2 Separate HIGH’s Dominate Week Ahead… Warm Pacific/Cold Atlantic Is Reason -NAO Is No Show 2 Winters In A Row

Written by Mark Vogan on March 15, 2015 in Rest of Europe, Spring 2015, United Kingdom & Ireland with 0 Comments

You have to go back to November for the last time the NAO went negative but for a brief few days this week, it’s back negative.

This is a superb upper air pattern for cold to get delivered into the UK from Siberia.

Credit: AccuWeather Pro

One big problem, there’s NO truly cold continental air to get pulled in hence the disappointment for some hyping this as a cold pattern. Reason? Strongly positive AO has bottled all the cold stuff back up over the pole.

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Polar vortex is strong over source region. This makes for milder mid-latitudes.

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This is the second consecutive year where the North Pacific was warm and North Atlantic cold, this does not favour Greenland blocking but a stronger jet. That stronger jet I believe it part of the reason for the pretty cold AMO signal currently and there’s a question mark regarding whether this is the beginning of that multidecadal flip from warm back to cold or whether it’s temporary.

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As a result of that stronger jet coming off North America and the cold N Atlantic, we’ve had another strongly positive NAO and indeed AO winter.

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The most recent ‘cold winters’ occurred during firmly warm North Atlantic years with a colder PDO signal. When BOTH PDO and AMO are cold, then colder winters are more likely to occur over West Europe like we saw in the 1960s and 70s.

Atlantic

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Pacific

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THIS WEEK!!

The saving grace for us seeing at least some winter this year has been that strong east QBO and weak El Nino which appears to be strengthening as we head for summer.

As for the upcoming work week, HIGH PRESSURE dominates. We start off the week with the strong Scandinavian high dominating, drawing in chilly air from distant Asia. However, as the week progresses, so a more Azores sourced high builds in from the SW and this should bring some warmer air in thanks to sunnier skies but sunny skies gives way to starry nights and thus frost!

GFS surface through the next 6 days.