BMS Tropical Update 9/25/2017 12 PM CDT

By: - September 25th, 2017

Maria is weakening at a greater pace than previously thought, and it will now likely have little impact on the insurance industry as it stays a safe distance from land and begins to race across the Atlantic on Wednesday. This is great news and should provide the insurance industry with a much needed break before the next area of tropical trouble shows up in the southwest Caribbean late next week.

Maria Final Forecast
Today’s main weather story continues to be Maria which is a weak Category 1 hurricane 315 miles southeast of Cape Hatteras, NC.  She is moving north at a slow 7 mph  towards the North Carolina coast. Satellite imagery shows Maria’s inner core being ripped apart by dry air and wind shear. A large, cloudless area now exists where you’d typically expect intense thunderstorm activity to be. Dry air being forced into Maria’s inner core by strong winds aloft (wind shear) is the culprit, and its weakening influence won’t let up anytime soon.

Notice the lack of deep convection on in the center of Maria and on the west side of the center.

Another factor, as discussed yesterday, is that Maria is tracking over the cold wake of Hurricane Jose, which has also clearly helped in Maria’s deterioration.

Sea Surface Temperatures off the North Carolina are below 26 degrees C (78.8 F) which is not conducive of tropical convection. This is a direct result of the cold wake left from Hurricane Jose last week. Over the next 12 hours Maria will be moving over this colder water which will further weaken Maria into a tropical storm.

The confidence in Maria’s track forecast continues to improve with there now being very little probability of landfall (less than 20%). However, a weakening ridge of high pressure over New England will guide Maria close enough to the Outer Banks that I expect some of these coastal communities could see tropical storm-force winds (40+ mph). However, with Maria rapidly falling apart, it is also very possible that these conditions will not be experienced. The biggest hazard at this time is the strong onshore wind that will pile up water on the ocean side of the northern Outer Banks and on the bay side of the southern Outer Banks. Storm surge of a couple feet in both of these areas is expected. Maria’s impact should be limited to the coastal areas, however, as the inland areas of North Carolina likely won’t even see rain over the next few days.  At this time I don’t expect that Maria to cause enough PCS loss for North Carolina to be designated as a loss state, but her Puerto Rico impacts have already placed her in the record books.

As Maria moves slowly northward, it will continue to weaken and perhaps even stall just east of the Outer Banks as the steering currents weaken. An approaching upper level trough that is currently moving across the central plain states should then shoot the storm rapidly out to sea at the end of this week.

Next Tropical Trouble
The southwest Caribbean certainly seems to be the next area to watch for tropical development. The following is a look at the ECMWF Probability of Tropical Depression formation for Thursday, October 5.

The long range ECMWF ensemble are sniffing out a general area low pressure in the Western Caribbean Sea late next week.

In the meantime, enjoy the lull in tropical activity. I’ll provide new updates if I feel there is any threat to the insurance industry.

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