This decade, the worst drought in California’s recorded history happened in large part due to a formidable ridge of high pressure off the shores of the Pacific Northwest in 2012 that persisted for years in the winter months. This bumped the winter jetstream that brings us low pressure systems and precipitation to the north and away from California, and plunged Southern California in particular into a long, punishing drought.
By strange coincidence, climatologist Daniel Swain published a long post on the research into this subject last December 4th. Strange because that very night the Thomas Fire broke out not far from here, and became a firestorm that visited this property and Upper Ojai, causing vast damage.
But the question then remains as it does now: Will the RRR return? Will we in SoCal go back into drought?
Worryingly, this week the Washington Post reported on the return of the Blob — warm North Pacific sea temperatures — to the Gulf of Alaska. This in the past was associated with the Ridiculously Resilient Ridge, or RRR that brought California the drought.
Throughout early fall, Alaska has been oddly warm and pleasant. The cause of the freakishly nice weather has been massive high pressure anchored over and around the state. One of the strongest on record for fall, this sprawling dome of warm air has helped keep the usual transition to cold stunted.
Since days are still long in early fall across Alaska, the sunny September (and into October) skies have also allowed ocean temperatures in the Northeast Pacific to rise significantly, as well. This has led to a return pool of abnormally warm ocean water in the Northeast Pacific known as “the blob,” and just in time for Halloween!
But scientists are unsure whether the blob will remain a fixture or fade away. If it manages to linger into the winter, the consequences for the Lower 48 could be profound.
Daniel Swain talked about this association in his post of last December: In his usual judicious way, he laid out the leading possibilities, without choosing a single causal factor, but hinting at the associations between the various possibilities.
To date, the strongest evidence appears to implicate unusually warm ocean waters in the tropical western Pacific, which can trigger a hemisphere-scale wave pattern favoring an enhanced subtropical ridge near California. Other work has suggested that unusually warm ocean conditions in the “extratropical” Pacific (i.e. the so-called “Warm Blob” in the Gulf of Alaska) may also be linked to the persistent ridge—though there’s considerable evidence that the atmospheric Triple R caused the oceanic Blob, rather than the reverse. Still others have wondered whether the striking loss of Arctic sea ice in recent years may have played a role, though the evidence supporting this connection remains sparse. Finally, it has also been shown that random variations in the atmosphere can occasionally produce an extremely persistent North Pacific ridge. In other words: the Triple R may be at least partially attributable to “bad luck.”
“Bad luck” in that context means of course that good luck could bring us some other weather than drought. Let us hope. In Alaska, the state’s citizens are enjoying the strangely mild early winter, and wondering too.
It’s still quite early in the cold season, even in the snowy north. For now, it’s a waiting game. Waiting for summer to finally end, and waiting to see what winter might bring. It won’t only have implications for Alaska, but for all of us.