2005 Season Retrospective

[CrazyC83]

As far as other 2005 storms, my thoughts on the actual peak intensities:

Wilma - 170 kt / 878 mb

What's the reasoning on this one? Also do you have any thoughts on landfall intensities for other storms that year?

It was stated in the TCR that the pressure was still falling at the time of the 882 peak (based on the 0804Z drop of 884 w/ 23 kt wind), and that there was a good chance it continued to fall for a little while afterwards. Based on infrared satellite imagery (seen here), the peak likely occurred around 10-11z, as that’s when the -80C tops began to quickly warm which was consistent with an ERC that began likely setting in around that time, which was hinted at in the 11am advisory. The extrapolated pressure was 881 as noted, and given an additional two hours of deepening up until peak appearance before it began degrading, suggests an additional 2-3 mb drop, which would put Wilma’s peak at at 878 mb. A slight increase in winds is also plausible, hence the 170 kt estimate from Crazy, although I do have slight reservations with that considering Wilma was monsoonal in nature and consistently had a much lower pressure on average for much of its Caribbean lifetime - the most anomalous being 55 kt / 988 mb and 135 kt / 892 mb at 00z 10/18 and 00z 10/20 respectively. I personally have it a bit lower at 165 kt but 878 is still fine for the pressure.

As for other storms, some of the most significant changes and the reasoning:

Dennis 135 kt (up from 130) - FL winds of 150 actually supported that. I think they avoided going there because the pressure was high at 938 mb, but it's often high in smaller Caribbean storms.

Irene 85 kt (down from 90) - When Recon was in the plane, it was consistently below Dvorak. The thought is that the trend of that continued.

Nate 85 kt (up from 80) - Some T5.0 readings were given after Recon left, and Recon earlier was right on Dvorak.

Ophelia 80 kt (up from 75) - 91 kt FL winds at 700 mb (we've learned SFMR isn't reliable near shore).

Delta 65 kt (up from 60) - Ship report of 60 kt on weaker side combined with eye structure, plus 63 kt land reading after being post-tropical in Canary Islands.

Quite a few pressures were adjusted, since the KZC wasn't yet in real use. For example, Beta was kept at 100 kt (admittedly a bit generous) but the pressure I thought was 967 mb.

Landfalls would largely remain the same, with a few tweaks, with one exception: Rita was likely a category 2 at landfall based on radar and dropsonde data (95 kt) despite a pressure of 939 mb (based on Johnson's Bayou data).

[wwizard]

20 years ago today Katrina was born.

[Ptarmigan]

As far as other 2005 storms, my thoughts on the actual peak intensities:

Wilma - 170 kt / 878 mb

What's the reasoning on this one? Also do you have any thoughts on landfall intensities for other storms that year?

It was stated in the TCR that the pressure was still falling at the time of the 882 peak (based on the 0804Z drop of 884 w/ 23 kt wind), and that there was a good chance it continued to fall for a little while afterwards. Based on infrared satellite imagery (seen here), the peak likely occurred around 10-11z, as that’s when the -80C tops began to quickly warm which was consistent with an ERC that began likely setting in around that time, which was hinted at in the 11am advisory. The extrapolated pressure was 881 as noted, and given an additional two hours of deepening up until peak appearance before it began degrading, suggests an additional 2-3 mb drop, which would put Wilma’s peak at at 878 mb. A slight increase in winds is also plausible, hence the 170 kt estimate from Crazy, although I do have slight reservations with that considering Wilma was monsoonal in nature and consistently had a much lower pressure on average for much of its Caribbean lifetime - the most anomalous being 55 kt / 988 mb and 135 kt / 892 mb at 00z 10/18 and 00z 10/20 respectively. I personally have it a bit lower at 165 kt but 878 is still fine for the pressure.

I always found it strange that Wilma had 892 millibars and 135 knot winds. It would be more common in the West Pacific or Southwest Pacific Basin. I do believe Wilma had central pressure below 880 millibars. The winds had to be stronger than 160 knots.

[Ptarmigan]

One thought might be to reanalyze some of the storms. I've taken another look at Katrina, and here's what I would change. I'm not knowledgeable enough to adjust the size of the storms. Red - stronger, blue - new point, green - weaker.

