Hi MiamiensisWx - Thanks for the comments and the compliment on the post, photos and website. I completely respect your opinion... I am not swayed in my estimate... but I do respect your position. I am still completely confident that, during Andrew, maximum sustained surface winds at my home were 125kts, with peak gusts between 145-150kts.
I do completely agree with your assesment of Andrew's eyewall dynamics during the landfall period. The HRD re-analysis windfield does a good job of describing Andrew's overall surface wind distribution, and you are correct in identifying that the highest 'ambient' surface winds were likely right near the coast, about 4-5 miles south of my home. That said, the actual 'strongest' surface winds were observed between 4-6 miles inland, in the communities of Naranja Lakes, Leisure City and Pinewood Villas. These winds were not part of the ambient flow, but were produced by extremely intense, high-speed, transient convective cells that developed over the northern eyewall, rapidly intensified while rotating through the western eyewall, and finally decayed in the southern eyewall. These cells produced incredibly violent microbursts, which augmented the ambient winds, resulting in very narrow streaks of peak gusts between 175-180kts with 5-10 second durations. These winds produced this type of damage...
In their early stages, as these cells rotated from the northern through western eyewall, several of them passed directly over my neighborhood/home, as is evidenced by the following sequence of radar images during Andrew's landfall period...
In this sequence, the first transient (I've labeled A1-5) develops just offshore the King's Bay area and rotates onshore. At position A2, the northern portion of this transient is over my neighborhood. Also note, at this same time, the observer at the Tamiami airport (farther inland, about 4 miles due west of my home) reported that the anemometer needle became "fixed" at the high end of the scale... 110kts... for 3-5 minutes before the instrument was destroyed. He observed that conditions continued to deteriorate for an additional 30 minutes after that. Over the next seven minutes, between positions A3-A5 the transient reaches it's peak while moving over the communities of Homestead and Florida City. Also, in position A4, the next transient has already moved onshore and is again directly over my home. This next transient coincides with positions A4.1 and A5.1 which indicate the location of the NHC/TPC at the exact time that they recorded their 142kt gust (albeit at 40m), which disabled the anemometer....note that the NHC/TPC is actually outside of the transient and is north of my home by about 5 miles.
In this next sequence, which picks up from where the previous leaves off, the next transient (B1-5) has already moved onshore and is past my home on it's way south through the western eyewall. During the next 8 minutes this cell explodes and between positions B3 and B4, reaches a peak directly over the Naranja Lakes/Leisure City area. It is likely that this is the cell that produced the 175-180kts gusts, resulting in the incredible wind damage observed in the photos above. At position B5, yet another transient has developed in the northern eyewall and can be seen approaching the southern end of Key Biscayne.
In this last sequence, the cell that developed near Key Biscayne (D1-5) is now rotating onshore, again, directly over my home at position D2. This transient goes on to intensify and affect the extreme western portions of populated Dade county, over the Redlands area.
In conclusion, I completely agree that the complexity and dynamics of surface windfields, especially within the eyewall of extreme tropical cyclones, are very difficult to estimate and I would add that it's almost as difficult to understand the nuances to the way damage occurs within areas affected by those extreme winds. All that said, with my home's location very near the RMW in the northern eyewall, the persistent development of intense convective elements that rotated across my neighborhood, the incredibly steep gradient Andrew was producing (from 992mb at Miami International to 922mb in the Naranja area... a 70mb drop in just over 20 miles), the rapid forward motion of the storm which was augmenting the steepness of the gradient, the rapid intensification producing a strong isallobaric component to the gradient, several other wind readings (in addition to the ones already mentioned) very near to my home... 154kts (at time of failure) three miles to my south-southwest; 148kts one mile due west; 139kts (at time of failure) two miles west-southwest; 149kts (at time of failure) six miles west-southwest... (here are those wind readings shown in the
NHC preliminary report), and with my numerous experiences and observations in other tropical cyclones, I will stand firmly by my estimate of 125kts gusting to 145-150kts at my home.
-=Michael=-
www.tropmet.com