I had to travel from NE Suffolk to Lichfield, Stafforshire on Boxing Day evening. The Met Office had a yellow alert for snow so I packed a shovel just in case and kept up with the internet weather reports.

The Met Office didn't escalate to Amber, the weather reports of snow were not happening, and the traffic cameras were 100% clear so I was confident the weather would not be a major factor.

As I set off it was 3 deg C and raining heavily. The temperature fell to about 2C around Norwich, and there was some sleetiness there, but then increased to around 4C at Cambridge, where the rain eased off. Near Huntingdon the temperature increased again to around 6C, and there was a second band of heavy rain. As this abated, the temperature began to decline slowly, falling to around 2C near Kettering. There was snow lying on the high ground just east of the M1, which was enveloped in fog, and it was raining heavily, indicating that warm air had become wrapped up in the system. The temperature decreased to 1C on the M6, and there was some sleet, which turned to snow at J9 of the M42. The last 10 miles to Lichfield were made in light snow at a temp of -1C, with slight settling on the roads, and there was about 2cm of icy crust at the destination.

My parents who live in the Lickey Hills south of Birmingham reported initial heavy rain at 2pm, turning to heavy snow at 3.30pm, which later settled to about 3inches, before reverting to rain and being washed away. This apparently happened to a lesser extent at Lichfield and some snow remained and converted to ice.

10 miles further north at Rugeley, snow depths were markedly higher, and there was localised traffic disruption.

All this is consistent with an intrusion of warm air that was underplayed by models, resulting in an over-forecasting of snow depths and particularly extents right up to the nowcasting time frame. I guess it just goes to show how hard it is to forecast in these cases where the rain/snow situation is marginal.


Brac