Review of last recon mission into Nate
Posted by Chris in Tampa
on 10/14/2017, 11:25 pm
|Last Nate mission:|
Before the strongest winds made it onshore, I think the surface winds may have come down a little further. (flight were too, though not as much) There wasn't a large area of strongest winds so it was easy for the strongest winds not to be measured on land. But the SFMR values were coming down before landfall too. There is one caveat though. When the storm turned NNE, the highest winds may have been more south than the due east where recon was flying before landfall. So they might not have hit the strongest winds.
Looking at some of the SFMR values, some of them may have been in too shallow of water. The highest values were often just east of some of the barrier islands. Given where the storm was, the highest wind could be expected to be just east of it.
I picked out what I see to be the highest 10 second estimated surface winds estimated from the SFMR instrument on the aircraft from each pass before landfall.
I was looking at some of the historical imagery in Google Earth. Some of the images make the water look even shallower than default imagery.
I'll have to keep that in mind in the future. I thought the first 92mph suspect reading was over a little bit deeper water.
Here is the highest flight level winds before landfall by the way:
The highest 30 second flight level winds of the entire mission were 86 kts (99.0 mph). Here was the entire mission:
So you can see flight level winds didn't come down much.
As for surface winds, going back to first image, flying toward the east, due east, from the center, here were some of the highest readings in a row, every 30 seconds:
44 kts (50.6 mph)
53 kts (61.0 mph)
57 kts* (65.6 mph*)
64 kts (73.6 mph)
72 kts (82.9 mph)
75 kts (86.3 mph)
74 kts* (85.2 mph*)
75 kts (86.3 mph)
77 kts* (88.6 mph*)
63 kts (72.5 mph)
60 kts (69.0 mph)
This was in the pass that has the southernmost 984mb vortex icon. I would consider these to reliable as there were many in a row. So I would say the intensity was about 85mph then.
As for at landfall on mainland, not counting any barrier islands, depends on if the winds would have been higher just a little south of due east. If they were not, I would say 70mph based on recon. But assuming they could be a little higher in places at the time, or just south of due east where they did not fly, perhaps 75mph.
I'm treating the SFMR as if it were 1 minute sustained, which the NHC sometimes does when setting the advisory intensity, assuming there are higher winds likely and also because that's all they have. I like to see two readings in a row about the same.
As for sonde data, which has momentary winds, including at the surface: They seemed to indicate around to slightly less than the SFMR values. They did seem to indicate higher winds not too far above the surface, of about 10mph or more. You can see sondes here:
There wasn't too many and they could have easily missed the highest winds.
In this thread:
Is Nate a one or two???< Return to message board
- Mark in PC Beach
, 10/7/2017, 9:15 pm
- Review of last recon mission into Nate - Chris in Tampa, 10/14/2017, 11:25 pm
Post A Reply