Author Topic: STS-135 Launch Weather Thread  (Read 62450 times)

Offline jbirdav8r

  • Member
  • Posts: 22
  • Liked: 10
  • Likes Given: 0
Re: STS-135 Launch Weather Thread
« Reply #40 on: 07/06/2011 01:21 AM »
Hang on - while everyone's talking about weather from the LCC perspective, what's the take on visibility (cloud base+ceiling) for the millions of people who're going to be around the launch pad?

It's impossible to predict cloud locations 3 days away... There is an attempt by USAF & SMG already posted a bit back though if you want.

Yup - any word on haze? I read Visibility of 7 miles...which just puts causeway near the edge...

In aviation, forecast visibility is always expressed as "better than six statute miles."  It'll likely be better than that.

Offline STS-134

  • Member
  • Posts: 38
  • Liked: 0
  • Likes Given: 0
Re: STS-135 Launch Weather Thread
« Reply #41 on: 07/06/2011 01:35 AM »
Yup - any word on haze? I read Visibility of 7 miles...which just puts causeway near the edge...

In aviation, forecast visibility is always expressed as "better than six statute miles."  It'll likely be better than that.

What would you prefer?  No haze, but the Shuttle disappears into the clouds 20-25 seconds after launch (like happened on STS-134), or 7-10 miles visibility through haze but otherwise clear skies at the time of launch?

I would guess that, as the Shuttle ascends, it would get easier to see for people especially in the northern areas (Titusville, etc.) because you aren't looking through as much humidity?  Most of the really humid, hazy air is in the lowest 2 miles of the atmosphere, correct?

Offline Andrewwski

  • Parrothead
  • Full Member
  • ****
  • Posts: 1533
  • Buffalo, NY
  • Liked: 5
  • Likes Given: 0
Re: STS-135 Launch Weather Thread
« Reply #42 on: 07/06/2011 01:50 AM »
Yup - any word on haze? I read Visibility of 7 miles...which just puts causeway near the edge...

In aviation, forecast visibility is always expressed as "better than six statute miles."  It'll likely be better than that.

What would you prefer?  No haze, but the Shuttle disappears into the clouds 20-25 seconds after launch (like happened on STS-134), or 7-10 miles visibility through haze but otherwise clear skies at the time of launch?

I would guess that, as the Shuttle ascends, it would get easier to see for people especially in the northern areas (Titusville, etc.) because you aren't looking through as much humidity?  Most of the really humid, hazy air is in the lowest 2 miles of the atmosphere, correct?

Yep.  STS-118 was a hazy day.  I was in Titusville and the view of the pad was a bit blurred by haze.  But by the time Endeavour was a few degrees high, it was much, much clearer.
NEW MUSIC VIDEO:
STS-125 DREAMS in HD!

Offline wingsofdana

  • Member
  • Posts: 5
  • Liked: 0
  • Likes Given: 0
Re: STS-135 Launch Weather Thread
« Reply #43 on: 07/06/2011 02:53 AM »
My hubby is currently working a TAL site in Spain......my concern is more selfish than anything. When will the most accurate forecast be available? And how high is the probabilities of a Saturday or Sunday launch?

Offline rdale

  • Assistant to the Chief Meteorologist
  • Senior Member
  • *****
  • Posts: 9892
  • Lansing MI
  • Liked: 236
  • Likes Given: 21
Re: STS-135 Launch Weather Thread
« Reply #44 on: 07/06/2011 02:54 AM »
When will the most accurate forecast be available?

The "most" accurate? About 1 second before launch.

Quote
And how high is the probabilities of a Saturday or Sunday launch?

Already noted in the official forecast at http://forum.nasaspaceflight.com/index.php?topic=25812.0.
« Last Edit: 07/06/2011 02:55 AM by rdale »

Offline wingsofdana

  • Member
  • Posts: 5
  • Liked: 0
  • Likes Given: 0
Re: STS-135 Launch Weather Thread
« Reply #45 on: 07/06/2011 02:56 AM »
Thank you for your response. I was hoping for something more.....but, ok. I am seeing that most of the storms occurring in the area will be after the noon hour....hoping it holds true. Still alot of time left for the sea breezes to reposition as well. Fingers crossed for a Friday launch!

