Re: Confirm or debunk??
Posted by Chris in Tampa on 10/11/2018, 5:11 pm
Short answer, I don't see how anyone could know anything about 200 knots. (230mph) I would say no. Mesovortices are probably what your friend heard about: https://en.wikipedia.org/wiki/Mesovortices Directly measuring that kind of wind would be next to impossible and certainly impossible given any of the equipment on the ground there. As for radar, I don't even know if it is capable of picking up on those kinds of wind or how well they measure the wind of mesovortices. Michael did have mesovortices though. Various tweets: First one from NHC forecaster: Here is a loop of the landfall. Jim was in Callaway: As for recon... Nearing landfall a dropsonde (11:17am EDT) at the 881mb level measured winds of 162 knots (186 mph), but that is a momentary wind. (maybe half a second) In that sonde the 925mb level was at 295 ft and the 850mb level was 2,717 ft, so that wind was somewhere in-between there, not at the surface. 914mb level had a momentary wind of 156 knots (180 mph). That was the highest winds measured by a sonde in Michael. The highest wind estimated by the SFMR instrument on an aircraft was 138 kts (158.8 mph) at 1:06pm EDT before landfall. That is a 10 second wind estimate. Although marked as suspect, the NHC used that value in the vortex message. A lot of the high SFMR readings were marked as suspect, I assume automatically. But those winds were the kinds of winds expected in that area they were in and it was far enough from shore in my opinion. SFMR isn't as reliable in shallow water, though the NHC had some doubts. (see discussion below) The highest flight level winds directly measured were at 1:22:30pm EDT with a 30 second flight level wind of 150 knots (173 mph) and a 10 second second flight level wind of 152 knots (175 mph). Here id what the NHC had to say in their 4pm CDT discussion yesterday: "Data from an Air Force Force Reserve Hurricane Hunter aircraft and NWS WSR-88D radar data showed that Michael continued to strengthen until it made landfall around 1730 UTC (12:30 PM CDT) along the coast of the Florida Panhandle between Mexico Beach and Tyndall Air Force Base. The aircraft found peak 700-mb flight-level winds of 152 kt during its final pass through southeast eyewall just before Michael made landfall. There were SFMR measurements of 132-138 kt, but the validity of those observations are questionable since they occurred in shallow water and were flagged. The landfall intensity was estimated at 135 kt (155 mph), which makes Michael the strongest hurricane to make landfall in the continental U.S. since Andrew (1992). The minimum pressure at landfall was estimated at 919 mb, which is the third lowest landfall pressure in the United States. A University of Florida/Weatherflow observing site measured a minimum pressure of 920.2 mb." From: https://www.nhc.noaa.gov/archive/2018/al14/al142018.discus.017.shtml? I disagree with the NHC here regarding: "There were SFMR measurements of 132-138 kt, but the validity of those observations are questionable since they occurred in shallow water and were flagged." The 132 knots was very near land and might have been in too shallow of water.  Without popup:  Here is the flagged 138 knot wind, well away from land, seemingly.  Unless there is some land Google doesn't note or this particular area is shallower than other waters in that area. That was only about 13 miles south of the center of the eye.  More recon images: Location of the highest SFMR estimated wind:  Wider view:  Jim was in Callaway. Just south of there was Tyndall AFB. I would like to point out that most people did not see sustained winds of 155mph. I don't know if there was higher wind than that in a mesovortices. Perhaps, but that will need to be studied. No one would know yet. But I can say that most people did not see 155mph, sustained. Very few would have, assuming that was the maximum sustained wind. The left half of the cyclone would have, in general, less powerful winds than the right for a storm moving due north. Given this storm's movement was NNE (20 degrees) the highest winds would have likely been to the ESE. Not necessarily, it depends on the storm's structure. But this storm was very well organized so that would likely be the case. The storm was moving at 14 mph. While many people get this wrong, storm movement is included in the sustained wind speed. That means that on the other side of the storm the wind will be a bit less. Additionally, surface wind coming