Chat with Steve Sokol, Lead Forecaster
NASA Johnson Space Center
April 1,1998 - 10:00 a.m.

[ Linda/NASAQuest - 6 - 09:56:46 ]
Good Morning (at least from California) We're ready to start.

[ Linda/NASAQuest - 7 - 10:00:35 ]
Here is an email question from Thomas Tobba: I live in Mauritius island in the south Indian ocean, and it will not be possible for me to participate to the chat with Mr.Sokol, because of the time here !! So my questions are: - During your flight in "Hurricane HUGO" which gusts did you record? - How can you explain the unactive tropical cyclonic season (November 97-May 98) in the south Indian ocean ? El Niño? - Are there any site on the internet, where we can have high resolution NASA satellite pictures of the Indian ocean?

[ Steve/JSC - 11 - 10:05:00 ]
Hi Thomas, We had a large area northeast of Charleston,S.C. that had 140 to 165 knot winds at flight level(10,00 feet) The resultant surface winds tore up Charleston and large forests to the northeast Yes, probably El Niño. E mail Scott Gennari at Univ of Hawaii(gennari@Hawaii.edu) He can get you the sites. Or go through Allentown Weather Center(Yahoo)

[ Mike-Mike/AlexanderDawsonb - 35 - 10:24:11 ]
What kind of weather delays a launch? How bad does it have to be?

[ Steve/JSC - 19 - 10:12:05 ]
RE: [Linda/NASAQuest] An email question from Mrs.. Parmely/Solana Vista School: What kind of weather is needed for the space shuttle to take off and land?
Mrs. Parmely and Mike, Very good weather. There are many requirements and it even differs with day or night launches; length of missions, etc. But the basic requirements are. No showers or thunderstorms within 20 miles...crosswinds less than 15 knots; cloud ceiling/Visibility(cig/vsby) greater than or equal to 500 feet/5 miles. At least one overseas site in Africa or Spain must be available for possible abort landings 35 min after launch...as well as at the Kennedy Space Center 25 minutes after launch. At the end of mission(EOM) the same basic requirements are in effect but the cig/vsby has to be 800 feet/5 miles. For night landings crosswinds have to be less than 12 knots.

[ Linda/NASAQuest - 20 - 10:12:26 ]
RE: [Betsy-Betsy/PennStatePublicBroadcasting] Hi Steve and Linda. I am enjoying listening in on your chat from What's In the News at Penn State. I may be joined later by some of our interns.
Hi Betsy, Good to see you online.

[ Steve/JSC - 22 - 10:13:56 ]
RE: [Karen-Karen/BigforkElementary] What kind of plane do you fly in bad weather?
Hi Karen, WC-130(USAF) for most USAF missions...a NOAA P-3 for Hugo.

[ Steve/JSC - 26 - 10:17:44 ]
RE: [zealan-MariaElena/SolanaVistaElementarySchool] What is a typhoon?
Maria Elena, A typhoon is a large low pressure area with a warm core and cyclonic(counterclockwise) rotating winds. It is called a Hurricane east of 180 degrees longitude. It is called a typhoon west of 180 degrees longitude. I once flew into Hurricane Dot east of Hawaii...which became Typhoon Dot west of Hawaii(at 180 degrees)...and then recurved to become Hurricane Dot when it crossed over 180 degrees again.

[ Steve/JSC - 32 - 10:22:16 ]
RE: [Wes-Wes/AlexanderDawsonSchool] If there was a bad weather condition that prevented a launch, how long could you delay with out having to abort the mission all together??
Good question Wes. We can usually tank(load with fuel etc) and go 2 to 3 days before we have to stand down. Sometimes we have advised them not to tank if the weather will be bad on launch day...this saves about 700,00 dollars. It saves a million if they do not have to land at Edward in California and ferry back. Our weather office in Houston(Spaceflight Meteorology Group) advises the flight directors on all planned and/or emergency laning fields. The USAF weather office in Florida has launch responsibility. We work closely with them...since they will not launch if emergency sites are not available.

