It’s been a splendid day across the vast majority of the UK across the North Sea to the Low Countries up into Denmark and Scandinavia and the rest of this week is looking largely fine, dry, warm and settled with the Azores high dominant but it’s the polar low which continues to be seen by the models, now leaving northeast Canada that will be the game changer late this week into the weekend.

Make the most of the sustained spell of warm, settled conditions because as the NAO trends towards the positive side of neutral, so the heights lower over much of Europe allowing fairly deep lows to influence the UK/western Europe weather pattern starting this weekend and appears to last through next week.

I am particularly interested in a low which will cross Greenland mid week and sets it’s sights on Iceland Friday into Saturday, deepening on approach. This system will have some very cold air attached and while strong to gale force winds will likely be a significant feature, the most noteworthy aspect to this storm which pressure down to the mid 970s in millibars, could be the cold temperatures and SNOW.

Check out the depth of the low and it’s howling northerly winds Saturday morning along with heavy precip also.

Here’s the upper chart and 850mb temps. The upper low is literally positioned directly over top of the surface low and this looks to be a very well organised and unusual storm for late August even though this fairly high latitude can and does seen deep lows at this time of year. It’s the cold that comes with it which could well grab weather headlines this weekend bringing a rare late August snowstorm to Iceland.

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Check out these 850mb temperatures. With organisation and depth to this storm, the cold at 5,000ft could well transfer down to much lower levels, supporting snowfall to lower levels.

Both ECMWF and GFS continue to show widespread snowfall over Iceland and as the system pushes east, it even whitens the mountains of southwest Norway.

ECMWF

GFS

The ECMWF continues to show a NW flow with outbreaks of rain across the Northern and central UK Sunday and temperatures may struggle to get much above 12 to 15C over much of Scotland with a brisk NW wind taking the edge off even those readings. This would most certainly be the first taste of autumn since the cold days back in May.

Here’s the surface/precip chart at 144 hours or Sunday

As for the 850mb temps… yes that’s the 0C line at 5,000ft back. Light snow over the tops of the Scottish mountains? western Norway? Well the model seems to think so.

Over Southern England and Wales as well as much of Ireland, highs Sunday are likely to be up into the 16-19C range, keeping in mind that the sun remains high at this time of year. May want to grab a jacket, especially in the North where the wind will be stronger.

As for the 7-10 day or next week, the models continue to currently show a mainly ‘zonal’ or west to east flow across the UK and much of the west and central continent to commence September. It’s not only going to be a lot more unsettled but considerably cooler compared to this week.

Here’s a couple of charts from the ECMWF to show you the general setup next week.

ECMWF Surface/precip

168 hrs (Mon)

204 hrs (Tue)

240 hrs (Thu)

 

ECMWF Upper chart/850mb temps

168 hrs (Mon)

216 hrs (Wed)

It’s a rather unsettled and cool look for not only Ireland and the UK but also the northern France, the Low Countries, Denmark up through particularly Norway, Sweden and Finland. Hot sunshine remains over the Med and far eastern Europe.

The GFS NAO ensemble is trending down and could level off on the positive side of nearer neutral which would support a zonal flow in the 6-10 day.

The setup next week appears to be a good indicator as to what to expect through the majority of September but don’t be surprised to see some short lived warm, sunny days followed by much cooler days too. I continue to believe we’re heading for an unsettled, up and down month which averages out near normal for both rain and temperature.

Here’s the latest CFS 500mb height anomalies for September.. largely zonal…

Temperature Anomalies

As for October and November. The latest CFS charts has turned around from the cold October and November which I tended to think would happen. Remember in recent posts I alluded to a the fact we could see a cold October but warm, wet November. I stand by that idea given current and projected SST’s, ENSO and the natural feedback with ocean-atmosphere through the transitional period from summer to winter.

The NAO should be firmly positive along with the AO during a good chunk of November which will help build the arctic reservoir similar to what we saw during November 2009 with the flooding rains and mild temperatures. We all should know well what winter followed. I also want you to remember that the first half of December in 2009 was warm and wet, then it turned around sharply around the 15th.

The model now shows warm for both October and November but a turnaround in December which has a look to 2009 but I think October may be quite a cold month followed by a warm, wetter November then a return to cold in December.

CFS 500mb height anomalies

October

November

December

The model clearly sees the feedback of those warm northern waters into the heart of winter.

January

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