A record strong and prolonged +NAO between May and August helped drive one of Europe’s hottest summer’s in the last 100 years while Greenland shivered it’s coldest since 1997.
The cooling of the North Atlantic has almost certainly helped cool Greenland’s summers down and helped enhance this past summer’s deep Greenland trough and Europe ridge. Other factors of course also have to be factored in.
So, the cool waters have helped support low heights and cold over Greenland…
June
Mid November sees warming North and Central Pacific but remaining cool around Greenland.
What if waters go back above normal? A recent flip to a -NAO pattern has helped bring heights above normal over Greenland and thus warm Greenland and surrounding waters. How significant could warm waters surrounding Greenland be?
Current SST’s.
The general understanding is that when waters are colder than normal in the North Atlantic and particularly surrounding Greenland, the tendency is for low heights (trough) (+NAO) while warm waters favour high heights (ridge) (-NAO).
With a more distinct warm-cold-warm North Atlantic skin temperature profile the potential for a Greenland blocking high may have increased.
Not that simple
If only it was that simple right? Assuming that this warming isn’t brief and it hangs around for the meat of the season, the combination of the above and a modoki El Nino and wet autumn in a low solar cycle may have increased our chances for a colder mid and late winter pattern.
Another big factor to consider is the strength and behavior of the polar vortex. It too shows promising signs. It’s weak and fluid and that is forecasted to continue with further weakening which means there’s a chance of displacement, split or even complete collapse.
SSWE’s are said to be more likely in low solar years like seen in 2009-10.
Why mid and late winter? SSWE’s typically occur late December through February and feedback from ocean to atmosphere is stronger as the winter season matures.
Elongation of the stratospheric #PolarVortex before a wave-2 attack?
Latest GFS is in with anomalies here –> https://t.co/WtGIVzOie5 pic.twitter.com/SfgyrqxEYF
— wxcharts (@wxcharts) December 2, 2018
GFS continues to predict bodily displacement of the #PolarVortex (PV) into Eurasia & a complete evacuation out of North America. I like to say where goes the PV so goes the #cold air. This temperature animation of the polar stratosphere says it all. Likely the focus of next blog. pic.twitter.com/pBqisrhVPO
— Judah Cohen (@judah47) December 2, 2018
Still thinking potential exists for a more substantial #polarvortex disruption second half of December. One pulse of vertical energy transfer predicted for first week of December but second one also for mid month and based on model spread could be larger than currently predicted. pic.twitter.com/DCXPSmgMT9
— Judah Cohen (@judah47) November 28, 2018
CFSv2 members starting to lock onto possible Sudden Stratospheric Warming Event during the latter half of December. The 18Z cycle (Green lines) seems to lock it in during the final week of the month. This is still noise, but could turn into news if the model holds steady. pic.twitter.com/T5qhnA20TO
— Michael Ventrice (@MJVentrice) December 2, 2018
So, the table may be getting set but what meal shall nature serve up remains open for now.
This coincides with my long term idea which states a cold mid and late winter for the UK and Northwest Europe.
FEATURED IMAGE: nevereverro/Getty Imagsing Wallpaper
Recent Comments