[ Steve/JSC - 45 - 10:33:26 ]
RE: [Danny-Jean/JeffersonElementary] What was it like in the typhoon?
Danny-Jean, Each typhoon is different. They are all similar in structure to a Donut surrounded by a pinwheel. on the way to and from the storm the air is sinking and the clouds are fair-weather cumulus. As you get within 200 to 500 miles of the storm long feeder bands of thunderstorms spiral into the storm and you occasionally have to fly though a rough one. As you get within 200 miles or so the sky becomes very gray and the winds increase. There is a solid wall of thunderstorms that make up the donut..with an eye in the middle. Often the eye is clear...but sometimes it has lots of low clouds in it. Since the wall cloud is made up of solid thunderstorms it can get very rough and be filled with continuous lightning and moderate to severe thunderstorms. Usually you have a strong sinking sensation just outside the wall cloud...followed by a strong updraft in the wall cloud...and then a very strong sinking feeling as you enter the eye. The eye has a stadium effect with the clouds sloping up and out. Under the wall cloud the ocean is green-white streaks with huge waves. You approach the storms with the left wing of the aircraft into the wind(since the winds are counterclockwise you are thus headed for the low pressure center. As you get closer to the storm the 100 to 200 mph winds push(drift you to the right so you have to aim high to the left of the storm...otherwise you will keep getting spit out of or right into the wall cloud...and suffer the effects of severe thunderstorms. I did this for an hour and a half near Wake Island in the Pacific once. Most typhoon flight were 10 to 13 hours in length.

[ Steve/JSC - 49 - 10:36:27 ]
RE: [Amanda-Jean/JeffersonElementary] Have you ever been interested in another job other than the job you have now?
Amanda Jean, I almost went into YMCA work after Univ of Wisconsin but the Southeast Asia war came along...and the USAF needed weathermen...so since my major was Meteorology I got to use it operationally. I have also sold real estate, worked at Service Merchandise, taught karate and worked in a sports center.

[ Steve/JSC - 51 - 10:41:43 ]
RE: [Karen-Karen/BigforkElementary] How do you figure out when there is a chance of snow?
Karen, A lot of factors...but you have to have enough moisture...usually a low presure area...uplift from the ground(especially in the mountains). ..Vorticity increasing(cyclonic spin of the air) and usually 0 to -5 degree centigrade temperatures around 500 feet. At the surface it can actually snow at 40 degrees F and below if the temperatures are below 32 F aloft. Surface temperatures from 20 F to 30 F seem to produce heavy snows...since the warmer air is the moisture it can hold. Thundersnows produce very heavy snows due to strong updrafts in the clouds.

[ Steve/JSC - 56 - 10:44:37 ]
RE: [Sarah/Greenmeadow] How far in advance will you be able to tell if the Neurolab mission will launch?
Sarah, In stable weather conditions we may have a good idea 10 days out...since our computer models can give us an idea out that far. But we really never know till the last few minutes. On one of my missions...the weather cleared up with less than 5 minutes to go but the computer shut down the engines with 1.9 seconds to go due to a hardware problem.

[ Linda/NASAQuest - 60 - 10:49:46 ]
Our hour with Steve Sokol is almost over. Let's give him a chance to answer as many of the questions posted as possible before adding new ones.

[ Steve/JSC - 63 - 10:51:39 ]
RE: [Linda/NASAQuest] Another question from Mrs.. Parmely/Solana Vista School: How is a typhoon different from our storms in southern California? What was it like to fly into a typhoon? Were you afraid?
Mrs Parmely, A typhoon is a large low pressure area so it is similar to the lows that bring storms to souther California. But it always has a warm core whereas a lot of lows are cold cores. The warm core and warm ocean temperatures help the typhoon/hurricane keep going...but it begins to die when the friction effects on land affect it. I didn't feel real scared..though occasionally swallowed hard and thought I might be a little crazy. We once had -3.5 Gs(gravity) in a severe thunderstorm right over Southeast Asia) and that was outside of a typhoon. The cockpit filled with flying debris, coffee, books and lunches. The loadmaster broke a leg. In 1974 a USAF crew disappeared between Hong Kong and Manila...and know trace was ever found of it. The Noaa crew that flew into Hugo 2 days before I did also had a close call. I believe only a few aircraft have been lost however.