AL122005, KATRINA, 34,
20050823, 1800, , TD, 23.1N, 75.1W, 30, 1008, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050824, 0000, , TS, 23.4N, 75.7W, 35, 1007, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050824, 0600, , TS, 23.8N, 76.2W, 35, 1005, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050824, 1200, , TS, 24.5N, 76.5W, 40, 1004, 60, 60, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050824, 1800, , TS, 25.4N, 76.9W, 45, 1001, 60, 60, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050825, 0000, , TS, 26.0N, 77.7W, 45, 1000, 60, 60, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050825, 0600, , TS, 26.1N, 78.4W, 50, 995, 60, 60, 0, 0, 15, 0, 0, 0, 0, 0, 0, 0, -999
20050825, 1200, , TS, 26.2N, 79.0W, 60, 990, 60, 60, 30, 50, 20, 20, 0, 0, 0, 0, 0, 0, -999
20050825, 1800, , HU, 26.2N, 79.6W, 65, 985, 70, 70, 50, 60, 25, 25, 20, 20, 0, 0, 0, 0, -999
20050825, 2230, L, HU, 26.0N, 80.1W, 70, 982, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, 15
20050826, 0000, , HU, 25.9N, 80.3W, 70, 983, 70, 70, 50, 40, 20, 20, 20, 20, 10, 10, 10, 10, -999
20050826, 0600, , HU, 25.4N, 81.3W, 65, 985, 75, 75, 40, 30, 60, 60, 20, 20, 10, 10, 10, 10, -999
20050826, 1200, , HU, 25.1N, 82.0W, 80, 974, 75, 75, 45, 25, 60, 60, 25, 20, 20, 20, 10, 10, -999
20050826, 1800, , HU, 24.9N, 82.6W, 90, 965, 75, 75, 55, 35, 60, 60, 35, 20, 20, 20, 15, 10, -999
20050827, 0000, , HU, 24.6N, 83.3W, 95, 956, 90, 75, 75, 75, 60, 60, 40, 30, 25, 25, 20, 15, -999
20050827, 0600, , HU, 24.4N, 84.0W, 100, 944, 130, 90, 90, 130, 60, 60, 45, 60, 35, 30, 30, 25, -999
20050827, 1200, , HU, 24.4N, 84.7W, 100, 940, 130, 90, 90, 130, 60, 60, 45, 60, 35, 30, 30, 25, -999
20050827, 1800, , HU, 24.5N, 85.3W, 95, 951, 140, 90, 90, 130, 70, 70, 60, 70, 45, 35, 35, 35, -999
20050828, 0000, , HU, 24.8N, 85.9W, 105, 939, 140, 100, 100, 140, 80, 80, 65, 80, 60, 45, 45, 50, -999
20050828, 0600, , HU, 25.2N, 86.7W, 130, 922, 160, 160, 125, 140, 100, 100, 75, 100, 75, 75, 50, 75, -999
20050828, 0900, R, HU, 25.4N, 87.2W, 140, 915, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999
20050828, 1200, , HU, 25.7N, 87.7W, 150, 909, 180, 180, 125, 140, 120, 120, 75, 100, 90, 90, 50, 75, -999
20050828, 1500, W, HU, 26.1N, 88.1W, 155, 905, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999
20050828, 1800, , HU, 26.3N, 88.6W, 150, 902, 200, 180, 125, 180, 120, 120, 75, 120, 90, 90, 50, 90, -999
20050829, 0000, , HU, 27.2N, 89.2W, 140, 904, 200, 200, 150, 180, 120, 120, 75, 100, 90, 90, 60, 80, -999
20050829, 0600, , HU, 28.2N, 89.6W, 120, 909, 200, 200, 150, 150, 120, 120, 75, 100, 90, 90, 60, 70, -999
20050829, 1110, L, HU, 29.3N, 89.6W, 105, 920, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, 20
20050829, 1200, , HU, 29.5N, 89.6W, 105, 922, 200, 200, 150, 100, 120, 120, 75, 75, 90, 90, 60, 60, -999
20050829, 1445, L, HU, 30.2N, 89.6W, 105, 925, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, 20
20050829, 1800, , HU, 31.1N, 89.6W, 85, 944, 100, 180, 100, 100, 75, 100, 75, 75, 50, 50, 30, 30, -999
20050830, 0000, , TS, 32.6N, 89.1W, 55, 961, 75, 90, 90, 50, 50, 60, 0, 0, 0, 0, 0, 0, -999
20050830, 0600, , TS, 34.1N, 88.6W, 40, 981, 75, 90, 75, 50, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050830, 1200, , TD, 35.6N, 88.0W, 30, 987, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050830, 1800, , TD, 37.0N, 87.0W, 30, 990, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050831, 0000, , TD, 38.6N, 85.3W, 30, 994, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050831, 0600, , TD, 40.1N, 82.9W, 25, 996, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999

A few highlights:

* Genesis is unchanged, but the other early intensities are increased and I think it became a tropical storm 12 hours earlier. The first Recon mission had low-level winds of 39 kt, while the second found 45 kt at 925 mb. That supports 35 kt at 00Z and 06Z. Radar data also suggested stronger intensities on the 25th.

