As a front slips east there is a threat of some sleet and snow across England and Wales on Wednesday.

Such is the delight of being a forecaster in such a situation 😉 its very difficult to predict the height at which rain turns to snow, and at what temperature.

Here's the forecast skew-t for Birmingham at midday Wednesday (from Weatheronline.co.uk)

Notice how wet it is right the way through the atmosphere?

Now, freezing levels at midday are about 875mb...not too low and it's likely precipitation is rain at that stage.

But now look at the situation at 6pm Wednesday.

Still saturated, with a freezing level now at around 925mb, and falling.

By midnight the freezing level is down to 950mb, but notice how drier air is now below 700mb. However, it's still moist and so precipitation is still likely.

The forecast precipitation type from the GFS for 21Z on Wednesday evening calls for snow Pennines and Welsh hills. But this is likely to be underplayed.

The forecast snow for 6pm to midnight shows a similar story with snow on hills.

Interestingly the UKMO EURO4 makes more of the snow at low levels in the Midlands, but keeps it over the Pennines and hills of Scotland.

So, ultimately what does this mean?

Well as a forecaster one could stare at model charts all day, but much of this comes down to local topography and forecasting knowledge.

We've gone with the idea of a wet and cold day; starting in the west and north in the morning, then rain edging slowly east through the afternoon and evening.

The rain turning to snow over the hills of Wales and northern England, and then during the afternoon as colder air arrives and the freezing levels drop, some sleety, wet snow is possible in norther, central and southern parts of England.

The result is likely to be snow on the hills of the same area, and perhaps evening some wet, slushy stuff by the morning over low ground in these areas.

It may well be the East Anglia and southeast England get into the sleety, wet snow conditions by Thursday morning, because as the forecast skew-t for Heathrow at 6am on Thursday shows, the air is still saturated and the freezing level is down to 975mb. That could cause some significant icing problems for aircraft.