All posts tagged extreme sea surface temperature anomaly

Mangled Jet Stream + Global Warming + Hot Atlantic Water = Boston Buried Under 8 Feet of Snow

If you deny that warmer ocean temps -> greater snowfall w/ coastal winter storms, you are not a climate denier. You are a physics denier. — from the Twitter feed of Dr Michael E. Mann, Climate Scientist

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Boston just experienced its snowiest month on record and, yes, it really is climate change, stupid. In essence, as Michael Mann notes above, it’s a matter of oceanic and atmospheric physics.

Consider the fact that the ocean surface is warming at an unprecedented rate. Consider also the fact that this observed warming is resulting in a number of powerful south to north flows of air over ocean regions and toward the polar zone.

Over the past month, these powerful warm air flows pushed strongly into both Alaska and Svalbard — causing 20-30 C above average temperatures in regions of the Arctic along the 70 to 80 degree north latitude lines. For Alaska, the warmth was so prevalent and intense that it forced the Iditerod sled dog race to be moved 300 miles north for want of snow and ice. On this past Sunday night in Svalbard, just above the 80 degree north latitude line, temperatures were a balmy 1.2 degrees Celsius. An extraordinary above freezing reading in a land where temperatures during this time of year are typically 20 to 30 degrees Celsius below that mark.

(Anomalous above freezing temperatures in the land of winter dark and chill. Also note the very powerful south to north air flows originating from the 30 degree north latitude line and terminating in the Arctic near 70 to 80 north. These flows exist in both the Pacific and the Atlantic — hugging the coastal zone and flowing strongly northward along a reoriented storm track. Image source: Earth Nullschool. Data source: Global Forecast System Model.)

All this warm air moving north must have an impact. And that impact is to leave Greenland and the eastern North American Continent as the remaining refuge for cold Arctic air that would typically amass over a rather thick pack of sea ice. But that sanctuary for cold is increasingly frail and unstable. For the ice is thinner and itself rests upon waters that are warming. So the cold instead moves to land and to land ice — both bodies with physical properties better able to keep cold during the long winter dark.

So the cold flees its previous habitat in the far north near the pole and instead dives about 1,500 miles south over Greenland, Eastern Canada and the US. In the upper atmosphere, this pattern is reflected by a huge trough in the Jet Stream. One that has been repeatedly identified by the crackerjack research of Dr. Jennifer Francis.

(Very high amplitude Jet Stream wave pattern with strong ridge in the west, very deep trough digging through Eastern Canada and the Eastern US, an a return to the strong ridge pattern over the North Atlantic. Image source: Earth Nullschool. Data source: Global Forecast System Model.)

Such a powerful hot-cold dipole in the atmosphere results in extraordinary atmospheric instability. The deep trough alone would be enough to send storm after storm hurtling toward the Northeast US. Storms born of a fury of Arctic cold coming into collision with oceanic moisture from the Gulf of Mexico and the Atlantic.

It is a pattern that has been fixed in place for a month running. One that has delivered storm after powerful storm to the US northeast along a screaming storm track. And one that has slammed these storms into an unprecedented wall of warmth and moisture.

For not only have warm air flows invaded the Arctic resulting in a highly anomalous displacement of cold air southward for an extended period of time. But ocean warmth in a region of the Atlantic just off Boston has provided extraordinary fuel for these storms once they arrive.

For we have observed sea surface temperatures just off Boston in the range of 8-11 C above average for most of the months of January and February:

(Sea surface temperature anomaly map by Earth Nullschool. Note the highlighted region shows an extreme temperature departure of 11.1 degrees Celsius above average. Data Source: Global Forecast Systems Model.)

For reference, a sea surface temperature anomaly of 2 C or higher is considered to be a rather strong departure. The 11.1 C anomaly in the above image is, for lack of a better term, simply off the charts. In rough translation, this amounts to surface waters in the range of 65 to 70 degrees Fahrenheit only about 200 miles or so off the Massachusetts coastline. A coastline regularly seeing temperatures in the range of 0-28 degrees F. The result is a 40-70 degree temperature departure over a very short distance. By itself, this extreme temperature differential would be an amazing storm generator. But the differential alone only tells half the story.

The other half is a powerful explosion of moisture off this much warmer than normal water. A massive mushrooming of moisture just off the coast. And when this very heavy bank of moisture collides directly with displaced onrush of cold and dry air, the amount of snow that is squeezed out can be staggering.

Record-breaking staggering. 8 feet for Boston in one month staggering.

As Michael Mann so saliently noted, you’d have to be a physics denier to not understand the role of ocean warming in either the warm air invasion of the Arctic in the Oceanic zones, the related displacement of cold air over the eastern half of the North American continent, or the fueling of extraordinarily powerful winter storms along the Northeastern Coast of the US.

And to this point, I leave you with the equally salient thoughts of Bill Nye from his twitter feed: