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We're not quite done with Eta yet, but here's what I have as the best track:
AL292020, ETA, 58,
20201031, 0000, , LO, 14.8N, 68.5W, 25, 1007,
20201031, 0600, , LO, 14.9N, 69.8W, 25, 1007,
20201031, 1200, , TD, 14.9N, 71.1W, 30, 1006,
20201031, 1800, , TS, 14.9N, 72.4W, 35, 1005,
20201101, 0000, , TS, 15.0N, 73.8W, 40, 1003,
20201101, 0600, , TS, 15.0N, 75.2W, 45, 999,
20201101, 1200, , TS, 14.9N, 76.7W, 50, 995,
20201101, 1800, , TS, 14.9N, 78.4W, 55, 992,
20201102, 0000, , HU, 14.9N, 79.4W, 65, 987,
20201102, 0600, , HU, 14.9N, 80.4W, 75, 980,
20201102, 1200, , HU, 14.8N, 81.1W, 95, 971,
20201102, 1800, , HU, 14.7N, 82.0W, 115, 948,
20201103, 0000, , HU, 14.3N, 82.5W, 130, 932,
20201103, 0600, , HU, 14.0N, 82.9W, 140, 919,
20201103, 1200, , HU, 13.6N, 83.1W, 130, 934,
20201103, 1800, , HU, 13.7N, 83.3W, 110, 947,
20201103, 2200, L, HU, 13.8N, 83.5W, 120, 941,
20201104, 0000, , HU, 13.8N, 83.7W, 100, 960,
20201104, 0600, , HU, 13.8N, 84.3W, 65, 979,
20201104, 1200, , TS, 13.8N, 84.9W, 45, 991,
20201104, 1800, , TS, 13.9N, 85.3W, 35, 997,
20201105, 0000, , TD, 14.1N, 86.0W, 30, 1003,
20201105, 0600, , TD, 14.7N, 86.7W, 30, 1004,
20201105, 1200, , TD, 15.1N, 87.3W, 25, 1005,
20201105, 1800, , DB, 15.5N, 87.7W, 25, 1005,
20201106, 0000, , DB, 16.2N, 87.8W, 25, 1005,
20201106, 0600, , DB, 16.7N, 87.6W, 30, 1004,
20201106, 1200, , DB, 17.0N, 87.4W, 30, 1004,
20201106, 1800, , LO, 17.2N, 87.1W, 30, 1004,
20201107, 0000, , TS, 17.5N, 86.5W, 35, 1001,
20201107, 0600, , TS, 18.2N, 85.5W, 40, 999,
20201107, 1200, , TS, 19.0N, 83.2W, 50, 996,
20201107, 1800, , TS, 19.8N, 81.3W, 55, 994,
20201108, 0000, , TS, 20.4N, 80.3W, 60, 991,
20201108, 0600, , TS, 21.1N, 79.5W, 60, 990,
20201108, 0900, L, TS, 21.6N, 79.2W, 60, 990,
20201108, 1200, , TS, 22.1N, 79.0W, 55, 992,
20201108, 1800, , TS, 23.5N, 79.2W, 55, 993,
20201109, 0000, , TS, 24.5N, 80.1W, 60, 991,
20201109, 0330, L, TS, 24.8N, 80.7W, 60, 991,
20201109, 0600, , TS, 25.0N, 81.4W, 60, 991,
20201109, 1200, , TS, 24.8N, 82.9W, 55, 992,
20201109, 1800, , TS, 24.2N, 84.1W, 45, 996,
20201110, 0000, , TS, 23.5N, 84.9W, 45, 997,
20201110, 0600, , TS, 23.0N, 85.4W, 45, 995,
20201110, 1200, , TS, 22.6N, 85.4W, 50, 992,
20201110, 1800, , TS, 22.9N, 85.1W, 55, 990,
20201111, 0000, , TS, 23.5N, 84.7W, 60, 988,
20201111, 0600, , HU, 24.5N, 84.2W, 65, 985,
20201111, 0900, R, HU, 25.1N, 84.0W, 70, 983,
20201111, 1200, , HU, 25.7N, 83.9W, 65, 986,
20201111, 1800, , TS, 26.9N, 83.7W, 55, 990,
20201112, 0000, , TS, 27.9N, 83.5W, 50, 992,
20201112, 0600, , TS, 28.6N, 83.3W, 45, 994,
20201112, 0900, L, TS, 29.1N, 83.0W, 45, 995,
20201112, 1200, , TS, 29.8N, 82.4W, 40, 999,
20201112, 1800, , TS, 31.2N, 81.3W, 40, 1000,
20201113, 0000, , TS, 32.0N, 79.9W, 40, 1001,
Some key thoughts:
* Genesis is moved up 6 hours, largely because they were holding due to uncertainty with ASCAT passes missing.
* The intensities between genesis and the first Recon flight were increased as the aircraft already found a strong tropical storm.
* As for the peak intensity, that is a difficult one to assess. After going back through the data, I settled on
140 kt, although it was a tossup between 135 and 140. Initially I went with 135 but going back into the fixes gives me enough confidence to go 140. Some key points:
** The highest flight-level winds were 138 kt, which translates to 122 kt.
** The highest SFMR reading was 135 kt, which was likely legitimate even though there are some issues with the SFMR at the high end.
** The lowest Recon pressure was 923 mb at 0330Z. That would translate to about 135 kt using pressure-wind relationships.
** Satellite signatures, even adjusted for the eye temperature, would support at least 140-145 kt.
** Finally, it appears that Eta peaked at 06Z once the aircraft left, and the sampling was limited as well. Using that assumption, satellite estimates, the poor sampling and the SFMR, the peak intensity was derived. My estimate for the lowest pressure was
919 mb with the same theories.
* After peak intensity, the trajectory is adjusted. Instead, I believe Eta rapidly weakened - as fast as it strengthened - up to 1800Z, dropping to 110 kt. However, given satellite improvements, I believe it re-strengthened in the last few hours leading to landfall. The landfall intensity of
120 kt is unchanged.
* The track is indeed broken with a wave/low phase. It was inconclusive whether an LLC existed on November 5-6 and I believe the circulation dissipated at 18Z November 5. A low reformed around 18Z November 6 and re-genesis followed six hours later. By then, it was already a tropical storm per ASCAT.
* The intensity in the NW Caribbean is adjusted upwards pre-Recon, and also post-Recon to a peak of 60 kt. That is also my estimate for the intensity at Cuban landfall, based on surrounding Recon data.
* The intensity at Keys landfall is also increased to
60 kt. That is based on an SFMR reading of 58 kt, radar echoes translating to about 59 kt at the surface and flight-level winds of 68 kt.
* Intensities are smoothed out while Eta made the loop in the southern Gulf. However, its short-lived and abrupt re-intensification is also modified slightly. A peak of 70 kt is added at a non-synoptic time (09Z) as that was when radar and satellite looked best. By 12Z, it had already started to decay.
* Final landfall at Cedar Key has its intensity decreased slightly to
45 kt, based on slight weakening after Recon left.