EUROPE: Classic October Weather Is On It’s Way

Written by on September 29, 2014 in Rest of Europe, United Kingdom & Ireland with 0 Comments

Good morning! Changes are being seen by all models this upcoming 7-14 day period with the NAO dropping back towards neutral then negative. This to me suggests more wet than cold. Saying that the AO is going negative too say perhaps I should watch the potential air masses coming down closely.

I’ve stated for some time now that October should wind up warmer than normal but a good deal wetter than September, then a turn to even wetter during November. I haven’t however mentioned much about cold. Do I see any cold this autumn? I think we’ll get a few chilly air masses following and wind and rain whipping from the Atlantic. The Atlantic sure will become more involved as we progress deeper into the season. This of course is a rather fickle transition period when cold builds to our north while warmth tries to fight on. The clash between air masses produce stronger jet streams which start their southward migration as cold swells.

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Look for ‘short spells’ of cold NW winds on the backside of lows which may bring hill snow and frosts but I think on the whole, the warmth which gets lifted north AHEAD of these lows, outdo the chill which follows and so warmth should win out.

The latest runs of both ensemble and operational GFS/ECMWF shows a much more active period coming week 2 (next week) and probably starting at the end of this week but the CFSv2 fails to see a flip to a negative NAO.

I want to point out that we have to see the availability of cold air to our north in order to make a call as to whether it’s going to get real chilly or not. Right now, I don’t see an true cold blast until we reach late November or more so, December. I think there’s less arctic connection with each passing low and so it’s more maritime not arctic or polar influence this autumn but we always need to watch late in autumn when cold does become more of a player.

Here are those week 2 periods off ECMWF and GFS operational and ensemble.

ECMWF day 3-10

Credit: AccuWeather Pro

Credit: AccuWeather Pro

GFS 7-14

Credit: AccuWeather Pro

Credit: AccuWeather Pro

GFS Ensemble day 7-14

Credit: AccuWeather Pro

Credit: AccuWeather Pro

Interestingly the CFSv2 only weakens the positive or the deep negative over Greenland and positive over the UK but it fails to see the negative NAO even out to late October..

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wk3_wk4_20140925_z500

As for this week, well it’s not looking too bad, a touch cloudy with light showers or rain over parts of Northern Ireland, Ireland and Scotland but head further south and or east and your under the influence of that high. Still feeling warm in the late September sunshine with highs topping 21-23C in the Southeast.

Notice as we head into mid week (Wednesday), fronts attached to Icelandic lows will bring increased cloud, rain and breeze to the north and northwest but again, these frontal systems weaken considerably as they progress SE.

Look for cooler air behind this weakening boundary which passes through Wednesday with high pressure sliding in and clearing out the clouds and with slackening winds, look for a greater frost threat in the North, possibly Central parts Wednesday night into Thursday.

Come late week and while high pressure temporarily slides in, another system gathers out over the Atlantic in this west to east upper pattern. By Friday a particularly potent low and front swings in and that brings a change as stronger (gale-force) winds blow across the northern and western UK as well as heavy, driving rain. Warm in the Southeast of England thanks to some sun and stiff SW winds ahead of the front.

Then into the weekend and we find ourselves on the backside of that front and NW winds will draw colder air which means potential for hill snow across Highland Scotland and frost. Another deep low appears to follow Sunday.

Credit: AccuWeather Pro

Credit: AccuWeather Pro

Credit: AccuWeather Pro

Credit: AccuWeather Pro

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ecmwfued---europe-96-A-mslpthkpcp_white

 

Credit: AccuWeather Pro

Credit: AccuWeather Pro

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ecmwfued---europe-168-A-mslpthkpcp_white

Admittedly, we must watch how chilly the air is aloft as this may catch myself and others out with regard to heavy snowfall above 2500 to 3500ft. Down at low levels, it’s likely to be a cold rain and suppressed temps but nothing wintry.

I’ve done a video but because of a poor internet connection it’s not uploading. Will try to get it posted later for you.

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