(Atmospheric El Nino Index by WSI shows a very strong atmospheric response is unfolding. But long range weather maps, long range NOAA forecast shows an atypical pattern for El Nino. Image source: WSI.)
They say that a picture can paint a thousand words. How about a graph that exceeds 100 El Ninos? It may not jump out at you at first, but that’s what we’re looking at above.
This graph, provided by Weather Channel Affiliate WSI (and based on atmospheric data collected by NOAA) represents intensity of atmospheric response patterns to El Nino. Typically, this means cloudiness at the Central Pacific Equator, the propagation of near equatorial westerlies, atmospheric wave propagation in the Jet Stream, and storm track amplification. In other words, teleconnections.
On the left side of the above graph, we see positive and negative numbers indicating standard deviation correlation to an ENSO neutral state. Push into 2 standard deviation range either high or low and you’re getting about a typical El Nino or La Nina response from the atmosphere. And ever since June we’ve been in the 3 standard deviation or about top 10 percent of El Nino response range.
That’s a pretty strong ocean to atmosphere signal. But it pales in comparison to what’s being predicted. Looking ahead, the Euro weather model then pushes us all the way up to a 4 standard deviation event (or top 1 percent of atmospheric response rates) by early-to-middle August. This is an extreme response to El Nino. One that could have some amazing impacts come Fall, or possibly sooner (see North Atlantic storm discussion below), especially when we take into account some of the added impacts of human caused climate change. Should such a response emerge, both the US Southeast and Gulf Coast could be in for some extremely severe storms.
(A rather deep trough for Summer-time swings down through the Eastern US. Image source: Climate Reanalyzer.)
For the US, such a strong atmospheric response to El Nino forcings would tend to indicate a powerful trough digging in through the Eastern half of the country, even during summertime. And while we do see a rather strong trough for this time of year setting up over and extending down from the Hudson Bay region of Canada, we do not see an overall suppression of summer-time heat and potential for greatly increased precipitation that would typically occur under such a pattern, as yet.
Instead and somewhat oddly, the pattern has kicked energy out over the ocean — fueling the North Atlantic storm track and powerful oceanic cold core cyclones at a time when such events should be rare. Yesterday, a gale hammered Scotland and Ireland, kicking up seas west of England into a frenzy of 30 foot swells. To say this event is odd for summertime is a bit of an understatement. Sans tropical storms swinging north, the higher Latitude regions of the Atlantic are typically calm this time of year.
Winter-Type North Atlantic Gales During Summer
But living in typical times we are not. Greenland melt is ramping up. And so we see the start of a Heinrich Event-like cool pool in the North Atlantic. Call it a baby Heinrich or a precursor or whatever you like. But it’s there. And it’s anomalously cool. And it’s going to influence the weather regardless of whether we like it or not. It’s an event related to both fresh water flow into the North Atlantic and an associated decline in the strength of the Gulf Stream. This odd summer North Atlantic storm generation is then, perhaps, due to a teleconnection between the strong atmospheric signal of El Nino and the underlying signal of human-forced climate change. Such a teleconnection would tend to shift the El Nino related trough a bit eastward and result in an amplified North Atlantic storm track. Which is exactly what we are seeing.
(It looked like a North Atlantic winter storm. But this screen capture of 30 foot swells due to a powerful gale off England was taken late last night [August 3rd]. For those familiar with typical summer patterns for the North Atlantic this should be a moment that inspires head-scratching. One with an uncanny similarity to patterns predicted in a recent paper by Dr. James Hansen. Image source: Earth Nullschool.)
NOAA long range forecasts are also picking up the signal of powerful storm track intensification over the Gulf Coast and the Southeastern US. Such a prediction hints at a strong storm track running diagonally across the Atlantic from Florida to England and aligned with a trough edge running through that broader region. It’s a pattern that could put England in the firing line for severe winter storms yet again. For the US, the upshot is powerful storms slamming a region from Texas through the Carolinas from September through February. Florida, Coastal Georgia and the U.S. Gulf Coast are particularly hard-hit in the forecast. But we also shouldn’t rule out some strong bombs impacting the Mid-Atlantic region before they tear off across the ocean.
No Significant Drought Relief for California?
Sadly, the atmospheric response to El Nino is not pushing forecasts for a wet winter for the US West Coast. Monsoonal moisture hits the US Southwest during September and October, but barely touches California in the forecast. The moisture pattern then retreats eastward. Heat and dryness are particularly focused in the region of Washington, Oregon, Idaho and Montana. Abnormal warmth is also predicted to remain in place over Alaska.
(NOAA long range forecast finds little drought relief for the US West Coast this winter even under the influence of a predicted powerful El Nino. Image source: NOAA CPC.)
This pattern appears to indicate that the NOAA models are calling for the Ridiculously Resilient Ridge and the hot Blob of water off the US West Coast to mostly remain in place. An overall very bad forecast considering El Nino’s predicted intensity and the currently indicated strength of atmospheric response. It may be that cooling in the North Atlantic associated with Greenland melt and Gulf Stream weakening is having such a powerful impact on the Jet Stream that El Nino cannot over-ride — instead solidifying the Pacific Ridge to Atlantic Trough fixed atmospheric wave and dumping its teleconnection influence into the firing range that the North Atlantic is steadily morphing into.
To this point, it’s worth noting that long range model forecasts of this kind can carry with them a rather high error bar. The ocean-atmosphere forcing of the predicted super El Nino will likely result in some rather dramatic wrenchings of the climate system. And for such an El Nino to fail to over-ride the West Coast block would have some very serious added impacts on down the line.
(Please support publicly funded, non-special-interest based science, like the fantastic work provided by NOAA and NASA, without which this report and the reports provided by Climate Reanalyzer, Earth Nullschool, and WSI would not be possible.)