Re: RMS HWind
Posted by Chris in Tampa
on 9/19/2017, 5:09 pmMessage modified by board administrator on 9/19/2017, 6:41 pm
|Edit 1: Vortex message was updated to say it has a 10 nautical mile wide eye as of 3:42pm EDT vortex. (and was also reported in 5:12pm EDT vortex)|
Edit 2: A later pass (when 5:12pm vortex occurred) found category five winds estimated by SFMR around 6 to 7 nautical miles south to SSW of the center. That would make the width of category 5 winds at that time to be about 12 to 13 nautical miles from NE to SW quadrant.
Edit 3 (final edit): Next pass, around 6:19pm EDT, had category 5 winds over around 14 to 15 nautical miles, from SE quadrant, to center, then into due north quadrant.
The information in this post will change. Please read carefully.
The problem is that the inner core changes more often. Right now the eye is 10 nautical miles wide, so the potentially catastrophic winds are over a small area. However, if an eyewall replacement cycle occurs, which no one can forecast, you're going to have a much larger area of dangerous winds. While often storms temporarily weaken when an eyewall replacement cycle occurs, unusually this year we've seen storms not do that. They maintain their strength and then continue strengthening. If this occurred before impacting the Virgin Islands and Puerto Rico, a large section of these islands could be impacted by the most dangerous winds. (The entire island of St. Croix may get a direct hit from the strongest winds either way) If the NHC released information about the most dangerous winds, it could change dramatically, in a very short amount of time.
At the moment, obviously subject to change, the category 3 winds are over about a 25 nautical wide area when looking at NE to SW quadrants. Category 4 winds over about a 15 nautical mile wide area.
As for category 5 winds, about 10 nautical miles from the center into the NE quadrant. I can't give a width, including into the SW quadrant, because when the plane passed through the SW quadrant it went through so fast it only had a couple 140 mph SFMR estimates there. It doesn't mean the winds aren't there, it's just the plane passes over so fast. You would expect a little lower wind there, but it's likely stronger there, they just missed it.
So if you gave these numbers now, and an eyewall replacement cycle occurred just before landfall, a much larger area might be surprised by the winds. While obviously people should not be looking at the forecast track this precisely, some people likely will. They may believe that because the strongest wind field is so small, they could take a chance and not prepare, thinking they might not get hit by it. They could be surprised by a powerful core that could double or more in size. That would be my guess as to why the NHC doesn't give more information about the inner core. When you focus too closely on that, you're taking an extremely dangerous risk if you think you can avoid it, and I think with details about the inner core, some people would take that risk when looking too closely at the exact forecast track for the center point, rather than cone.
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RMS HWind< Return to message board
, 9/19/2017, 11:31 am
- Re: RMS HWind - Chris in Tampa, 9/19/2017, 5:09 pm
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