Following a pretty benign September and 1st half to October, the pattern has shifted and come alive. The doldrums have gone and so too is the unusual warm, dry weather, replaced by record or near record rainfall on the west coasts of both N America and Europe.
The below 2m temp anomaly for Oct 2021 clearly shows the northern blocking with warmth over cold.
Michael Ventrice
Warm October for North America and N Europe.
Michael Ventrice
Michael Ventrice
From dry to wet…
Like 2009 and lesser extent 2010, we’ve seen a similar type of pattern evolution with prolonged settled, warmer than average conditions followed by a near stationary front with warm conveyor connecting the UK with tropics. The result, a 24-48 hour deluge over Cumbria, S Scotland.
Upwards of 400mm of rain fell within 44 hrs and over 800mm in October at Honister, Cumbria. A complete flip from the abnormal dryness of recent months.
It’s interesting to see how this has happened in the not so distant past and we know what followed the 2009 Cumbria floods and again, to a lesser extent in 2010. Could the whole evolution of the pattern then but returning now?
The warm pool between Azores and Iberia likely enhanced the rainfall for the Western UK upslopes.
Met Office
The MJO has been unfavorable for Europe cold lately hence the warmth. However I believe change ‘may’ be under way with an eastward progression of the MJO-rossby wave train seen by the models. High pressure which has been a common feature lately over the Baffin Straits/W Greenland could continue strengthening and build heights north.
Michael Ventrice
All in all I think the jet stream remains highly active between Canada and Europe with jet strengthening towards mid month, deeper a couple of deeper lows into the UK/Ireland. All the while Greenland and northern blocking becomes more established.
To summerise…
Chilly, unsettled early to mid November followed by colder 2nd half to the month with AO/NAO turning negative.
ALL THE ABOVE SAID, WHILE I BELIEVE A COLD, NORTHERN BLOCKED PATTERN WILL EVOLVE, I FEAR DELAY. IT’S HAPPENED SO MANY TIMES BEFORE AND I CANNOT RULE THAT POSSIBILITY OVER THE FORTHCOMING 4 WEEK PERIOD.
CFSv2 for November 2021
Tropical Tidbits
Tropical Tidbits
Tropical Tidbits
FEATURED IMAGE CREDIT: Seija Ropponen @RopponenSeija
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