[From the diaries by susanhu. I never got past Algebra I but I’ll take these numbers on the blind faith so popular these days! Seriously, this is impressive, and quite interesting, work by MilongaMan!]
Update [2005-9-22 2:35:13 by MilongaMan]:2: Latest recon gives max wind speed at 700mb of 170 knots, equivalent to 172-178 mph surface wind speed.
Update [2005-9-21 17:23:30 by MilongaMan]: Latest recon gives max wind speed at 700mb of 161 knots, equivalent to 163-168 mph surface wind speed. See this. Check the Vortex Message (Latest From the Eye) link from this page
Here is some info for those who like to get as close to the raw data as possible and calculate their own maximum sustained surface wind speed projections. Keep reading:
The Recon flights that measure different parameters inside a hurricane are either NOAA flights or AF flights. I found the raw flight data on Rita at the website of the 53rd Weather Reconnaissance Squadron.
The latest flight is at Supplementary Vortex (Storm Wind Profile) (Also see item F on The Latest From The Eye.)
The explanation of what the numbers are is here.
Jump below the fold to see in part what the report reads, with explanations, and to learn how the surface wind speed is calculated from the data:
038 URNT14 KNHC 211834
Report number, sent to NHC, on Sep 21 at 18:34 GMT (11:34am PDT or 2:34pm EDT)
SUPPLEMENTARY VORTEX DATA MESSAGE
INBOUND
LAT LON jHHH TTDD ddfff
01256 10878 13121 11007 04043
02254 20876 23076 21007 04053
03253 30874 33071 31008 04052
04251 40872 43054 40707 03052
05249 50870 53020 51008 04062
06247 60868 63002 61010 03064
07246 70866 73952 71010 04067
08244 80864 83813 81212 03102
The aircraft made 8 passes, inbound, each approximately 15 nm apart, until it reached the center of the hurricane, then 7 more passes from the center out (see the raw report; not excerpted here).
The height is at 700 millibars (j=3 in jHHH numbers above).
MF243 M0863 MF153
This is a maximum sustained wind reading of 153 knots. Multiply by 1.1515 to get around 176 mph.
AF300 1418A RITA OB 08
AF means this mission was flown by the Air Force Reserve
300 is the aircraft number (tail number 50300)
1418A means this was the 14th mission for this tropical system, and this was the 18th tropical cyclone of the season in the Atlantic
RITA was the name of the storm
OB 08 means this was the 8th observation from this mission
Here’s how to estimate surface wind speed from the 700mb reading of 176 mph. On this NHC page you will find that the current estimate, for the 700mb to surface extrapolation, is to multiply the reading by 0.88-0.91 (eyewall); typically by 0.91.
In this case this gives 155-160 mph, which is in the CAT 5 range (>=155 mph). Update [2005-9-21 19:22:4 by MilongaMan]:: This was subsequently revised to 161 knots, equivalent to 163-168 mph at the surface.
In general the formula would be:
W_surf_max_lower_bound = W_700mb_max * (1.1515 * 0.88) = W_700mb_max * 1.01332
W_surf_max_upper_bound = W_700mb_max * (1.1515 * 0.91) = W_700mb_max * 1.04786
where W_700mb_max is in knots, coming from aircraft recon missions, and W_surf_max is in miles per hour.
The flight recon schedule (both NOAA and AF) is at this NHC page. Also see here for other days and more links.
Hope this helps, and please let me know if you find errors.
[cross-posted on Dkos]
The ones I saw on TV were 914, saw 908 somewhere, but here appears to have more advanced and up to date information.
Thank you for your cooperation, and to show my appreciation in advance, here is a snippet from an Iqbal poem suitable for the occasion
I am not sure what your question is, but if you are talking about the minimum pressure in Rita, currently it is at 904mb (see Vortex Message (Latest From the Eye) (do shift+reload to purge the cached copy if there is one).
My right brain tells me that is very bad.
Someone with a left brain will be able to explain why.
What does that level of pressure signify in terms of how it will affect people on the ground, the cities, resorts, etc. Oh yeah, and those oil facilities too.