Offline rdale

  • Assistant to the Chief Meteorologist
  • Senior Member
  • *****
  • Posts: 9892
  • Lansing MI
  • Liked: 236
  • Likes Given: 21
Re: STS-135 Launch Weather Thread
« Reply #46 on: 07/06/2011 03:00 AM »
I appreciate your excitement about the forecast but there's only so much that can be done in the real world. You are asking someone to predict the location of a possible thunderstorm 60+ hours away. That's physically impossible. At this time odds are against a Friday launch.

Offline wingsofdana

  • Member
  • Posts: 5
  • Liked: 0
  • Likes Given: 0
Re: STS-135 Launch Weather Thread
« Reply #47 on: 07/06/2011 03:20 AM »
How about this one..........What is the probability of wind shear tearing the tropical wave apart?

Offline rdale

  • Assistant to the Chief Meteorologist
  • Senior Member
  • *****
  • Posts: 9892
  • Lansing MI
  • Liked: 236
  • Likes Given: 21
Re: STS-135 Launch Weather Thread
« Reply #48 on: 07/06/2011 03:26 AM »
I hate to seem negative - but I'm not quite sure what you are asking. There is a 20-40% chance of launching on Friday. That covers all possible weather outcomes at this point.

Offline STS-134

  • Member
  • Posts: 38
  • Liked: 0
  • Likes Given: 0
Re: STS-135 Launch Weather Thread
« Reply #49 on: 07/06/2011 03:27 AM »
How about this one..........What is the probability of wind shear tearing the tropical wave apart?
I doubt that would ever happen.  Wind shear simply prevents waves from developing further (into cyclones, for example), or weakens cyclones back into tropical depressions and tropical waves, but wind shear normally isn't enough to suppress the wave itself.  And unfortunately for Shuttle launches, it doesn't take organized cyclone activity to cause a scrub.
« Last Edit: 07/06/2011 03:28 AM by STS-134 »

Offline mixologist07

  • Member
  • Posts: 65
  • St. Louis
  • Liked: 0
  • Likes Given: 0
Re: STS-135 Launch Weather Thread
« Reply #50 on: 07/06/2011 03:32 AM »
The thing to remember:  20-40% of acceptable weather Friday.  You never know what may happen.  This is one of those times of the year where the weather pattern changes frequently and can really surprise you.  It makes it hard to predict this far out. 

Hang on and remember that there's nothing that anyone, even top-notch forecasters like Mr. Dale, can do to get a 100% accurate picture until we're right up on top of it and the systems and movement of the day can be predicted based on realtime data.


Offline Captain Kirk

  • Ad Astra
  • Member
  • Posts: 61
  • Harrisburg, PA
  • Liked: 0
  • Likes Given: 0
Re: STS-135 Launch Weather Thread
« Reply #51 on: 07/06/2011 04:14 AM »
The thing to remember:  20-40% of acceptable weather Friday.  You never know what may happen.  This is one of those times of the year where the weather pattern changes frequently and can really surprise you.  It makes it hard to predict this far out. 

Hang on and remember that there's nothing that anyone, even top-notch forecasters like Mr. Dale, can do to get a 100% accurate picture until we're right up on top of it and the systems and movement of the day can be predicted based on realtime data.

Agreed!  But I am amazed at the high accuracy of the predictions on weather in the 24 - 36 hour time frame, even in places like Florida.  Forecasters like Mr. Dale do a great job - and many times - a thankless job, too. 

