The wind is blowing from the East in this case. The source region cold and dry, so when the air crosses the sea, it will become unstable. This is favourable for a convective disturbance to develop, although this situation is less common than a cold air outbreak from the north.

Yes, in the series of AVHRR images, we can see cloud streets developing in the Easterly flow all along the coast of Norway.

There are two areas of enhanced convection and increased cloudiness in the imagery: during the day of the 4th February, a cyclonic disturbance developed and tracked towards Iceland. At 00Z there is also an area of stratiform cloud off the coast of Finnmark - this corresponds to a surface trough analysed in the pressure field at 00Z

Yes! In previous studies (see the reference sections) it has been observed that a land - sea temperature difference of 20C or more is associated with polar low occurrence. In this case, the land temperatures are around -20C, and the sea temperatures are a few degrees above zero.

Not necessarily! In maritime airmasses from the north, the ice edge provides the temperature difference. In this case, the land-sea boundary provides the same condition for a continental airmass.

The air flowing from Scandinavia is stable, and even sea temperatures (close to the coast) are unlikely to be high enough to break through the inversion. If deep convection is to take place, further forcing would be required. However, as the air continues to flow out over the sea away from the coast the (relatively) warmer sea surface temeperature will be able to provide sufficiently high temperatures to initiate convection in the North Sea.