[ Steve/JSC - 64 - 10:53:08 ]
RE: [Linda/NASAQuest] Hi Betsy, Good to see you online.
Hi Betsy...glad to have you. I am a little long winded but will be happy to hang on well beyond the ending time.

[ Steve/JSC - 65 - 10:54:51 ]
RE: [ally-MariaElena/SolanaVistaElementarySchool] How poisonous are Venus's clouds?
Sorry...don't know about Venus. I have enough to keep me busy with Earth's weather. Start with Yahoo search(Venus clouds)

[ Linda/NASAQuest - 66 - 10:54:59 ]
Thanks Steve. We've had some really enthusiastic folk here today. I know they'll appreciate your extra time!

[ Steve/JSC - 67 - 10:55:38 ]
RE: [Shannon-Jean/JeffersonElementary] Have you ever been hurt in a storm?
Shannon-Jean, No...Fortunately

[ Steve/JSC - 68 - 10:58:42 ]
RE: [karlita-MariaElena/SolanaVistaElementarySchool] How do you forecast the weather?
Karlita-Maria Elena, We use Satellite pictures, doppler radar, computer models of forecast moisture,vorticity, winds, fronts, pressure, etc. That is just a little of what we look at. Things are constantly variable in the ingredients that make up our atmosphere so it is a real challenge.

[ Steve/JSC - 69 - 10:59:39 ]
RE: [Trent-Jean/JeffersonElementary] How close does a funnel cloud have to be to the ground to be considered a tornado?
Trent-Jean, It has to touch the ground.

[ Steve/JSC - 71 - 11:01:46 ]
RE: [Karen-Karen/BigforkElementary] How old are you?
Karen, Ouch...I could plead the 5th...But I am a young 54...and still play basketball.

[ Linda/NASAQuest - 72 - 11:02:24 ]
RE: [KarenJ.Massey] Our group will need to go back to our class. We will read the rest of the questions and answers after school. We are enjoying your answers. Thank you for your time. Bye!
Thanks for joining us!

[ Linda/NASAQuest - 74 - 11:05:02 ]
RE: [Betsy/PennStatePublicBroadcasting] What a fun chat! Happy flying, Steve!
Neat to have you join us!

[ Steve/JSC - 75 - 11:06:32 ]
RE: [xavier-MariaElena/SolanaVistaElementarySchool] How do satellites tell us about weather?
Xavier, Satellites give a bird's eye(actually higher) view of the weather patterns around the world and how they interact. The infrared satellites cover the nighttime hours. Satellites are great for picking up the jet streams with their sharp edges. Water vapor and other special enhancements can feature certain things you are looking for...moisture low clouds/middle/high clouds/ Typhoon feeder bands...overshooting tops of particularly severe weather. We usually go to rapid scan for launch/landing and get pictures every few minutes instead of the usual 30 minutes to an hour.

[ Jean/JeffersonElementary - 76 - 11:09:31 ]
We have to get back to work now. Thanks for chatting with us! We will read the rest of the responses after school.

[ Steve/JSC - 77 - 11:11:54 ]
RE: [Amanda-Jean/JeffersonElementary] Why is the weather calm in the eye of a hurricane? Why isn't it windy there too?
Amanda, Good question. Actually the winds are whirling around the storm at up to 200 knots in some cases...so it's like being in the middle of a merry-go round. The winds are rising and whirling in the wall cloud and will soon be just as strong from the opposite direction as the eye passes over a certain spot on the earth. But other than a light and variable wind it is essentially calm with the lowest pressure at the center...and the warmest surface water temperatures...which is why aircraft still fly into storms to drop instruments(dropsondes) to measure and locate the center.

