IRMA set for Florida strike and JOSE second blow for Leeward islands

PM Friday 8th September 2017

From west to east.

Hurricane KATIA is now centred 115 miles east of Tuxpan has intensified with maximum winds of over 90 knots and is now starting to head south west at around 4 knots. Landfall as a category 2 hurricane with HSI 12 (4 for size and 8 for intensity) and 95- 100 knots winds is expected tonight when, in addition to the wind and the surge, very heavy rainfall is expected to cause flooding and mudslides. KATIA has a fairly tight 70 mile windfield but a powerful inner core of hurricane force winds over a 25 mile radius.

Hurricane IRMA is now 425 miles south east of Miami headed west-nor'west at 12 knots. The HSI rating has decreased slightly to 34 (17 size and 17 for intensity) after a slight wobble from land interaction but this is temporary and it is expected to rally again in the next few hours to 36 (17 for size and 19 intensity). There may be another period of eye-wall deterioration tomorrow as the outer 200 mile windfield interacts with Cuba, but IRMA has sufficient momentum to recover and it is still expected that landfall will occur on Sunday morning as a high category 4/low category 5 hurricane with 130 knot winds gusting to 160 knots. IRMA will make a handbrake turn in the Florida straits and head north-nor'west to run more or less along the centre of the Florida peninsula, expected to pass 35 miles west of Miami then Orlando on Monday morning, and about 35 miles west of Jacksonville around noon on Monday. IRMA will still have access to warm water from its broad windfield so is unlikely to weaken substantially until the eye reaches the border with Georgia. There is some chatter of a nudge west, but not yet convincingly explained, so we will stick with this albeit worst case scenario for most and in any event, we are talking tens of miles rather than hundreds. As things stand, hurricane impacts will be felt all along the peninsula to the Georgia border and on both east and west coasts. Severe damage from wind is inevitable as well as a predicted severe tidal surge, particularly in Biscayne Bay. A reduced storm surge is expected across southwest Florida, where winds will from the north as IRMA passes otherwise, there is little in the way of good news to report.

Hurricane JOSE is centred 420 miles east-sou'east of the northernmost Leeward Islands headed west-nor'west at 17 knots. JOSE has just been buzzed by a reconnaissance aircraft which has found a more robust eye, stronger winds and cat 4 strength and will remain a powerful hurricane for the next few days. More worryingly, the storm centre was found to be further south than previously charted which reduces the previously hoped-for 70 to 80 mile passing distance from the north-easternmost Leeward Islands to almost zero. If this path is maintained, this will be a cruel second major hurricane strike on Saturday to rub salt in the wounds left by IRMA. Considerable uncertainty still surrounds JOSE after passing the Leeward Islands but all pointers seem to head north into a period of aimless wandering.

Disturbance Thirty Eight is centred around 750 miles north-west of the mouth of the Amazon, moving to the west-nor'west at 15 knots but remains poorly organised. No threat of development just now.

Disturbance Thirty Nine has been identified over west Africa and is expected to turn early into the eastern Atlantic which we'd all like.

Stand by for hurricane conditions in Mexico, Cuba, Florida, the Bahamas and - for a second time, the Leeward Islands.