We still love and respect you, rdale, whether its "go!" or "no-go" on Friday.
"Well, as you can see, we have another problem."
 - James T. Kirk, Captain, USS Enterprise

Offline LendMeYourYears

  • Member
  • Posts: 23
  • AJA
  • Royal Leamington Spa / University of Warwick, England
    • Twitter
  • Liked: 0
  • Likes Given: 0
Re: STS-135 Launch Weather Thread
« Reply #52 on: 07/06/2011 10:52 AM »
Just to get a mathematical statistical angle on this

@rdale : Don't expect you to know this off the bat - but I guess you could guess. What's the maximum sigma variation that you guys have had thus far between the 48-72 hour forecast, and actual weather? I'm not making a judgement on the models, but would just like to have a rough idea of the error bars (on whichever parameter)

(Btw: Just learnt this from talking to someone from Tessella at the UK Space conference yesterday - Mars atmospheric models for the Beagle-2 were off by about 4 sigma - led to real problems in EDL parachute deployment.

Oh..He also told me that bankers claim that the financial crisis of not so long ago was described as a 27 sigma event. Now I leave it to you to judge the economists gamblers, if they know what they're doing, if they even HAVE a VAGUE model:P)

(Sigma btw - is standard deviation
http://en.wikipedia.org/wiki/File:6_Sigma_Normal_Distribution.jpg)
« Last Edit: 07/06/2011 10:53 AM by LendMeYourYears »

Offline rdale

  • Assistant to the Chief Meteorologist
  • Senior Member
  • *****
  • Posts: 9892
  • Lansing MI
  • Liked: 236
  • Likes Given: 21
Re: STS-135 Launch Weather Thread
« Reply #53 on: 07/06/2011 11:40 AM »
Hmm, is there a way you could use that in a sentence for me? I've seen sigma referred to in particular storm features (i.e. "The 500mb heights are 4 sigmas deeper than the mean for this time of year") but not sure how you would phrase it with "My high forecast of 89* could be 4 sigmas off"?

Offline psloss

  • Veteran armchair spectator
  • Senior Member
  • *****
  • Posts: 16935
  • Liked: 1012
  • Likes Given: 447
Re: STS-135 Launch Weather Thread
« Reply #54 on: 07/06/2011 11:51 AM »
Morning forecast from SMG.  Not much change... RTLS forecast has showers and thunderstorms, as relating to the launch window on Friday.

Quote
NOAA/NATIONAL WEATHER SERVICE
SPACEFLIGHT METEOROLOGY GROUP / WS8
LYNDON B. JOHNSON SPACE CENTER
HOUSTON TX              77058
700 AM CDT WEDNESDAY JULY 06 2011

LANDING FORECAST FOR STS-135

EXPECTED LAUNCH TIME:      1526Z
                DATE:      07/08/11

 RETURN TO LAUNCH SITE (RTLS) - VALID LAUNCH TIME + 25 MINUTES
 SHUTTLE LANDING FACILITY...  KENNEDY SPACE CENTER FL
 KSC  SCT030 BKN080 BKN250           7              21008P12
      SHRA/TSRA WI 20NM

 TRANS-OCEANIC ABORT LANDING SITES (TAL) - VALID LAUNCH TIME + 35 MINUTES

 ZARAGOZA...SPAIN
 ZZA  FEW040                         7              34006P09


 MORON...SPAIN
 MRN  SKC                            7              32005P08


 ISTRES...FRANCE
 FMI  FEW035                         7              18008P12


 ABORT-ONCE-AROUND SITE (AOA) - VALID LAUNCH TIME + 90 MINUTES
 NOR  SCT200                         7              15006P09


 PRIMARY LANDING SITE (PLS) - VALID 07/08/11 20Z TO 07/08/11 21Z
 EDW  SKC                            7              23010P17


 FLIGHT RULE VIOLATIONS:
 KSC ... LIGHTNING/PRECIP/TS
 EDW ... NONE
 NOR ... NONE
 ZZA ... NONE
 MRN ... NONE
 FMI ... NONE

THE NEXT SCHEDULED FORECAST WILL BE ISSUED 07/1130Z

« Last Edit: 07/06/2011 11:53 AM by psloss »

Offline vanoord

  • Full Member
  • ****
  • Posts: 475
  • Liked: 285
  • Likes Given: 37
Re: STS-135 Launch Weather Thread
« Reply #55 on: 07/06/2011 12:25 PM »
@NASA on Twitter:

Quote
Updated STS-135 weather forecast - there is a 30 percent chance of favorable weather for Friday’s 11:26 a.m. EDT launch of shuttle Atlantis.