[ Linda/NASAQuest - 80 - 11:15:28 ]
RE: [Ashley/SouthShelby] Hello I am new here. So why don't you feel me in on what is going on.
Hi Ashley, Why don't you send me an email at lconrad@mail.arc.nasa.gov so I can give you some help. We are well past the hour that Steve Sokol volunteered to give us, and he's just wrapping up the questions he can before he has to stop. I'm glad you joined us. Hope you'll be able to make another chat while it is active.

[ Steve/JSC - 81 - 11:15:44 ]
RE: [MouaChee-Jean/JeffersonElementary] Why do tornadoes move and wiggle?
Tornadoes move and wiggle because they are constantly interacting with the environment around them...the air around them...and the ground below them. They favor certain combinations of pressure, moisture and winds, to form and prevail. They usually spin out of very strong thunderstorms with high tops...but smaller funnels can spin out of smaller storms.

[ Steve/JSC - 82 - 11:17:53 ]
RE: [Karen-Karen/BigforkElementary] How fast is the fastest typhoon?
Karen, I believe it happened last summer over Guam with an still unofficial 236 knots over Andersen AFB. Can't think of typhoon name right now.

[ Steve/JSC - 83 - 11:19:37 ]
RE: [KaBao-Jean/JeffersonElementary] How does it feel when you first entered a typhoon?
KaBao, See earlier response. Usually sinking then strong updrafts and thunderstorms in the wall cloud donut...then sinking and sudden clearing in the eye.

[ Steve/JSC - 84 - 11:21:39 ]
RE: [ally-MariaElena/SolanaVistaElementarySchool] How old will you be when you retire?
Ally, I may never retire... I had 4 kids...at least 2 still in college. Besides I like my job and still get plenty of time to enjoy my hobbies.

[ Steve/JSC - 85 - 11:27:47 ]
RE: [Katie-Betsy/PennStatePublicBroadcasting] Hi Steve. Have you ever been WAY off on a forecast? I'm the host of WHAT'S IN THE NEWS and I like to hear about other people's bloopers having made some good ones of my own.
Katie, I have to be right on for short range shuttle forecasts since once they deorbit burn over the Indian Ocean the shuttle will be landing in an hour in the U.S. And it cannot go to another airport since it is just a big glider at that time. On longer range forecasts I have probably been off on some since the atmosphere can reall affect the timing and occurance of weather. A friend if mine in the Air Force once forecast partly cloudy for a Colonel...when he was a young 2 Lt. The Colonel cornered him later and exclaimed "Lt. I shoveled 12 inches of partly cloudy off my driveway this morning!" This was in Langley Virginia after a Cape Hatteras low suddenly intensified overnight.

[ Steve/JSC - 86 - 11:29:07 ]
RE: [Richie-MariaElena/SolanaVistaElementarySchool] why did you name a typhoon a typhoon?
I believe it is from the Japanese expression for divine wind.

[ Steve/JSC - 87 - 11:30:12 ]
RE: [Katie-Betsy/PennStatePublicBroadcasting] Does Mars have weather and if so, are you able to forecast it on Earth?
No. And others in NASA know a lot more about Mars than me.

[ Steve/JSC - 88 - 11:35:42 ]
RE: [SatelliteGroup-KarenJ.Massey] Hi, Mr. Sokol. We read that you lived in Texas for awhile. We are second graders from Fort Worth, Texas. We are studying weather and we have a weather station on the playground. Our group question is "How long did the longest hurricane last?" Thank you.
Satellite Group. I live in Houston now. I spent 3 years at Sheppard AFB(1971-1974). ..and was actually born in Ft Worth,Texas...though I grew up in Iowa. I am not sure of the longest typhoon. Probably some of the Pacific storms have lasted for close to 2 weeks as a full blown typhoon(65 knots or greater). Of course they start forming even earlier and go through the tropical depression and tropical storm stages first. They will then usually continue until they hit land. So in the Pacific they can go for thousands of miles.

