Destructive IRMA - strongest of three hurricanes across the region
Thursday 7th September 2017
From west to east
Small Hurricane KATIA is the least mobile of three hurricanes on radar today. Loafing about, around 180 miles east of Tuxpan, Mexico, this has a current hurricane severity index rating of 8 (3 for size and 5 for intensity) which is producing 70 -90 knot winds. Conditions are favourable for further development and this could reach category three before landfall. This is expected to drift west and beach close south of Tuxpan late tomorrow night without significant impact on the offshore leases to the north thanks to protective frontal activity which has ring-fenced the northern Gulf. The fact that this developed in the limited space available in the southern Bay of Campeche demonstrates continued storm-fertility in the Gulf. The season is far from over for the Gulf, I'm afraid.
The latest observation of destructive Hurricane IRMA gave measured wind speeds of around 145 knots and still freshening. IRMA is expected to remain a category 4 or 5 hurricane until it interacts with Florida. Currently centred around 200 miles east-sou'east of the Turks and Caicos islands headed north west at 13 knots, the storm is expected to move through the Turks and Caicos Islands and the southeastern Bahamas today. The eye of IRMA has suffered some wall deterioration overnight and a slight reduction in consistent wind speeds but this is rather more of a wobble from land interaction than a serious weakening. This is expected to recover an HSI rating of 39 (17 size, 22 intensity) fairly soon as it heads for Florida straits by late afternoon on Sunday when it will turn. There is less certainty amongst the agencies on the turn today, with European modellers returning to a swipe along the west coast of Florida in the far eastern Gulf, whilst the US modellers (and the Canadian guy) sticking to route 1 - a sweep of the east coast headed for a landfall late on Monday in South Carolina. The latter would seem more logical given pressure gradients but in any event, Florida will be impacted heavily whichever way IRMA goes. This remains a very nasty storm indeed.
Hurricane JOSE is now 850 miles east of the Leeward Islands headed west at 15 knots. This is a well defined and tight little storm which is developing quickly and expected to become an intense hurricane later today. This is expected to reach an HSI rating of 21 out of a possible 50 points (8 size / 13 intensity) but with a fairly limited tropical storm force windfield of only 150 miles. JOSE is moving in the general direction of the Leeward Islands however likely to turn early, but still bringing tropical storm force winds to the Leeward Islands again. Any nudge to the west could result in the centre moving over the islands before turning but we have a couple of days to see a more confident forward path.
A new Disturbance Thirty Eight is around midway between the Cape Verde Islands and the Caribbean located moving to the west-nor'west at 13 knots. This system is expected to turn more to the north well to the east of the Caribbean and has little chance of meaningful development, which is a nice break for everyone.
Stand by for hurricane conditions across the north eastern Caribbean, Bahamas, Florida, southern Texas and central tropical Atlantic.