csnavywx

Climo wasn't a help with this storm. Underforecast and underanalyzed shear in a shallow region under the outflow layer on the SW side of the storm about 2 days out from landfall helped disrupt the inner core just enough to bring it down a notch. A cat 3/4 landfall was the best call at the time, given the data available. I'm not sure the surge or flooding problems would've been any less even without the weakening period though.

Cranky being a crank with that chart. It covers the entire period from 8/31. Most of that error was built up during the initial RI period when the storm went much further north than forecast. After that, it was clearly better.

Frictional torquing likely playing a part in keeping it offshore. The torque component can become dominant in such weak steering flow and when running at a shallow angle to the coast (as Florence has).

ASOS at ILM reported 56G91KT (62G105mph). Multiple reports of 100+ mph gusts along the coast to the east as well and sustained 80-90 just east/southeast of ILM.

Frictional convergence doing serious work as the eye tries to come onshore. It was able to spin down the outer wind maximum, which has allowed the inner eye to consolidate and contract.

That high level shear is really showing up well on IR and the 250mb charts now. However, as the NHC discussion stated, it abates between 06 to 12Z tomorrow. Until then, expect more weakening as that shear is now able to impinge directly on the core.

Ah, you're right, didn't see the loop. My bad for not double checking -- 25-30 looks about right based on the most recent pass. Inner eyewall looks like it is gone finally. Still multiple wind maxes though.

Mostly agree, though Florence hasn't suffered what Ike did -- a total inner core disruption when it passed over the Yucatan. It never really recovered from that. The surge on this one is going to be ridiculous because of the insane fetch, strength and duration. The radius of hurricane winds is getting a bit out of hand.

That shallow wind shear just below the outflow level on the southwest side stays there until late tonight or tomorrow morning on the GFS, then abates. Might have another opportunity for strengthening then.

That last recon pass - wow. There's like 3 cocentric eyewalls and a big stripe of hurricane force surface winds like 80-100 miles away from the center. Still obviously a decaying inner eyewall too. The center "calm" area has grown to 60-70 miles wide. The wind field has grown too big to strengthen quickly unless that big second eyewall can consolidate a bit and rob the rest of the wind maxima. Bottom line, the size is likely to continue growing, even if the max winds really don't.

This storm loves its ERCs. The outer eyewall in the last MIMIC image is massive. That thing has to be like 50-60 miles wide. We could have a giant truck tire by the end of the day or tonight.

That southern outflow channel is especially impressive.

Florence is looking pretty chunky on satellite. Been gorging on all that meaty OHC. Wouldn't worry about the satellite appearance too much. This is probably 125-130knots atm. It also has some time to complete another EWRC and expand even more if it decides to do so.

This is the nightmare scenario I was afraid of. That trend from 3 days ago never did stop and now with the midwest ridge helping out, we've got ourselves a coastal staller. An earlier stall isn't necessarily good either, because while there will be some extra time for wind shear to weaken it, I don't expect the shear to stay indefinitely and the Gulf Stream will abate some of the weakening associated with upwelling, especially if there actually is some slight southwest motion.

We're dangerously close to this thing not quite making it onshore on the last few runs. This weakening trend of the WAR is bad news. This also has implications for the track forecast since a stronger/offshore vortex will not be pushed by just the weak lower level southeasterlies and will have a propensity to stay offshore due to weak southerlies or southwesterlies aloft. The individual EPS members show just that and a decent minority now don't have landfall for several days, hovering offshore instead. Also a minor note since I brought up the EPS -- it's still displaying a small left of track bias. This morning's position is again on the right edge of the envelope. It's a relatively small track error and may not end up mattering, but given the situation later on, it might make a difference to landfall times, since the right side of the envelope is favoring closer to Morehead City, NC and a longer stall/loop.