A word from recon (and a mention about the 234kt dropsonde)

[senorpepr]

This was passed on to me...


Dear Folks,



Hello and thanks to everyone who has written with their concerns. I'm fine and my family in Florida is fine. After flying the storm Saturday night and Sunday morning our crew landed at Ellington Field in Houston. We hurrevac'd 15 of the 17 C-130s in our wing. Unfortunately, one of the planes left at Keesler was one of our brand new J model birds. They were changing a prop and never got it out in time. One of our pilots, Lt Colonel Doug Niolet, ended up stranded in Bay St Louis. He was one of the people described in CNN's "Stories of Survival" that rode out the storm on the second floor of a beachfront bed-and-breakfast on Highway 90 until the building collapsed then clung to a tree with seven others.



My car (parked at Keesler AFB in Biloxi) is somewhere on the coast, but in the big scheme of things....whatever happened to it has already happened and it is the least of my concerns now. Compared to some of my fellow-reservists, worrying about something like a vehicle seems very inconsequential. About half of the squadron lives in Mississippi. We are re-deploying from Houston up to Dobbins AFB in Atlanta on Wednesday. The Hurricane Hunters will probably operate out of Dobbins for the foreseeable future until the situation at Keesler is resolved.



It was certainly a memorable flight the other night. I have appended the controversial dropsonde message below. Whenever I can get ahold of the D file that has all the raw data, maybe James Franklin and Mike Black and other experts with the AVAPS system can take a look at it and determine how much of the 234 knot value coded at 866mb was real. I certainly believe the 181 knot reading at 882mb was valid, as well as the 185 knots at 868mb. The 166 knot mean boundary layer wind ending up matching exactly what we saw at flight level on that penetration of the northeast eyewall. The lowest 150 meter value of 158 knots shows the incredible force that stirred up the Gulf with such a fury that even the weakening trend at landfall was apparently too little too late to avoid a catastrophic surge once this energy reached the shallow waters of the Mississippi coast......Rich





UZNT13 KNHC 281436
XXAA 78147 99261 70879 08167 99919 26800 ///// 00/// ///// /////
92/// ///// ///// 85688 22001 10671 70371 14800 13621 88999 77999
31313 09608 81421
61616 AF302 1712A KATRINA OB 23
62626 EYEWALL 045 SPL 2621N08809W 1425 LST WND 063 MBL WND 07666
AEV 20507 DLM WND 11135 913707 WL150 06658 138 =
XXBB 78148 99261 70879 08167 00919 26800 11909 24600 22850 22001
33789 19803 44783 21401 55777 20602 66705 17000 77697 13600
21212 00919 ///// 11913 06657 22908 06161 33905 06657 44900 07158
55895 07665 66887 07661 77884 08179 88882 08181 99880 08680 11877
09168 22871 08673 33868 08685 44866 10734 55853 10174 66842 11167
77822 11684 88803 12155 99793 12167 11777 13117 22769 13114 33697
13620
31313 09608 81421
61616 AF302 1712A KATRINA OB 23
62626 EYEWALL 045 SPL 2621N08809W 1425 LST WND 063 MBL WND 07666
AEV 20507 DLM WND 11135 913707 WL150 06658 138


44866 10734 decodes to 866mb / 100° @ 234kt

[Stratosphere747]

A little confused here Senor...

Does that mean that they at least found a pressure of 882 AND 868?

[senorpepr]

A little confused here Senor...

Does that mean that they at least found a pressure of 882 AND 868?

No, those are levels in the atmosphere. As one raises in altitude, the pressure drops. Therefore, 882mb would be the level in high that 882mb would be measured. Considering at the time the surface pressure was 919mb and the 850mb height was 2,257ft... the suspect report of 234kt was found roughly at 2,100ft ASL.

[johngaltfla]

Thank you for that update and I'm very happy that you're ok. Thanks again for all of your great work here and in the air.

[Aquawind]

Cool Mike.. I remember we talked about that when it came out..
You won't catch me in a highrise during a hurricane..

Paul

[MKT2005]

What kind of implications does this have.

[senorpepr]

Thank you for that update and I'm very happy that you're ok. Thanks again for all of your great work here and in the air.

Thanks for your comments, but just to clarify... that message wasn't from me. It was from one of the crews working recon. I don't work with the recon squadron. I'm in an unrelated office hundreds of miles away.