* The landfall intensity in Florida is maintained at 70 kt. An intensity of 75 kt was considered due to sparse observations given the limited observations and data, however, that was inconclusive. The landfall pressure of 982 mb is based on slight weakening before it reached the NHC building which measured 983 mb. HURDAT and the TCR have a discrepancy as the TCR suggests that it weakened below hurricane strength when it left Florida, then quickly regained it - the TCR should have a point there for that. However, the analysis I have suggests that Katrina remained a hurricane all the way across, and departed with 65 kt winds.

* The first RI period is moved upwards based on Recon data. Katrina probably became a major hurricane a little earlier, I estimate 06Z on the 27th. After that, the ERC is more pronounced and a brief weakening is introduced, dropping to 95 kt at 18Z that day as winds were found to be a bit lower (alongside the rise in pressure from 940 mb to 951 mb). Re-intensification would follow afterward though, and the most memorable RI period early on the 28th sees increases.

* There was no Recon between about 0330Z on the 28th (935 mb and 137 kt FL winds) and about 0930Z that day (915 mb, next pass at 1100Z found 153 kt FL and the following pass at 1330Z found 166 kt FL winds). It is likely Katrina had reached category 5 intensity by about 08-09Z. The 06Z intensity is increased to reflect that. Added a BT point at 09Z as well.

* The peak intensity is increased to 155 kt, and happened earlier than in HURDAT - at 15Z. That is based on a combination of the 166 kt FL winds (which have been found to sometimes have a low bias when rapidly intensifying) and the T7.5 Dvorak rating, as there was no SFMR at the time. By the time of minimum pressure - 902 mb (just after 18Z), the winds were likely already decreasing, and a combination of flight level and SFMR readings suggested the weakening probably began a bit earlier.

* The dramatic structural changes were already underway at 00Z and the pressure-wind mismatch began. It was probably still a category 5 at 00Z, but not for much longer, despite an extremely low pressure. The weakening phase is largely unchanged.

* The landfall intensity of Katrina has long been controversial. Flight-level winds were 133 kt, which should support 120 kt. However, it was clear by then that a 90% estimate was no longer reflective of the true intensity, and 80% would support 106 kt. A dropsonde in the eyewall supported 100-105 kt. The SFMR measured 96 kt, although that isn't very accurate in shallow water. My estimate after learning of all data from 20 years of experience is that the landfall intensity was 105 kt. Most of that weakening likely occurred in the 00Z-09Z period, and the radar structure actually improved a bit before final landfall at 15Z in Mississippi. As a result, the intensity was likely still 105 kt at that time, same as estimated now. The landfall pressure of 920 mb is unchanged, based on a reading in the eye in Buras and aircraft readings of 918 and 922 mb around that time.

* After landfall, data was limited so I tried to smooth things out with the limited observations available. I also think it never became extratropical as there wasn't a clear frontal structure early on the 31st. It probably remained a tropical cyclone until 12Z, when it opened up into a trough and was eventually absorbed by another front over Canada.

This is all based on 20 years of learning and new knowledge I have.

When I look at satellite images of Katrina, I notice it got larger after it peaked. When Katrina headed towards Mississippi, it looks like it was trying to intensify again. The land interaction put a lid on it. I would not be surprised if the central pressure at Buras was 918 millibars. That normally supports a Category 5 hurricane, but Katrina was large at the time of landfall.

[CrazyC83]

One thought might be to reanalyze some of the storms. I've taken another look at Katrina, and here's what I would change. I'm not knowledgeable enough to adjust the size of the storms. Red - stronger, blue - new point, green - weaker.