My understanding is that the lower the pressure, the greater the storm surge, but I bet MilongaMan has a better answer than that.
BTW, this is a really cool diary, MM!
BTW, this is a really cool diary, MM
Thank you! You are very kind!
<blush> 🙂
I think it is mostly an indication of the intensity of the cyclone (hurricane). The horizontal pressure difference induces winds, and they are stronger if the pressure difference is larger over a smaller area (the pressure gradient is large). So a [rapid] drop of the lowest pressure in Rita indicates the hurricane is strengthening, so the wind speeds might increase and be huricane-forced over a larger surface area than previously. I think we see this happenning already.
I don;t think low pressure per se would not do anything to the structures – just as the same pressure if you are at a height of say 2000 metres (6000 feet) does not damage people or machinery. It is the generated winds (and subsequently the waves/storm surge) that would do the most damage.
It’s more than that; the pressure tells you how much the local sea level changes as the storm passes through.
If you measure the atmospheric pressure in inches of mercury (with a barometer) you’re essentially measuring how heavy the air is above you. Rita, a particularly strong storm, has shown a pressure of 904 millibars, or 26.7 inches of mercury. Normal pressure at sea level is about 29.9 inches of mercury, so the mercury in your barometer has dropped about 3.2 inches.
But mercury is 13 times heavier than water, so that means that the sea water has risen, due only to the reduction in atmospheric pressure, by about 41.6 inches! This is contribution to the storm surge caused by the low air pressure of the storm.
And that doesn’t take into account the wind-driven surge, which is even bigger.
Yes, thanks for adding this. It is true that if you look at a static pressure difference between the eye and somewhere outside the hurricane, for a difference of 100 mb this would roughly correspond to a difference of 1 metre (3 feet or so) in sea level. This is not a discrete jump, though, but distributed over some distance, and I think it would typically be dwarfed by the storm surge, especially on shore, due to the winds (remember Katrina and the 15-20 foot surges, etc.).
Interesting line from your poem: “Your civilization will commit suicide
with its own daggers.”
For fun google haarpicane, you may find something like this.
http://portland.indymedia.org/en/2005/09/325038.shtml
“Impeach this month-long vacationing, negligent, treasonous, psychopathic “fiddling while Rome burns” twit.” Sounds reasonable.
Interesting: “They’re trying to say that greater federal authority would have made a difference,” said George Haddow, a former FEMA deputy chief of staff… “The reality is that the feds are the ones that screwed up in the first place.”
Bush has already allowed international armed troops (Dutch, Mexican, Canadian) to “police” the areas of the South. Wake up dummies. Wake up.” Ever wonder why foreign troopps are on our shores? Ever wonder why they are closing our bases, yet opening others around the World??
A bit more from the article: “OPERATION KATRINA is:
There is plenty more. Take this gentleman’s comments with what is happening, connect the dots.
Since I am ranting on Haarp, I figured what the hell… Google Haarp and Air Force…
Got this for one: U.S. Air Force Linked to Electronic Warfare Attack in Tennessee
By Alfred Webre, EcoNews Service (Vancouver, BC)
http://www.ecologynews.com/cuenews31.html
“It has now known that an official U.S. Air Force cheque was used to pay for the clandestine installation of massive telephone switching equipment at a defunct Tennessee Valley Authority nuclear power plant about five miles from the target media outlets. “
Strangely communications ended in New Orleans.
Read more of the article if you dare.
There were reports of the same type of activity when Wellstone’s plane crashed.
EtJ, You might be interested in knowing the following; I linked to the cuenews site above. The went to file, send link, so I could send the link to another identity.
There was a very long delay… an error message came up, eventually OE completed the sending process. I’ve not had this happen for several weeks. I do have a suspicion that it is connected to the subject line, which I did not change. I am operating on CableOne.net.
I have had suspicions on this before, and had been waiting to see what topic this system got “hung up on” next.
I would highly recommend changing subject lines to words more likely to avoid attracting any undue interest.
