Re: do you think they'll upgrade to Cat 3 in 4 PM CDT full update?
Posted by
Chris in Tampa on 8/25/2017, 2:35 pm
I kind of thought they would already. With sonde data and flight level data that has increased, I thought that would be enough. I guess they're looking for that 10 second estimated surface wind from the SFMR instrument that says 115mph. They do usually go with what that has, even though it's a 10 second estimate. The dropsonde is a momentary wind. The original data from the sonde might be every quarter second. (or half, I forget) But then the program that condenses all that into the WMO text output that NOAA then has on their server, I don't know if it does any averaging. Is it averaged over a certain time interval/height it has fallen? I don't know.
102 knots (117 mph) was at 11:58am CDT for the sonde at surface. Maybe since nothing on SFMR yet at 115mph, just 109mph, maybe they will keep waiting until it finally hits it by SFMR.
I thought this might do it too, from another sonde, in prior Air Force mission, at 10:24am CDT:
Average Wind Over Lowest Available 150 geopotential meters (gpm) of the sounding:
- Lowest 150m: 157 gpm - 7 gpm (515 geo. feet - 23 geo. feet)
- Wind Direction: 100° (from the E)
- Wind Speed: 110 knots (127 mph)
Some of these things I think they might normally go with, like these for flight level of aircraft:
30s: 109 kts (125.4 mph)
10s: 112 knots (128.9 mph)
Then again, I forget what some reductions are off hand. 85% wouldn't do it, 90% would.
But they would be making this the first U.S. landfalling major hurricane since 2005. A big deal. So I guess unless we get that SFMR value, even if it were suspect, I guess they might wait.
For Ike, they never went up. I remember that storm. They kept going back and forth as it made landfall and they couldn't find the wind to bump it up to a major hurricane.
I do like consistency, I just don't know concrete examples of other storms where they upgraded.
The Dvorak chart is amazing though:
http://www.ssd.noaa.gov/PS/TROP/CI-chart.html
It's a guide certainly, but still amazing we're this low and at 110mph. Pressure is that of around a category 4. |
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