AL122005, KATRINA, 34,
20050823, 1800, , TD, 23.1N, 75.1W, 30, 1008, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050824, 0000, , TS, 23.4N, 75.7W, 35, 1007, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050824, 0600, , TS, 23.8N, 76.2W, 35, 1005, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050824, 1200, , TS, 24.5N, 76.5W, 40, 1004, 60, 60, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050824, 1800, , TS, 25.4N, 76.9W, 45, 1001, 60, 60, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050825, 0000, , TS, 26.0N, 77.7W, 45, 1000, 60, 60, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050825, 0600, , TS, 26.1N, 78.4W, 50, 995, 60, 60, 0, 0, 15, 0, 0, 0, 0, 0, 0, 0, -999
20050825, 1200, , TS, 26.2N, 79.0W, 60, 990, 60, 60, 30, 50, 20, 20, 0, 0, 0, 0, 0, 0, -999
20050825, 1800, , HU, 26.2N, 79.6W, 65, 985, 70, 70, 50, 60, 25, 25, 20, 20, 0, 0, 0, 0, -999
20050825, 2230, L, HU, 26.0N, 80.1W, 70, 982, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, 15
20050826, 0000, , HU, 25.9N, 80.3W, 70, 983, 70, 70, 50, 40, 20, 20, 20, 20, 10, 10, 10, 10, -999
20050826, 0600, , HU, 25.4N, 81.3W, 65, 985, 75, 75, 40, 30, 60, 60, 20, 20, 10, 10, 10, 10, -999
20050826, 1200, , HU, 25.1N, 82.0W, 80, 974, 75, 75, 45, 25, 60, 60, 25, 20, 20, 20, 10, 10, -999
20050826, 1800, , HU, 24.9N, 82.6W, 90, 965, 75, 75, 55, 35, 60, 60, 35, 20, 20, 20, 15, 10, -999
20050827, 0000, , HU, 24.6N, 83.3W, 95, 956, 90, 75, 75, 75, 60, 60, 40, 30, 25, 25, 20, 15, -999
20050827, 0600, , HU, 24.4N, 84.0W, 100, 944, 130, 90, 90, 130, 60, 60, 45, 60, 35, 30, 30, 25, -999
20050827, 1200, , HU, 24.4N, 84.7W, 100, 940, 130, 90, 90, 130, 60, 60, 45, 60, 35, 30, 30, 25, -999
20050827, 1800, , HU, 24.5N, 85.3W, 95, 951, 140, 90, 90, 130, 70, 70, 60, 70, 45, 35, 35, 35, -999
20050828, 0000, , HU, 24.8N, 85.9W, 105, 939, 140, 100, 100, 140, 80, 80, 65, 80, 60, 45, 45, 50, -999
20050828, 0600, , HU, 25.2N, 86.7W, 130, 922, 160, 160, 125, 140, 100, 100, 75, 100, 75, 75, 50, 75, -999
20050828, 0900, R, HU, 25.4N, 87.2W, 140, 915, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999
20050828, 1200, , HU, 25.7N, 87.7W, 150, 909, 180, 180, 125, 140, 120, 120, 75, 100, 90, 90, 50, 75, -999
20050828, 1500, W, HU, 26.1N, 88.1W, 155, 905, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999
20050828, 1800, , HU, 26.3N, 88.6W, 150, 902, 200, 180, 125, 180, 120, 120, 75, 120, 90, 90, 50, 90, -999
20050829, 0000, , HU, 27.2N, 89.2W, 140, 904, 200, 200, 150, 180, 120, 120, 75, 100, 90, 90, 60, 80, -999
20050829, 0600, , HU, 28.2N, 89.6W, 120, 909, 200, 200, 150, 150, 120, 120, 75, 100, 90, 90, 60, 70, -999
20050829, 1110, L, HU, 29.3N, 89.6W, 105, 920, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, 20
20050829, 1200, , HU, 29.5N, 89.6W, 105, 922, 200, 200, 150, 100, 120, 120, 75, 75, 90, 90, 60, 60, -999
20050829, 1445, L, HU, 30.2N, 89.6W, 105, 925, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, -999, 20
20050829, 1800, , HU, 31.1N, 89.6W, 85, 944, 100, 180, 100, 100, 75, 100, 75, 75, 50, 50, 30, 30, -999
20050830, 0000, , TS, 32.6N, 89.1W, 55, 961, 75, 90, 90, 50, 50, 60, 0, 0, 0, 0, 0, 0, -999
20050830, 0600, , TS, 34.1N, 88.6W, 40, 981, 75, 90, 75, 50, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050830, 1200, , TD, 35.6N, 88.0W, 30, 987, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050830, 1800, , TD, 37.0N, 87.0W, 30, 990, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050831, 0000, , TD, 38.6N, 85.3W, 30, 994, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999
20050831, 0600, , TD, 40.1N, 82.9W, 25, 996, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -999

A few highlights:

* Genesis is unchanged, but the other early intensities are increased and I think it became a tropical storm 12 hours earlier. The first Recon mission had low-level winds of 39 kt, while the second found 45 kt at 925 mb. That supports 35 kt at 00Z and 06Z. Radar data also suggested stronger intensities on the 25th.

