We continue to watch the unfolding cool down this week that should present at least some with snow, especially eastern parts later Wednesday and Thursday.

The trouble we have currently is the moisture rich west and east wind that has both Southwest and Northeast Britain nervous about additional flooding. Strong west winds are blowing across Wales and South, central England with heavy pulses of rain while east winds blow in heavy rain for eastern Scotland.

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Temperature wise, it’s fairly comfortable just now and through tomorrow, it remains much the same but by Wednesday onwards, as the low drops off the South Coast, that’s when east winds entrain some of that colder continent air and thus snow levels should drop.

Here’s the ECMWF surface charts for today through the end of this week.

24 hrs

By Thursday the low is down over France while the return flow continues to drag air in from Germany and Denmark. Realfeel temps will likely feel like it’s below freezing for the first time this winter. Quite amazing when you think about it.

72 hrs

Surface conditions look good for Thursday with less rain and wind but the cold will be in place and following a night around or below freezing for many, expect daytime highs to struggle, especially if there’s any lying snow.

90 hrs

Here’s that cold air those easterlies are pulling in at the 850mb level on Thursday.

Here’s the latest ECMWF snow chart through 90 hrs.

NAO Goes From Neutral To Positive

While the AO remains negative, the NAO is going positive according to the GFS ensembles. That’s not good news for cold weather lovers here in western and indeed central Europe as mean trough shifts west from the UK out into the Atlantic with ridging setting up over the heart of the continent as we head towards February. Doe it necessarily mean mild here in the UK, no and that’s thanks to the cold not only coming off a frigid North America but also off Greenland too and so despite the expected continuation of the Atlantic flow, there is still at least a chill in that WSW mean flow. The down side is, there appears to be less chance of cold easterlies.

I stand by the 1994 analog Joe Bastardi of WeatherBELL has been going with which is a cold one for the UK. I also stand by the fact that the atmosphere is colder in February than in December and there’s a greater chance at seeing snow, even without the best of pattern setups. In other words, these seemingly poor snow lover patterns, can throw surprises our way, especially when the source regions of our weather is about as cold as you’ll ever get (North America).

The models are consistent at bringing a westerly flow back into the UK by this weekend with the next pretty strong Atlantic low which unfortunately looks likely to present MORE HEAVY RAIN. While milder air pushes in ahead of the system’s arrival and as stated previously, that flow won’t necessarily be a mild one once the cold front is through as cold air will have been crossing the North Atlantic. We could see some rather chilly air and snow levels still down to fairly low levels.

120 hrs

Check out this 850 temp chart for 144 hrs.

Yes, the model sees the ‘WILD WSW FLOW’ AS COLD AS THE EAST FLOW this Thursday! Remember where that air is coming from…

Closer look at 850 temps over UK for same period.

Note the thicknesses on the surface chart.. snow is possible with this cold flow, despite it being out of the WSW.

To prove what I’m trying to get at, here’s the 150 hr ECMWF snow chart!

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