Storm Austen is closing in on Brittany, with forecasters warning that tempest-force winds will slam into the French coast within 24 hours.
According to Thursday's Meteo Consult bulletin, a disturbed south-westerly flow is building ahead of the low-pressure system, which is deepening rapidly over the nearby Atlantic. At midday UTC on Thursday, Austen sat 380 nautical miles west of the Breton coast, with a central pressure of 983 hectopascals.
Overnight, the storm intensifies further, dropping to 978 hectopascals as it tracks south of Cornwall in the small hours. The flow swings from south to south-west and turns tempestuous off the Breton headland and the entrance to the English Channel. By dawn, the storm has swept across all of Brittany's northern coastline.
Friday brings little relief. The south-westerly flow shifts to west-north-west, still tempestuous, as Austen's centre closes on the Pas-de-Calais by midday, with pressure recorded at 984 hectopascals.
Saturday looks calmer at first, with a disturbed south-westerly flow accompanying the passage of a warm front during the day. But that calm is short-lived.
The south-westerly flow strengthens markedly again on Saturday evening and overnight into Sunday, with the cold front of the disturbance expected to pass through around 5am. A strong, unstable west-north-west flow follows once that front clears.
For any fleet preparing to cross the Atlantic solo, this is exactly the kind of system race routers watch closely. Timing a departure around a low this deep, under 980 hectopascals at its peak, is no small task.
NZ sailors and followers of the IMOCA and Ultim classes will recognise the stakes. Weather windows like this often dictate not just comfort but safety in the opening days of a transatlantic solo race.
The bulletin offers no comfort for an early, clean getaway. Conditions are forecast to stay unsettled right through the weekend.
