We remain in a rather amplified or ‘blocky’ pattern right now across Europe with two main drivers controlling the movement of air around the continent. Through the second half of this past week, TWO upper lows have played a key role with one to the SW of the UK and the other slowly drifting east across Scandinavia. With the arctic oscillation negative, arctic air has been able to get tapped by the Scandinavian low for the first time in a few months and this is just the start!

These two blocks have held high pressure over the UK but heights from Morocco up to just north of the UK have been strong. The low positioned over Scandinavia has been feeding arctic air south and expanding as well as deepening a trough into eastern Europe but because of the strongly positive height field in the west, the cold was only able to go south and east.

The upper low over NE Europe is now drifting east into Asia now and this changes the playing field to a degree this week. By shifting the large upper low east, this stone gets removed and with a trough digging down over Iceland, this expands the UK ridge northeastward.

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The positive height field remains from Iberia up to the UK and now that the upper low is leaving, so warmth replaces the cold over Norway, Sweden and even Finland BUT because of the upper ridge poking it’s nose up into Scandinavia, this in turn forces even colder air out of Siberia into European Russia, Ukraine and the SE of the continent in coming days. The height field remains too high in the west to allow this cold to drift towards the Low Countries, Denmark and the UK. In many respects, it’s too early in the season for this setup anyway.

Check out the Tuesay morning temperatures across eastern Europe according to the GFS.

Wednesday morning looks colder and this may be underdone given the clear skies that should prevail.

Of course the interior continent ‘usually’ tends to cool first and waters off the continent are indeed warm as you’d expect in late September and given the type of summer it’s been this year, the ridge is likely to try and hold on from Africa up to the UK as long as possible. What’s interesting though is the fact that the cold coming out of Asia into Europe is far colder than you would expect. Could the larger sea ice coverage and the + arctic oscillation over the past few weeks, then followed by the flip, have something to do with just how cold it is? The ECMWF shows an eventually take over of positive heights across Europe in the 5-7 day period ultimately whipping out the cold.

Both AO and NAO are currently negative but are expected to trend positive. Will be interesting to see whether there’s a delay to positive or not.

The reason for today’s title ‘a lot of uncertainty’ is because there is little model guidance which at least hints at what may be further down the road. The first two weeks of October looks no different on the models compared to runs I’ve seen much of this past week and by that I mean, a western ridge/eastern trough, however I don’t think it will stay like that throughout the next 4 weeks and the models will start to shed light on the week 2 through 4 perhaps this upcoming week.

It’s not that I’m trying to wish cast and ‘hope’ for cold but given the pattern, I believe we should see a reverse in the height field at some point through October. Originally I thought the NAO/AO would go negative around this period WHICH IT HAS but I thought the upper air pattern would be opposite to what it is now and through this upcoming week with a western trough/eastern ridge. I guess I should be looking at the type of summer we’ve just had and the feedback of waterm waters to the atmosphere and the bias towards ridging and not troughiness. I’m possibly a few weeks ahead of myself and a little more patience is needed as I feel strongly that the larger sea ice cover, water temps of the N Atlantic, Pacific and arctic as well as low solar activity presents a big winter this year. Given the fact we haven’t even reached October yet, I need to sit back a bit I think and just look at the big picture. I’m not a big fan of models as their just a guide. They don’t hold the answers but I admit I, like most others can get sucked into them too much.

Too many out there go ONLY by the long range models for their own ‘winter forecast’. Let’s just say I’ve had my ideas since mid summer based on many aspects and not on models, others have their winter ideas based on models and only models. I’m guessing there are some that have went back and forth in their ideas a thousand times in the past 2 months simply because the CFS, CFSv2, ECMWF and countless others, are all over the place.

In terms of my overall thinking, I guess it’s promising that we are seeing unusual cold, a highly amplified pattern and more importantly a -NAO/AO which tells me there’s POTENTIAL and indications of what can happen. Another important thing to remember is the seasonal adjustments and the cooling which must take place in the ocean and surrounding waters. With time, the atmosphere will change with the season and so while we have a western ridge and eastern trough now, come November into December. The same set of ingredients will have a very different result, i.e the same -NAO/AO will have deeper, colder troughs and they’ve be positioned differently.

Let’s take a look at the pattern over the next 7 to 10 days and you can clearly see from the below 500mb chart off the ECMWF that we see it get colder over the eastern continent as the ridge builds into Scandinavia but in the later stages of the period, ridging and mild air prevails BUT I would hold off in full buying this idea of warmth completely taking over.

Today

Tue 1

Thu 3

Sat 5

The above chart for next Saturday showing a strong, cold upper low dropping into the SE of Europe could support early snowfall over parts of the Ukraine, Romania and Bulgaria.

Mon 7

Wed 9

As for the surface charts off the ECMWF, notice how skies turn clearer and precipitation clears Scandinavia and eastern Europe through the second half of this week as surface high pressure builds north. As this happens, so fronts sweep a heavy band of rain into Ireland and the UK. Also notice how the 540 line dives southeast as pressures build into Scandinavia as this is pushing the cold air into the Ukraine, Romania and Bulgaria. The low in the SE corner by Friday could bring snows as very cold air wraps around the backside of the low.

Sun 29

Tue 1

Thu 3

Fri 4

Sun 6

Mon 7

Note as the height field rises across Europe next weekend into the early part of the following week, a cut off lows brings heavy weather to Italy and across much of the central and eventually eastern Med. The UK has a much more unsettled theme going by then.

Any Signs Of Cold Coming Down Over The First 2 Weeks Of October?

As we look out into the 2nd week of October, both the GFS longer range and the ECMWF Control and Monthly runs show some troughiness dropping into the WESTERN side of the continent.

The GFS surface chart at 360 hours or around the 14th shows a strong low over Scandinavia but the model shows the 540 line diving south on it’s backside which could mean colder air diving into the UK.

Here’s the GFS 5,000ft temperatures for the same period. The darker blue indicates the -5C line btw. This chart could suggest a wild snow event for Norway, Sweden perhaps extending into parts of north Germany. Snow showers for Denmark maybe?

The ECMWF control shows a decent cold shot dropping into the UK around the 12th.

The ECMWF monthly drops a trough with cold air into the UK around the 13th.

 

While there is a lot of uncertainty in the long range, I thought Id show you the CPC (Climate Prediction Center) 500mb height anomlaies for the upcoming winter and the 2 metre temperatures. Haven’t shown you this yet.

Here’s the 2 metre temperatures.

Now wouldn’t that be great! Those charts by the way are pretty close to what my overall thinking is for this winter overall.

The Jamstec continues to show a nice tripole of warm-cold-warm over the North Atlantic and cold for Europe this winter. It continues to suggest a warm winter for the United States.

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Tags: Europe autumn forecast, europe october forecast, October forecast