FLORENCE on final approach...
Thursday 13th September 2018
We have four (and a half, one might say) storms under way. I'll summarise them from east to west, then focus on the main theme across the reporting area, Hurricane FLORENCE.
The ‘half storm' is Disturbance Thirty Six centred 350 miles south-east of Corpus Christi, moving west-nor'west at 10 knots. The environment is still marginally favourable for this to make a guest appearance as a tropical storm before landfall somewhere close north of the mouth of the Rio Grande tomorrow. Regardless of development, the disturbance is starting to produce strong winds, heavy squalls, and rough seas across the northwest offshore leases and will be a rainmaker for the middle and upper Texas coast through the weekend.
Some good news from Tropical Storm ISAAC. Now just 80 miles east of Dominica and westbound at 18 knots, ISAAC will cross the northernmost Leeward Islands in around 4 hours from now. The skew-whiff vertical structure has started failing already and this may be in shreds by the time it reaches the area around Dominica and Guadeloupe. A reconnaissance flight reported that squalls have diminished overnight and maximum wind speeds are down to 40 knots. If this welcome weakening continues, the system may just bring some gusty squalls, heavy rain and thunderstorms. This could have been much worse.
Disturbance Thirty Seven deepened overnight and has become Subtropical Storm JOYCE. This is centred 950 miles west of the Azores and moving south-west at 5 knots. JOYCE is expected to loaf about aimlessly for a few days before turning harmlessly north-east bothering fish and the odd sailor but not approaching land.
Another fish storm, Hurricane HELENE is 1100 miles south west of the Azores headed north at 12 knots. HELENE is weakening now with the last wind speed report being down to 75 knots. This will accelerate north to north-nor'east over the next few days while weakening and losing its tropical characteristics. It could bring squalls and gales to the Azores on Saturday and possibly some remnant filth to the extreme west of the British Isles and Irish Republic early next week.
Disturbance Thirty Eight is passing the Cape Verde Islands westbound at 12 knots but showing no real zest for life. We'll have a better idea tomorrow.
So, to Category 3 Hurricane FLORENCE. This has weakened during eyewall replacement, but only barely and may even rally a little before landfall. Now just 175 miles east of Wilmington, NC headed north-west at 12 knots, the forward scouts of rain squalls are already bringing heavy showers and gusty winds to the Outer Banks and will soon be felt ashore quickly followed by tropical storm force winds from Wilmington to Cape Hatteras. Later tonight or very early tomorrow morning, the centre of FLORENCE is expected to arrive on the coast of southeast North Carolina. At this time, sustained hurricane strength winds can be expected. There is still a strong likelihood that this will stall on the coast and prolong the onslaught of hurricane force winds, catastrophic rainfall and dangerous storm surge for anything up to 12 hours. Then, as FLORENCE eventually pushes inland, the primary concern will shift from the surge and the wind to the torrential rainfall and dangerous flooding that is likely to occur due to the system's slow forward motion.
Stand by in south western Texas, the Leeward and Windward Islands and along the south eastern seaboard. This will be a miserable and agonising 24-48 hours for many.