Really good summary
Update: Rectos has done a stunning visual of this:
Storm Frank 30/12/2015
Storm Frank brought gales and heavy rain and more flooding to the NW of Britain and especially for parts of Ireland. It was perhaps fortunate that the storm did not cross directly over the UK but swept north towards Iceland and the Pole. The northward track was due to a developing blocking high of 1047mb over Scandinavia which directed the jetstream and attendant depression north.
The “cause” of Storm Frank was an increasing temperature gradient over the Atlantic which increased the power of the jetstream.
Polar and Tropical airmass collision
Polar air pouring into the Atlantic from a cold Arctic Canada and Greenland met Tropical air moving up from the Gulf. This contrast was increased by a cooler Mid-Atlantic and a warm Gulf Stream creating a large pressure difference.
The ingredients for a perfect storm were created as the mother of a jetstream embraced her baby Frank in the Mid-Atlantic. Infant Frank…
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