Tuesday, September 11, 2018

Florance day 7

9-11  Still no changes....still unsure where she goes after "landfall".

Scratch any references to the Wilmington to Wrightsville in previous posts.  I meant Wilmington to Morehead City, thinking thats where Wrigtsville beach was. But Wrightsville and Wilmington are essentially the same area. 

Still looking at a Wilmington hit. Worst part between Wilmington and Wrightsville.  Big question is once it gets there or just short of there, where does it go.  The stall and SW move into SC are popular now with the models.  Seems odd to me.

We saw some changes in the structure today -an eyewall replacement which saw the diameter of the eye go from 12 miles to 34 miles.  Best seen on mimic. Watch the inner eye wall dissolve and be replaced by the outer one.
This is what the eye looked like late this afternoon.
Some fluctuations in strength will occur prior to landfall due to these eye wall replacements.  Its a sign of a mature storm

Tracks are still taking the storm to somewhere between Wilmington and Diamond Shoals, depending on which model run.  Then once it gets to that area, sometims it slows then progresses inland, sometimes it loops, sometimes it drifts south.  There are no steering currents around and to say where exactly it will end up is just impossible.  That it remains in one area will help it weaken - if over land it will weaken rapidly, whereas if over water, it will churn the water up and cool it off, taking away its fuel. My new favorite model site is the U Albany site which has a great summary of all the operational tracks.  These are the 0z and 12z runs. I highlighted the area where the storm will slow. Black line is the NHC forecast. 



Much of the east coast had coastal flood warnings last night due to an easterly fetch persisting. Hwy 12 was overwashed.  Add to that swells from Florence and those warnings remain in effect for the tidewater area and Chesapeake Bay.  Now add in 20-30ft waves as mentioned in the discussion from the Morehead NWS office ( link  ) and a storm surge of 9 to 13 feet, winds over 100mph, staying along the coast will be life threatening.  This isn't just for 3 hours or 6 hours - the storm is modeled to sit for 24-48 hrs.  Now do I believe that?  Not sitting offshore, but I could see a situation similar to Harvey. 

A quick look at the latest HWRF and HMON while I'm here.  These are the US hurricane models, designed to deal with hurricanes. The Deterministic/Operational models like the GFS don't get intensity very well as I described last night.  HWRF has 120kt winds right before landfall, which is 138mph, sustained winds, not gusts.  Gusts might be 160mph.  It keeps the storm moving though.

And the HMON which is roughly 110mph at landfall, having dropped from 110kts to 90kts on the approach.  I add 5mph as the area with the higher winds is already ashore in this frame.
As I wrap up, there seems to be some degradation to the storm, perhaps another eyewall replacement like last night.  Or a lot of prayers.









No comments:

Post a Comment

Storm 3 - could be the one! (spoiler, it was)

 2/9  Set up is an upper low over TX that heads northeast into TN valley and then transfers off the coast. At the upper levels, there's ...