in from over the water has no friction. East of the landfall location some people got the full force of the winds coming onshore. On the other side of the storm, where winds were coming from over the land and out to the Gulf, there would be friction. Surface wind would also be less over there for that reason. That excludes tornadoes or mesovortices that could have given people more wind. There doesn't seem to have been many tornadoes: https://www.spc.noaa.gov/climo/reports/181010_rpts.html But tornadoes in hurricanes are usually much weaker anyway and I think more in bands. I do recall seeing a tornado vortex signature on a radar image at Weather Underground, but that happens in the eyewall of a powerful hurricane. It may have picked up on a mesovortex or maybe it was simply due to the high wind. Panama City, and Panama City Beach too, did not see the highest wind. They were on the "weaker" side and wind was not coming in from directly over the water for the most part, although perhaps around the bays. It's important for people to know on that side that they didn't experience the highest winds. Even on the right side of the storm most people would not have seen 155mph. It will take studying the damage to know more. We'll learn more after the season when the storm report will likely be released. A small section of coast, right at the coast near the water, might have seen that. In the landfall public advisory they say: "A wind gust of 130 mph (210 mph) was recently reported at a University of Florida/Weatherflow observing site near Tyndall Air Force Base before the instrument failed. A wind gust to 129 mph (207 km/h) was reported at the Panama City Airport." From: https://www.nhc.noaa.gov/archive/2018/al14/al142018.public_a.016.shtml? So there were high winds, but most people didn't see 155mph. (of course there may have been higher elsewhere and the one station failed) It's important to note that most people didn't see the worst in case another storm made it's way to the region with these kinds of winds. You wouldn't want someone thinking they saw sustained winds of 155mph when they might have been 115 to 120mph, just as an example. This from a storm chaser: Information from NWS about wind: https://www.weather.gov/tae/20181010_Michael At the bottom of this post I have a list of highest winds compiled from NWS. The highest I have seen is 130mph at Tyndall before it failed. That was a gust. Further east the storm should have had stronger winds but there might have been nothing measuring out there. (and might not have survived anyway) I would also like to note, something else I am seeing on TV, that some damage is from wind and some from surge. In Mexico Beach, directly along the coast, some buildings are gone. Only the foundation is left. That is surge. They might have gotten the wind damage too, but surge completely destroyed it and washed the debris away. Then you have a mix of damage, from wind and surge a little further inland. And then of course there is just wind damage even further away. And I wanted to just throw this in somewhere. I don't know if it's possible, but if it is possible to remove fan blades if you have an outdoor ceiling fan, perhaps think about it if you're away from the center of the storm and don't have to worry about a whole bunch of wind, where removing fan blades is the least of your problem. My sister south of Dothan had two ceiling fans that were on an outdoor patio get destroyed. And part of a tree fell down on a fence, but nothing you can do about that. (other than maybe well ahead of the storm cut out anything that is dead or dying and get it hauled away before the storm in case that might help) My sister lives in Taylor for comparison of how far away thr storm was:
From an earlier Public Information Statement : https://forecast.weather.gov/product.php?site=NWS&issuedby=TAE&product=PNS |
123
In this thread:
Confirm or debunk?? - Beachlover, 10/11/2018, 2:51 pm
- Re: Confirm or debunk?? - Skip Wiley, 10/11/2018, 9:29 pm
- Re: Confirm or debunk?? - Beachlover, 10/12/2018, 2:26 am
- Re: Confirm or debunk?? - Skip Wiley, 10/11/2018, 9:29 pm
- Re: Confirm or debunk?? - Spagpusher, 10/11/2018, 5:09 pm
- Re: Confirm or debunk?? - Beachlover, 10/12/2018, 2:27 am
- Re: Confirm or debunk?? - Chris in Tampa, 10/11/2018, 5:36 pm
- Re: Confirm or debunk?? - Spagpusher, 10/12/2018, 10:12 am
- 200 knots=230mph=EF5=debunk n/t - cypresstx, 10/11/2018, 3:56 pm
Post A Reply
This thread has been archived and can no longer receive replies.