[senorpepr]

What kind of implications does this have.

Well, it really doesn't mean too much for surface winds, although it could show that Katrina was getting ready to begin some massive cyclogenesis (strengthening). If you remember, a bit of dry air shot into Katrina prior to landfall. That coupled with the eyewall replacement cycle (ERC) earlier in the day allowed Katrina to weaken a bit prior to landfall. If this observation was true, it could indicate that had the dry air not have been introduced nor had Katrina made landfall, then after the ERC completed, Katrina could have been a very mean hurricane beyond words. Granted, the likelihood was limited, but had the rest of the levels near and below 866mb shown comparible winds... ouch.

[Matt-hurricanewatcher]

How strong do you think it peaked based on this.

[P.K.]

What kind of implications does this have.

Well, it really doesn't mean too much for surface winds, although it could show that Katrina was getting ready to begin some massive cyclogenesis (strengthening).

Could the winds really have increased this much over a pressure height of just 2hPa though? That would be some pressure gradient.

[inotherwords]

Thanks for posting that, senorpepr. I had the pleasure of interviewing one of the hurricane hunters a few years ago, Mike Black, for a story on their use of imaging technology and computers during storms. These guys are really a fantastic bunch, very brave and so nice and friendly and enthusiastic about what they do. I'm glad to hear they are all OK. I'd forgotten they're mostly out of Miss. as they also have a place in Miami they fly out of too.

[senorpepr]

What kind of implications does this have.

Well, it really doesn't mean too much for surface winds, although it could show that Katrina was getting ready to begin some massive cyclogenesis (strengthening).

Could the winds really have increased this much over a pressure height of just 2hPa though? That would be some pressure gradient.

Most likely it was a gust and some error combined... but if there was no error... then this gust could have been a sign for additional expansion of those winds.

[senorpepr]

Here is the decoded observation.

(I finally had the chance today to upgrade my decoder to accept non-standard level winds)

Dropsonde Observation
Storm Name: KATRINA (12L)
Mission Number: 17
Flight ID: AF302
Observation Number: 23
Time: 1400Z
Latitude: 26.1°N
Longitude: 87.9°W
Location: 252 mi SSE of Grand Isle, Louisana
Surface: 919 mb; Temp: 80°F; Dewpt: 26.8°F; N (N/A°) @ N/A mph
850mb height: 2257 ft; Temp: 72°F; Dewpt: 21.9°F; ESE (105°) @ 197 mph
700mb height: 11060 ft; Temp: 59°F; Dewpt: 14.8°F; SE (135°) @ 139 mph
EYEWALL 045 SPL 2621N08809W 1425 LST WND 063 MBL WND 07666
AEV 20507 DLM WND 11135 913707 WL150 06658 138 =
919mb winds: N (N/A°) @ N/A mph
913mb winds: ENE (65°) @ 181 mph
908mb winds: ENE (60°) @ 185 mph
905mb winds: ENE (65°) @ 181 mph
900mb winds: ENE (70°) @ 182 mph
895mb winds: ENE (75°) @ 190 mph
887mb winds: ENE (75°) @ 185 mph
884mb winds: E (80°) @ 206 mph
882mb winds: E (80°) @ 209 mph
880mb winds: E (85°) @ 207 mph
877mb winds: E (90°) @ 194 mph
871mb winds: E (85°) @ 199 mph
868mb winds: E (85°) @ 213 mph
866mb winds: ESE (105°) @ 270 mph
853mb winds: E (100°) @ 200 mph
842mb winds: ESE (110°) @ 192 mph
822mb winds: ESE (115°) @ 212 mph
803mb winds: ESE (120°) @ 179 mph
793mb winds: ESE (120°) @ 192 mph
777mb winds: SE (130°) @ 135 mph
769mb winds: SE (130°) @ 131 mph
697mb winds: SE (135°) @ 138 mph

[curtinnc]

Even still, at 2000 feet in height.. 270MPH winds... man this thing wasnot only trying to change the record books, but change the laws of physics too!

[curtinnc]

Here is the decoded observation.

