The weather phenomenon - warm air from the Iberian plateau - could be pushed towards north-west Europe and spark a six week heatwave with temperatures of up to 30C.
After one of the dullest and wettest Junes since records began, things have only got rainier in early July, and despite above-average temperatures last month, there were only 138 hours of sun - the seventh June in over 80 years.
A spokesperson for the Met Officer said: “To the north and west of the UK, marine temperatures are above average, likely as a result of the warm and settled spell experienced across these areas during May and early June.
“This additional warmth will act to moderate any cooling influence from further west.
“For July-August-September, above-average temperatures are more probable than below-average values.”