21 December 2017
The Met Office global temperature forecast suggests that 2018 will be another very warm year globally but is unlikely to be a new record due to a moderate La Niña in the Pacific.
The Met Office forecasts the global average temperature for 2018 to be between 0.88 °C and 1.12 °C, with a central estimate of 1.00 °C, above the pre-industrial average period from 1850–1900. This corresponds to an increase of between 0.28 °C and 0.52 °C, and a central estimate of 0.40 °C above the 1981–2010 long term average of 14.3 °C.
Professor Adam Scaife, head of long-range prediction at the Met Office, said: “2018 will be very warm globally but is unlikely to exceed the recent record, set in 2016.”
The 2018 forecast is based on the key drivers of the global climate, but it doesn’t include unpredictable incidents such as a large volcanic eruption which would cause a temporary cooling. Professor Scaife added: “For example, Bali’s Mount Agung, which has recently experienced modest eruptions, could cause a temporary but significant drop in global temperatures if it undergoes a major eruption in the coming year.”
The Met Office's forecast for the 2017 global mean temperature agrees closely with the latest observations of global temperature so far this year. Data from Jan-Sep 2017 shows the global mean temperature is 1.05 °C above pre-industrial levels.
The forecast for 2018, including the range of uncertainties, again places the coming year amongst the warmest years on record: 16 of the 17 warmest years on record have now occurred since the year 2000.
Dr Doug Smith, Met Office research fellow, said: “For 2018, the global temperature will remain high, but the current La Niña conditions suggest that average temperatures will be around 0.1 degrees lower than we would otherwise expect in 2018.”
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
The chance that El Niño conditions will be in place across the tropical Pacific by the fall is about 65%, and close to 70% by the winter,
pstarr wrote:I forget; was it el nino or nina that was associated with the "Ridiculously Resilient Ridge," the persistent region of atmospheric high pressure that occurred over the far northeastern Pacific Ocean.[1]
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
Subjectivist wrote:Maybe that El Papa you guys were talking about a while back will happen after all?
https://pubs.giss.nasa.gov/abs/sh03500i.html
Abstract
During the warm early Pliocene (∼4.5 to 3.0 million years ago), the most recent interval with a climate warmer than today, the eastern Pacific thermocline was deep and the average west-to-east sea surface temperature difference across the equatorial Pacific was only 1.5 ± 0.9°C, much like it is during a modern El Niño event. Thus, the modern strong sea surface temperature gradient across the equatorial Pacific is not a stable and permanent feature. Sustained El Niño-like conditions, including relatively weak zonal atmospheric (Walker) circulation, could be a consequence of, and play an important role in determining, global warmth.
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
Temperature, winds, and cloudiness across the tropical Pacific were mostly neutral in August 2018, but they gave hints that support model forecasts of a transition to El Niño by later this fall (50-55% chance) or winter (65-70% chance). Below the ocean surface, a wave of warm water was spreading eastward, boosted by periods of weak trade winds.
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
Subjectivist wrote:Maybe that El Papa you guys were talking about a wile back will happen after all?
https://pubs.giss.nasa.gov/abs/sh03500i.html
Permanent El Nino during the Pliocene: Sediment cores taken in the east and west equatorial Pacific show that the present-day surface temperature gradient existed only during the past 2 Myr or so, and was most likely not present during 2-5 Myr ago. This equatorial temperature gradient is eliminated during present-day El Nino events, and this was therefore termed the Pliocene "permanent El Nino". We suggested that this may have been caused by "atmospheric superrotation", which refers to westerly winds at the equator, moving at the same direction as the earth rotation, but at a faster rate. Specifically, with Brian Farrell, we suggested that such superrotation may have been caused by stronger/ reorganized atmospheric convective activity at the equator due to the warmer climate of the Pliocene. The stronger convective noise excites atmospheric Rossby waves which propagate poleward, inducing westerly momentum at the equator, weakening the equatorial easterlies and therefore causing a permanent El Nino [1]. With Nathan Arnold, we then proposed a resonance mechanism between the propagating Rossby waves and the induced westerlies, potentially leading to an abrupt transition to a superrotation state, and perhaps even to a permanent El Nino [2]. Finally, Nathan showed that warmer tropical sea surface temperature, indeed leads to stronger convective "Madden-Julian oscillations" in the tropics, which may excite enhanced Rossby waves [3].
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
Synopsis: Though La Niña is favored to continue, the odds for La Niña decrease into the late Northern Hemisphere summer (58% chance in August-October 2022) before slightly increasing through the Northern Hemisphere fall and early winter 2022 (61% chance).
Below-average sea surface temperatures (SSTs) persisted during April across most of the central and eastern equatorial Pacific Ocean [Fig. 1]. Over the past month, the Niño index values decreased, with the latest weekly values ranging from -1.1°C to -1.5°C [Fig. 2], which are quite negative for this time of year. Subsurface temperatures anomalies (averaged between 180°-100°W and 0-300m depth) remained negative [Fig. 3], reflecting an extensive area of below-average temperatures from the surface to ~100m depth across the central and eastern equatorial Pacific Ocean [Fig. 4]. For the monthly average, low-level easterly and upper-level westerly wind anomalies dominated the equatorial Pacific. Convection remained significantly suppressed around the Date Line and was enhanced over the Philippines [Fig. 5]. Overall, the coupled ocean-atmosphere system reflected the continuation of La Niña.
The most recent IRI/CPC plume average for the Niño-3.4 SST index forecasts borderline La Niña conditions during the Northern Hemisphere summer, with increasing odds for La Niña into the fall [Fig. 6]. Similar to last month, the forecaster consensus predicts Niño-3.4 index values to weaken into the summer, but remaining below the threshold of La Niña (Niño-3.4 values equal to or less than -0.5°C). In the near-term, westerly wind anomalies are predicted for mid-late May which supports the weakening of below-average surface and subsurface oceanic temperatures in the coming months. However, much of the model guidance is also hinting at a re-strengthening of La Niña conditions again in the fall and upcoming winter. In summary, though La Niña is favored to continue, the odds for La Niña decrease into the late Northern Hemisphere summer (58% chance in August-October 2022) before slightly increasing through the Northern Hemisphere fall and early winter 2022 (61% chance; click CPC/IRI consensus forecast for the chances in each 3-month period).
This discussion is a consolidated effort of the National Oceanic and Atmospheric Administration (NOAA), NOAA's National Weather Service, and their funded institutions. Oceanic and atmospheric conditions are updated weekly on the Climate Prediction Center web site (El Niño/La Niña Current Conditions and Expert Discussions). Additional perspectives and analysis are also available in an ENSO blog. A probabilistic strength forecast is available here. The next ENSO Diagnostics Discussion is scheduled for 9 June 2022.
To receive an e-mail notification when the monthly ENSO Diagnostic Discussions are released, please send an e-mail message to: [email protected].
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
theluckycountry wrote: My town was all but cut off for 2 days this week.
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
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