By 15Z the low has reached a mature state, with winds likely to be exceeding 45kts in places. Using our knowledge of its evolution up to now, and the information from models, we must decide what is going to happen in the next few hours

Look through the images below and note how the low centre has moved since 06 UTC. Use the data viewer to note down the wind speed and direction at 500, 700 and 850 hPa at each time, near the low centre position. Then move to the next page.

View Data

00 UTC on the 5th

Surface low position at 0608 UTC

At 1240, the surface low position is now at approximately 66N, 01,40E. It has travelled around 170 nm on a bearing approximately 240 degrees, with a speed of about 28 kt!

By 1517, the low centre can be identified clearly. This time, in just under 3 hours, the low has moved on a bearing close to 180 degrees, and has travelled around 70 nm. Its speed is approximately 25 kt.

The Hirlam model shows that the low position at 06 UTC is located close to the axis of the 500hPa trough, and is consistent with the general MSLP field. It lies ahead of the cold air which is approaching from the East, but is well correlated with the PVA area shown by the Met Office model.

By 12 UTC, the low position is ahead of the trough axis, and the movement appears to be consistent with the large scale flow of the 500hPa contours. The T+12 vorticity advection fields show that the PVA area has also moved westwards, and the low is still associated with a high PVA area. It is also in the area of lowest T500 values.

The forecast frame for 18 UTC shows that the upper trough axis is likely to remain behind the low position, while the low itself has begun to move southward, again consistent with the forecast 500hPa flow. It is now at the intersection of the coldest T500 values, and the lowest geopotential height of the 500hPa surface. We can see that by 18 TUC a shallow trough is forming to the SW of the 15 UTC low position.