(I finally had the chance today to upgrade my decoder to accept non-standard level winds)

Dropsonde Observation
Storm Name: KATRINA (12L)
Mission Number: 17
Flight ID: AF302
Observation Number: 23
Time: 1400Z
Latitude: 26.1°N
Longitude: 87.9°W
Location: 252 mi SSE of Grand Isle, Louisana
Surface: 919 mb; Temp: 80°F; Dewpt: 26.8°F; N (N/A°) @ N/A mph
850mb height: 2257 ft; Temp: 72°F; Dewpt: 21.9°F; ESE (105°) @ 197 mph
700mb height: 11060 ft; Temp: 59°F; Dewpt: 14.8°F; SE (135°) @ 139 mph
EYEWALL 045 SPL 2621N08809W 1425 LST WND 063 MBL WND 07666
AEV 20507 DLM WND 11135 913707 WL150 06658 138 =
919mb winds: N (N/A°) @ N/A mph
913mb winds: ENE (65°) @ 181 mph
908mb winds: ENE (60°) @ 185 mph
905mb winds: ENE (65°) @ 181 mph
900mb winds: ENE (70°) @ 182 mph
895mb winds: ENE (75°) @ 190 mph
887mb winds: ENE (75°) @ 185 mph
884mb winds: E (80°) @ 206 mph
882mb winds: E (80°) @ 209 mph
880mb winds: E (85°) @ 207 mph
877mb winds: E (90°) @ 194 mph
871mb winds: E (85°) @ 199 mph
868mb winds: E (85°) @ 213 mph
866mb winds: ESE (105°) @ 270 mph
853mb winds: E (100°) @ 200 mph
842mb winds: ESE (110°) @ 192 mph
822mb winds: ESE (115°) @ 212 mph
803mb winds: ESE (120°) @ 179 mph
793mb winds: ESE (120°) @ 192 mph
777mb winds: SE (130°) @ 135 mph
769mb winds: SE (130°) @ 131 mph
697mb winds: SE (135°) @ 138 mph

[johngaltfla]

Here is the decoded observation.

(I finally had the chance today to upgrade my decoder to accept non-standard level winds)

Dropsonde Observation
Storm Name: KATRINA (12L)
Mission Number: 17
Flight ID: AF302
Observation Number: 23
Time: 1400Z
Latitude: 26.1°N
Longitude: 87.9°W
Location: 252 mi SSE of Grand Isle, Louisana
Surface: 919 mb; Temp: 80°F; Dewpt: 26.8°F; N (N/A°) @ N/A mph
850mb height: 2257 ft; Temp: 72°F; Dewpt: 21.9°F; ESE (105°) @ 197 mph
700mb height: 11060 ft; Temp: 59°F; Dewpt: 14.8°F; SE (135°) @ 139 mph
EYEWALL 045 SPL 2621N08809W 1425 LST WND 063 MBL WND 07666
AEV 20507 DLM WND 11135 913707 WL150 06658 138 =
919mb winds: N (N/A°) @ N/A mph
913mb winds: ENE (65°) @ 181 mph
908mb winds: ENE (60°) @ 185 mph
905mb winds: ENE (65°) @ 181 mph
900mb winds: ENE (70°) @ 182 mph
895mb winds: ENE (75°) @ 190 mph
887mb winds: ENE (75°) @ 185 mph
884mb winds: E (80°) @ 206 mph
882mb winds: E (80°) @ 209 mph
880mb winds: E (85°) @ 207 mph
877mb winds: E (90°) @ 194 mph
871mb winds: E (85°) @ 199 mph
868mb winds: E (85°) @ 213 mph
866mb winds: ESE (105°) @ 270 mph
853mb winds: E (100°) @ 200 mph
842mb winds: ESE (110°) @ 192 mph
822mb winds: ESE (115°) @ 212 mph
803mb winds: ESE (120°) @ 179 mph
793mb winds: ESE (120°) @ 192 mph
777mb winds: SE (130°) @ 135 mph
769mb winds: SE (130°) @ 131 mph
697mb winds: SE (135°) @ 138 mph

2 7 0 ?

[NastyCat4]

This storm was definitely NOT a Cat 4. This will be like Andrew--reclassified, when accurate data comes out.

[truballer#1]

imagine if it hit land at 270mph winds!

[scostorms]

*Note to self* Stay off mountain peaks during hurricanes!

[senorpepr]

*Note to self* Stay off mountain peaks during hurricanes!

This is exactly a reason why they say vertical evacuations aren't a bright idea. Going inland is much better than going up.