[ Steve/JSC - 89 - 11:39:00 ]
RE: [zealan-MariaElena/SolanaVistaElementarySchool] how long were you flying in the typhoon Dot east of Hawaii?
Zealan...flew for 3 or 4 days into Dot. Sorry just got interrupted by big NASA boss...but he just wanted a fishing forecast. See why this is a fun job? I can still keep answering questions though.

[ Steve/JSC - 90 - 11:40:24 ]
RE: [Andy-Jean/JeffersonElementary] How big can tornadoes get?
Andy, Tornadoes can range from less than 100 yards wide to up to half mile or more.

[ Steve/JSC - 92 - 11:44:47 ]
RE: [CometGroup-KarenJ.Massey] Our group wants to know if someone could design a Space Shuttle that could land or be launched in a storm. Thank you.
Comet Group. That would take pressure off us forecasters but might put us out of a job. The main problem now is we don't want the thermal protection heat tiles to get wet corrode and be damaged for re-entry...we don't want the pilot not to be able to see the landing aids...though they continue to try to perfect the auto-land system...and we don't want the shuttle to blow off a runway into the swamps, etc. And we don't want lightning to cause communications failure, or worse, a crash.

[ Steve/JSC - 93 - 11:47:43 ]
RE: [Trevor-Jean/JeffersonElementary] How old were you when you knew you wanted to have a job with weather.
Trevor, Nice question. 7 years old when a tornado and severe thunderstorms went through my neighborhood in Waterloo Iowa. The sky was greenish yellow before the storm and it moved in very fast. I told my folks it was coming...And they spent the rest of the storm trying to keep me in the basement. At least they had basements...which we don't in Houston.

[ Steve/JSC - 94 - 11:53:31 ]
RE: [TouVue-Jean/JeffersonElementary] Which is stronger - hurricane or tornado?
At various times a tornado and a typhoon can be equally strong..up to about 200 plus mile an hour winds. However, the highest winds in some tornadoes have been around 300 mph. A typhoon has a much broader scale of say, 50 to 100 mph winds, but the very strongest winds are tucked under the wall cloud...usually in the northeast quadrant of the storm. So, the worst place to have a storm hit the coast is just to your southwest. By the way, if you put your back to the wind and stick your left arm out it will be pointing to the center of the storm(counterclockwise rotation) Also by the way...these storms rotate clockwise in the Southern Hemisphere.

[ Steve/JSC - 95 - 11:55:50 ]
RE: [Linda/NASAQuest] You are truly a patient man!
Linda...Not according to some...say, for example my wife and kids. Ha!

[ Steve/JSC - 97 - 12:06:14 ]
RE: [Xai-Jean/JeffersonElementary] How old were you when you flew in Maria Elena?
Sorry, I probably answered it funny .I flew into Hugo in 1989 and lots of typhoons from 1969-71. One storm had an almost green wall cloud because of the dawn light being refracted through the moisture in the wall cloud as we flew into it east of Guam. It was hailing on us even though we were in the clear in the eye...because of the strong updrafts throwing the hail out of the nearby wall cloud. We also saw ships and flocks of birds in the eyes on a few occasions. We also seeded the fog in Alaska. Made rain in a few places...and dropped canned goods to the natives of some islands that had been damaged by storms...during our annual Christmas Drop for the Air Force in Guam.

[ Steve/JSC - 95 - 11:55:50 ]
RE: [ Linda/NASAQuest ] I want you to know how much I really appreciate this time you've given our classroom students. This has been very informative, and you've gone right through 2 hours! Wow! Thank you!
I also enjoyed it!