* The landfall intensity in Florida is maintained at 70 kt. An intensity of 75 kt was considered due to sparse observations given the limited observations and data, however, that was inconclusive. The landfall pressure of 982 mb is based on slight weakening before it reached the NHC building which measured 983 mb. HURDAT and the TCR have a discrepancy as the TCR suggests that it weakened below hurricane strength when it left Florida, then quickly regained it - the TCR should have a point there for that. However, the analysis I have suggests that Katrina remained a hurricane all the way across, and departed with 65 kt winds.

* The first RI period is moved upwards based on Recon data. Katrina probably became a major hurricane a little earlier, I estimate 06Z on the 27th. After that, the ERC is more pronounced and a brief weakening is introduced, dropping to 95 kt at 18Z that day as winds were found to be a bit lower (alongside the rise in pressure from 940 mb to 951 mb). Re-intensification would follow afterward though, and the most memorable RI period early on the 28th sees increases.

* There was no Recon between about 0330Z on the 28th (935 mb and 137 kt FL winds) and about 0930Z that day (915 mb, next pass at 1100Z found 153 kt FL and the following pass at 1330Z found 166 kt FL winds). It is likely Katrina had reached category 5 intensity by about 08-09Z. The 06Z intensity is increased to reflect that. Added a BT point at 09Z as well.

* The peak intensity is increased to 155 kt, and happened earlier than in HURDAT - at 15Z. That is based on a combination of the 166 kt FL winds (which have been found to sometimes have a low bias when rapidly intensifying) and the T7.5 Dvorak rating, as there was no SFMR at the time. By the time of minimum pressure - 902 mb (just after 18Z), the winds were likely already decreasing, and a combination of flight level and SFMR readings suggested the weakening probably began a bit earlier.

* The dramatic structural changes were already underway at 00Z and the pressure-wind mismatch began. It was probably still a category 5 at 00Z, but not for much longer, despite an extremely low pressure. The weakening phase is largely unchanged.

* The landfall intensity of Katrina has long been controversial. Flight-level winds were 133 kt, which should support 120 kt. However, it was clear by then that a 90% estimate was no longer reflective of the true intensity, and 80% would support 106 kt. A dropsonde in the eyewall supported 100-105 kt. The SFMR measured 96 kt, although that isn't very accurate in shallow water. My estimate after learning of all data from 20 years of experience is that the landfall intensity was 105 kt. Most of that weakening likely occurred in the 00Z-09Z period, and the radar structure actually improved a bit before final landfall at 15Z in Mississippi. As a result, the intensity was likely still 105 kt at that time, same as estimated now. The landfall pressure of 920 mb is unchanged, based on a reading in the eye in Buras and aircraft readings of 918 and 922 mb around that time.

* After landfall, data was limited so I tried to smooth things out with the limited observations available. I also think it never became extratropical as there wasn't a clear frontal structure early on the 31st. It probably remained a tropical cyclone until 12Z, when it opened up into a trough and was eventually absorbed by another front over Canada.

This is all based on 20 years of learning and new knowledge I have.

When I look at satellite images of Katrina, I notice it got larger after it peaked. When Katrina headed towards Mississippi, it looks like it was trying to intensify again. The land interaction put a lid on it. I would not be surprised if the central pressure at Buras was 918 millibars. That normally supports a Category 5 hurricane, but Katrina was large at the time of landfall.

It became extremely large after peak, almost like a storm in the NW Atlantic. Indeed, the satellite and radar presentation actually improved a bit between 11Z and 15Z. You could clearly see the dry air really come in around 05Z, dry up the west side in the next few hours, and then the west side rebuilt some around 12Z, even if the eye was a bit less defined due to land interaction. That re-analysis suggests no weakening between the two landfalls (although the pressure rose slightly). The big weakening looks to have been from 00Z to 09Z. There was very little land data available in Mississippi due to power outages and damaged equipment, and no pressure readings were recorded near that landfall. Slidell, to the west of the eye, measured 934 mb. I believe the last aircraft pass measured 928 mb with wind, but it might have been too high - hence the 925 mb estimate.

[NDG]

2005 will forever be a season to remember for many of us, hopefully it will be a long time before it repeats again.

Here is a little of my story of Katrina.

 https://x.com/NDGMETCHEF/status/1961794397646795241