“Doesn’t sound so bad, but HAARP opponents say the Air Force isn’t telling the whole story. Their main beefs: first, the project will pour more energy into the sky than ever previously attempted, with who knows what awful consequences. Proponents say the energy isn’t that much greater than what existing ionospheric research facilities pump out and in any case is trivial compared to natural forces.
The second complaint is that the military wants to use HAARP to develop scary futuristic weapons. Among them: (1) a “global shield” that would zap the guidance systems of incoming ballistic missiles; (2) mind-control beams to incapacitate enemy troops, and (3) weather-control machines.
Sounds wild, but at least some of these schemes were embodied in technology patented in the 1980s by physicist Bernard Eastlund, who was a founder of a predecessor company of the current HAARP contractor. HAARP spokesmen say there’s no connection between Eastlund’s plans and theirs, and that they’re not cooking up death rays or anything of the sort.”
Do note WEATHER CONTROL……
Interesting wrap up to the article: “But check out both sides of the story and decide for yourself. For the full paranoid treatment see Angels Don’t Play This HAARP: Advances in Tesla Technology by Nick Begich, Earthpulse Press, PO Box 201393, Anchorage, Alaska 99520, 907-249-9111. For the Air Force’s version (complete with photos), check out the HAARP Website at http://server5550.itd.nrl.navy.mil/projects/haarp/haarpindex.html.”
http://www.straightdope.com/classics/a960308.html
An author that respects both sides of the story
CNN just reported that the low in the eye right now is 898 millibars and it is supposed to continue to strengthen. As is right now it is the third strongest hurricane on record. Ummmm, would somebody please stop testifying to Congress that global warming has nothing to do with this shit!
I just heard that too — the fact is that even if it weakens, it is still going to hit land like a motherfucker on wheels — I just went out earlier and got ice and water and batteries and flashlights….
Damn.
Yep, it is from the NHC site, but I can’t figure out where the data came from. Since it is not from the Air Force craft, it must be from NOAA aircraft dropping pressure sondes or some other source.
aircraft dropping a sonde – the links above in the diary just got updated with the latest readings.
When will it hit Houston? A close friend lives there who I’ve been encouraging to evacuate. Originally she was going to ride it out but emailed me this morning that she will leave tomorrow afternoon. I think she should leave now but what do I know?
and she needs to get ready to get the hell out if Houston is going to get hit! It ain’t a bull and it ain’t going to be an 8 second ride!
and counting……and this storm is stronger right now and doesn’t have much reason weaken. I think most people in the know would predict that it is going to hit harder than Katrina did. Not worth it, she has time to pack up her “can’t live withouts” and get herself to a safe distance!
60 hours? I think if she leaves tomorrow afternoon she should be ok. I heard that it would hit land Sat am but that might be when they eye lands.
sure. I do hope your friend is planning on leaving today. The warnings about this hurricane are getting more and more dire as time goes on. Third strongest on record…
I’m very concerned. She tried twice this morning but couldn’t get onto the highway…too packed. Had to turn around. She’s going to try again this afternoon or evening but may have to ride it out at home and is very scared…as I am for her. Pray for the people of Houston.
Any word on your friend? I hope she is on her way out. Sounds like a lot of people were having problem. They finally opened all of the roads one way and brought in more fuel, so hopefully people trying to get out won’t have a problem.
Some reports from Weatherunderground that Rita may stall. Hope this doesn’t happen:
http://www.weatherunderground.com/blog/JeffMasters/show.html
and spins itself out, that would be good.
That’s official.
Rita is now the 3rd strongest Atlantic hurricane on record with a CP of 898 mb, surpassing Katrina’s lowest recorded CP of 902 mb. She is growing in size as well, with 165 mph winds extending 70 miles outward from the eye. Rita now has the potential to be extraordinarily devastasting — the lowest central pressure ever recorded is 882 mb, a mark that Rita could well challenge. Do not take any chances with this storm. If you have even the slightest thought about evacuating, listen to it and stay safe.
Check also NOAA.
The warm Gulf of Mexico works like a hurricane machine. From now on, whenever a tropical storm or a weak hurricane enters the Gulf, and is going to a few day hike across, we have to say “Oops, he it goes again…” and hope for a lucky trajectory or lucky wind sheers.