Offline LostInSpace

  • Full Member
  • **
  • Posts: 250
  • Cape Canaveral
  • Liked: 12
  • Likes Given: 6
Re: STS-135 Launch Weather Thread
« Reply #56 on: 07/06/2011 12:30 PM »
Probability of KSC weather prohibiting launch:    70%
Probability of KSC weather prohibiting tanking:    20%
Primary concern(s):    Showers/Thunderstorms within 20NM of the SLF, Flight Through Precipitation, Cumulus Clouds

Probability of KSC weather prohibiting launch for 24-hour delay:    60%
Probability of KSC weather prohibiting tanking:    20%
Primary concern(s):    Showers within 20NM of the SLF, Cumulus Clouds

Probability of KSC weather prohibiting launch for 48-hour delay:    40%
Probability of KSC weather prohibiting tanking:    10%
Primary concern(s):    Showers within 20NM of the SLF, Cumulus Clouds

Offline psloss

  • Veteran armchair spectator
  • Senior Member
  • *****
  • Posts: 16935
  • Liked: 1012
  • Likes Given: 447
Re: STS-135 Launch Weather Thread
« Reply #57 on: 07/06/2011 12:42 PM »
For the synopsis, etc., the 45th Weather Squadron forecast is available here:
http://www.patrick.af.mil/shared/media/document/AFD-070517-025.pdf

Looks like with the showers now in the forecast, that brings the flight through precip violation on the launch side.

Also looks like the forecast is for a little worse weather on Saturday and Sunday...looks like that's with the forecast for the wave to stall.

Probability of KSC weather prohibiting launch:    70%
Probability of KSC weather prohibiting tanking:    20%
Primary concern(s):    Showers/Thunderstorms within 20NM of the SLF, Flight Through Precipitation, Cumulus Clouds

Probability of KSC weather prohibiting launch for 24-hour delay:    60%
Probability of KSC weather prohibiting tanking:    20%
Primary concern(s):    Showers within 20NM of the SLF, Cumulus Clouds

Probability of KSC weather prohibiting launch for 48-hour delay:    40%
Probability of KSC weather prohibiting tanking:    10%
Primary concern(s):    Showers within 20NM of the SLF, Cumulus Clouds

« Last Edit: 07/06/2011 12:48 PM by psloss »

Offline rdale

  • Assistant to the Chief Meteorologist
  • Senior Member
  • *****
  • Posts: 9892
  • Lansing MI
  • Liked: 236
  • Likes Given: 21
Re: STS-135 Launch Weather Thread
« Reply #58 on: 07/06/2011 12:52 PM »
Nothing changing from my vantage point other than the rest of the weekend looking worse than my original forecast. I wouldn't even go with a 50/50 shot on Sunday.

Offline jsmjr

  • Full Member
  • **
  • Posts: 297
  • Washington, DC
  • Liked: 26
  • Likes Given: 20
Re: STS-135 Launch Weather Thread
« Reply #59 on: 07/06/2011 01:03 PM »
Nothing changing from my vantage point other than the rest of the weekend looking worse than my original forecast. I wouldn't even go with a 50/50 shot on Sunday.

Question about process:  As the forecast seems to be worsening as we get closer to the original launch window, there presumably comes a point where they make a pre-emptive decision not to try, right?  Since we're beyond the last FRR, is this a decision by the NTD?  Does it take a 100% chance of negative conditions or something else? Do they wait until tanking at T-6 hours? Until RSS retract at T-11 hours?

(This is NASA, so I'm sure there's a 50-page document answering these questions in detail.)

Tags: