The major stratospheric warming and breakdown of the polar vortex that began in late December, 2020 has impacted this winter’s weather as I predicted on New Year’s eve. www.dailykos.com/…
The ice storm and extreme cold in Texas this week could not have been forecast six weeks ago but intense cold air outbreaks into the American midcontinent are one of the known possible consequences of the breakdown of the polar vortex. Dr. Judah Cohen forecast a weak polar vortex in early fall based on the lack of ice in the Barents sea region, the build up of snow in Siberia and the forecasts of the American CFS and GEFS models. Operators of the Texas power grid should have been preparing for the possibility of a severe cold outbreak since mid November.
The ongoing catastrophe in Texas www.dailykos.com/… is a caused by the failure to design a robust and resilient energy grid and by gross mismanagement, not wind power or the failure of weather forecasters to give timely warnings to electrical grid managers of the potential of cold weather. Mark Sumner’s Pulitzer Award quality story Texas power grid is working exactly as designed explained how the Texas’ profit driven power system will inevitably fail in extreme cold air outbreaks. This story, however, is not about Texas, it’s about the good news of the impacts of the polar vortex breakdown.
The extreme sudden warming high in the stratosphere that happened in the weeks before and after New Year’s day cause an enormous dome of warm sinking air to form over the polar region. That sinking air slowly worked it way down through the atmosphere towards the surface.
But what’s really cool about what happened is that the warm sinking air was in total darkness and skies were clear. These were perfect conditions for radiating heat out to space from all levels of the polar atmosphere. An enormous dome of high pressure built up over the Arctic ocean. These were perfect conditions for transferring heat out of the lower atmosphere and the top layer of the Arctic ocean and radiating that heat out to space. These are ideal conditions for increasing Arctic sea ice thickness which was near record lows at the end of September, 2020.
Global temperatures are now near the thirty year climate average because of the combination of the extreme polar heat loss this winter with the strong uptake of heat by the equatorial Pacific ocean caused by the La Niña event in the Pacific ocean. This is an extraordinary cooling event. Global surface temperatures were near record highs in September. In just months the cooled to normal. (See top figure).
Moreover, the polar vortex breakdown around New Year’s drove Siberian air towards the north Pacific ocean causing intense storms across the Pacific, into California and western north America. California and the western states got much more rain than would have been expected for a normal La Niña year. This rain was much needed because of the ongoing drought in California and the southwest. And that’s not all.
Notice the red region south of Greenland on the figure above. That’s warm water. There is no cold pool south of Greenland indicating a slowing Gulf Stream and weakening thermohaline circulation. That’s because the major stratospheric warming led to subsidence and high pressure over Greenland and storms over the far north Pacific, the opposite of the catastrophic stagnant north Pacific, stagnant weak Gulf Stream pattern that climate models predict by the turn of the century if we don’t stop emitting greenhouse gases. The polar vortex breakdown brought the cold “beast from the east” weather to Europe but the overturning circulation is going strong this winter. That’s good news. The intense storms this winter in north America and Europe have been destructive, but the large scale effect of the breakdown of the polar vortex has been to cool the northern hemisphere rapidly and reintensify the Gulf Stream system. That’s very good news.
Unfortunately, there’s an increased risk of severe thunderstorms and tornadoes in the spring months of a year with both La Niña and a major winter stratospheric warming. The American CFS model shows a storm track for March running from Texas and Oklahoma through the Mississippi and Tennessee valleys into the mid Atlantic states. There’s going to be a “battle” between warm air off of the Gulf of Mexico and Gulf Stream with the cold Canadian air dropping down over the western states into the plains. The “battle zone” is shown by the green forecast rain belt in the figure above. Expect more severe weather than normal in this region in March and April.
In fact, both the American and European weather models are hinting at the possibility of severe weather in Texas about a week from tomorrow. Of course, the weather models are not good enough to make an accurate forecast a week or more out, but they indicate that conditions may become favorable for tornadoes in tornado alley in about a week. Be prepared.