances in which we experienced a multi-yr nina, in the mid 1970s at the end of the last cold PDO & the multi-yr nina following the large el nino of 1997. Those el nino winters which came off of a multi-yr la nina tend to be quite cold in the eastern US likely because the prolonged period of la nina which equates to a charging of heat in the tropical Pacific followed by an el nino leads to a rather large discharge of energy into the mid-latitudes, & over the eastern eqautorial Pacific, (also attracts the MJO towards phases 7 & 8, and climatologically speaking, an upward MJO pulse in phases 6-8 tends to favor a -NAO because the increased lower heights & upward motion lead to stronger blocking near western North America, this in turn forces the polar jet to buckle southward in response & combined with an enhanced subtropical jet due to the upward MJO pulse leads to significant phasing of storm systems in the eastern & central US that also, especially when paired with a warm Atlantic tripole, forces high-latitude blocking to develop in the vicinity of Greenland.) which in turn leads to a series of feedbacks that tends to favor a cold winter in the east US.

dillon shockley said...

LMFAO to eric wow dude..i tried my best to follow that..can u re explain some in dumb terms lol..likeee so the question if a el nino is ahead would eastern and central us see snow?. i live in kentucky..what about that general area