Author Topic: Tropical Storm Hanna  (Read 27433 times)

Offline rdale

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Re: Tropical Storm Hanna
« Reply #40 on: 09/02/2008 09:47 pm »
Hanna slightly weakened during the day, and isn't expected to gain much (if any) strength over the next 24 hours.

Online Orbiter

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Re: Tropical Storm Hanna
« Reply #41 on: 09/02/2008 11:16 pm »
Hurricane season is really walloping the Space Shuttle launch schedule for STS-125.
KSC Engineer, astronomer, rocket photographer.

Offline RedSky

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Re: Tropical Storm Hanna
« Reply #42 on: 09/03/2008 12:35 am »
Here's a schematic of the potential wind swath (10m sustained 1-minute in mph) for Hanna which uses the NHC "wind radii" on the forecast advisories (the 5PM EDT 2 Sep Advisory):


Offline rdale

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Re: Tropical Storm Hanna
« Reply #43 on: 09/03/2008 12:42 am »
Unfortunately that uses NHC points, which are not necessarily valid. Strangely enough - she has weakened more and begun moving EAST this evening!

Offline MechTech

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Re: Tropical Storm Hanna
« Reply #44 on: 09/03/2008 01:15 am »
We jacked up the RSS on A today. Just let it down last week after jacking for Fay. Gets the drive wheels off the tracks so that wind loading can't damage the wheels.

Offline cd-slam

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Re: Hurricane Hanna
« Reply #45 on: 09/03/2008 05:08 am »
Quote from: LostInSpace link=xtopic=14164.msg311730#msg311730 date=1220364801
KSC is now at level 4 in prep for Hanna

Thanks. Is that the same as "HURCON IV"?

"72 hours prior to forecasted arrival of 50 knot / 58 mph sustained winds
Personnel report for normal duty as usual. HMT begins developing securing plans and final configurations required for all Shuttle facilities and hardware..."

I have a question about these "HURCON" conditions. It is stated as "x hours prior to forecasted arrival of 50 knot winds. But NHC will rarely, if ever, give 100% probability of winds at a fixed location, usually it is in graphical form of percentage. For example, when HURCON IV was declared for KSC, the NHC graphic showed a probability of 50 knot winds within 72 hours of about 20% at KSC.

Is there a "magic number" for these percentages or is a decision based solely on projected path and expected storm strength, rather than on wind speed probability data? 

Offline Jim

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Re: Tropical Storm Hanna
« Reply #46 on: 09/03/2008 08:34 am »
Just ignore the wind speed numbers.  "x hours prior to forecasted arrival of storm"

Offline rdale

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Re: Tropical Storm Hanna
« Reply #47 on: 09/03/2008 12:42 pm »
Hanna is BARELY a tropical storm right now... Pressure way up, winds way down. I'm shocked that NHC still has her becoming a hurricane, I just don't see that given her status this morning. Movement continues to the EAST.

Offline marshallsplace

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Re: Tropical Storm Hanna
« Reply #48 on: 09/03/2008 01:26 pm »
NASA PAO not sure whether Hanna or Ike, but nice shots anyway:

Offline psloss

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Re: Tropical Storm Hanna
« Reply #49 on: 09/03/2008 01:28 pm »
NASA PAO not sure whether Hanna or Ike, but nice shots anyway:
Ike.  Hanna has rarely had this kind of "presentation."

Offline shuttlefan

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Re: Tropical Storm Hanna
« Reply #50 on: 09/03/2008 02:41 pm »
Hanna is BARELY a tropical storm right now... Pressure way up, winds way down. I'm shocked that NHC still has her becoming a hurricane, I just don't see that given her status this morning. Movement continues to the EAST.

Perhaps if the storm keeps moving East that's a good sign for KSC and they MAY be able to roll earlier.

Offline psloss

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Re: Tropical Storm Hanna
« Reply #51 on: 09/03/2008 02:58 pm »
Perhaps if the storm keeps moving East that's a good sign for KSC and they MAY be able to roll earlier.
It's also possible that the current meandering of the storm just delays it from clearing the KSC area, which could extend the delay to the 125 rollout past Saturday.

Offline rdale

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Re: Tropical Storm Hanna
« Reply #52 on: 09/03/2008 03:04 pm »
Agreed - if they aren't rolling with a 10% chance of winds exceeding the criteria, they aren't going anywhere anytime soon. I disagree, but I'm just a weatherman ;)

Offline ChrisGebhardt

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Re: Tropical Storm Hanna
« Reply #53 on: 09/03/2008 03:07 pm »
11am report has Hanna finally moving North at 5mph.  New path attached. Threat cone has shifted further east.

Offline rdale

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Re: Tropical Storm Hanna
« Reply #54 on: 09/03/2008 03:26 pm »
It's not as much a northward motion yet - there's just no way to find a center (one doesn't exist really) so they are using what the computers said would happen to start off a path. No computer really ramps her up at all, NHC is just being conservative.

But at least we dropped to only a 10% chance of > 50kt winds!

Offline ChrisGebhardt

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Re: Tropical Storm Hanna
« Reply #55 on: 09/03/2008 03:36 pm »
It's not as much a northward motion yet - there's just no way to find a center (one doesn't exist really) so they are using what the computers said would happen to start off a path. No computer really ramps her up at all, NHC is just being conservative.

But at least we dropped to only a 10% chance of > 50kt winds!

Ah... thanks Rob. That's the information you don't hear on the news down here. ;)

Offline Antares

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Re: Hurricane Hanna
« Reply #56 on: 09/03/2008 03:58 pm »
I have a question about these "HURCON" conditions. It is stated as "x hours prior to forecasted arrival of 50 knot winds. But NHC will rarely, if ever, give 100% probability of winds at a fixed location, usually it is in graphical form of percentage. For example, when HURCON IV was declared for KSC, the NHC graphic showed a probability of 50 knot winds within 72 hours of about 20% at KSC.

Is there a "magic number" for these percentages or is a decision based solely on projected path and expected storm strength, rather than on wind speed probability data? 

These calls are made by Program management under advice of the Spaceflight Meteorology Group at JSC and the 45th Weather Squadron at Patrick.  They get a lot of their info from the NHC, but they paint with a finer brush and use their own products rather than just the NHC stuff.
If I like something on NSF, it's probably because I know it to be accurate.  Every once in a while, it's just something I agree with.  Facts generally receive the former.

Offline Chris Bergin

Re: Tropical Storm Hanna
« Reply #57 on: 09/03/2008 05:55 pm »
Hanna reducing her threat? We're hearing rollout is now Thursday 10am.
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Offline mike robel

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Re: Tropical Storm Hanna
« Reply #58 on: 09/03/2008 06:20 pm »
Florida appears to be outside the probablity cone at the present time and Hanna should be fairly far off shore if the current trend continues.

Offline rdale

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Re: Tropical Storm Hanna
« Reply #59 on: 09/03/2008 08:06 pm »
Hanna's central pressure has dropped just a bit per the last recon plane, but no changes in the big picture. All computer forecasts keep it well away from a KSC impact.

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