Two Thousand Fifteen broke all records for temperature (it was the warmest year in the last 100,000) — and some for floods. Will 2016 repeat?
Right now, El Niño is going strong, and its corollary, the Pineapple Express, is bringing rain to California.
If history is a guide, El Niño, peaking now, will quickly turn into La Niña; then the Atlantic hurricane season could spin up rapidly.
Santa found a heat wave when he returned to the North Pole. Lake Effect occurs in the ocean too. And there are sea surface temperature anomalies in the Atlantic, Pacific, and Indian oceans.
Let’s go Around The World.
Weather Pattern Omni Is Gone (For Now) But Its Effects Live On In Flooded Mississippi River Valley
Weather Pattern Omni has visited the US twice, the last time for over a week. Omni features a deep trough in the west and a strong ridge in the east. Snow in the mountains, flooding rains in the heartland along with tornadoes, and record warmth from the midwest to the Atlantic coast justify the name. The Weather Channel chose to use many different names to identify ‘winter storms,’ but these events were connected and many of them were un-winterlike.
Rivers funnel rainfall to the sea, and though Omni is gone, all its water is not. Flooding has moved from Missouri to the southern states. Eventually all the water will be gone, but it is worth considering whether this is an anomaly or something that will now happen more often.
In general, scientists expect more precipitation as the atmosphere warms. Warm air can hold more water vapor than cold, so there is more moisture to precipitate. That doesn’t mean it will — just that there is the potential for more precipitation.
Probably precipitation patterns will change depending on location. The Mississippi Valley seems especially vulnerable. The jet stream has recently shown a desire to fold up and become stalled. This has two effects:
- The wrinkly jet stream will cause more north-to-south flow. And vice versa. Southerly winds from the Gulf of Mexico are loaded with moisture.
- If the pattern stalls, as it did last week, rains may fall in copious amounts for many days. And it all eventually drains into the Mississippi River.
Pineapple Express Arrives
As Decoded Science reported last week, Weather Pattern Omni, which brought flooding rains and tornadoes to the central and eastern United States, was giving way to a new pattern which featured a low-latitude jet stream across the Pacific Ocean and southern United States.
The new pattern was expected to bring rain to California — and so it has. The phenomenon is dubbed the Pineapple Express because the flow is directly from Hawaii to the mainland. Significant amounts of rain are now falling as far south as San Diego.
The Pineapple Express is directly correlated with El Niño, which is now at its most powerful. California should receive drought-relieving amounts of precipitation.
El Niño And Sea Surface Temperatures (SST) Worldwide
El Niño is still obvious from the SST anomaly chart, but most of the indicators have begun to decline. The last comparable El Niño, in 2010, was followed by a robust La Niña. La Niña, as we have often noted, correlates with active Atlantic hurricane seasons. The next NOAA update on El Niño will be issued on January 14.
Meanwhile the SST anomalies show interesting features outside the tropical Pacific:
- In the Gulf of Alaska, where a major hotspot has persisted for two years until recently, the SST is still slightly elevated, but not so much as to compete with El Niño. The drought of the last several years on the west coast of the US can be linked to this warm water pool which some misguided meteorologist christened ‘The Blob.’ The name caught on. With The Blob waning and El Niño cresting, the widely anticipated Pineapple Express has arrived.
- A very cold pool of water that has migrated slightly westward from south of Iceland remains unexplained. Decoded Science named this The Anti-Blob (why not?), and it has contributed to the warm winters in Europe recently by inducing a southwest flow over the continent.
- The waters in the Gulf of Mexico and subtropical western Atlantic are noticeably above normal. This could have ominous implications for the hurricane season if it combines with La Niña.
- The water temperature in the South Indian Ocean is well above normal, but there is no tropical cyclone activity as of now. The season usually begins to ramp up in January.
Lake Effect Snow Depends On Wind Direction
The first serious Lake-Effect snow around the Great Lakes accompanied the change in weather pattern. Different wind direction brings snow to different cities: Chicago, northeast; Cleveland, northwest; Buffalo, west-southwest.
‘Lake Effect’ can also occur adjacent to the ocean if you don’t mind torturing the term. Lake-Effect snow is now falling on Cape Cod as the cold north wind traverses the warm Atlantic water. Since the Cape is low and narrow, the effect only brings a few inches of fluffy white as opposed to a few feet in upland areas downwind of the Lakes.
Santa’s Sauna — Well, Not Quite
The weather pattern that brought unusual warmth to the east coast of the United States on Christmas Eve pushed warm air all the way to the north pole. Arctic temperatures above 80 degrees latitude were more than 20C above average (some reports had temperatures exceeding freezing) on New Year’s Eve. Though arctic winter temperatures have fluctuated and stayed substantially above the long-term average in recent years, this warming was unprecedented.
New Year, New Perspective On Climate Change
After the warmest year since instruments became available with which to accurately measure temperature, it is instructive to see if the warming is really significant.
Instrumental observations date back about 150 years, but data from tree rings, bubbles trapped in glacial ice, coral reefs, and ocean sediments provide an accurate description of temperature going back hundreds of thousands of years.
Temperatures have fluctuated between glacial and interglacial times with a period of about 100,000 years. Theory accounts for this pattern by incorporating various changes in the earth’s orientation and orbit. The change from interglacial to glacial temperature is about ten degrees C, but at no time did the temperature change more than a degree per thousand years.
The recent observational record shows that the temperature has risen about one degree C in the last hundred years, much faster in the last few decades. This increase has been linked, as tightly as is possible with physical theories, to the burning of fossil fuels and subsequent release of carbon dioxide into the atmosphere.
The earth has had the capacity to reverse the smoldering caused by long-term changes in celestial forcing mechanisms. It is not clear that anything can reverse the relative conflagration that results from burning coal, oil, and natural gas if it goes on too long. Anyone who would like to see what an out-of-control greenhouse effect leads to is invited to visit the planet Venus — temperature about 500C.
New Year, New Schedule For Weather Around The World
Beginning with this article, Weather Around The World, heretofore a weekly feature, will be published once a month, on the first Tuesday. Naturally, Decoded Science will report on important weather events as they occur. And as always, we’d like to know what’s happening where you live.