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Help solve a weather mystery

By: Dr. Jeff Masters, 7:55 PM GMT on November 17, 2006

The second in the series of Dr. Masters' vacation blogs.

Help solve a weather mystery

I'm often asked why it is that the Hurricane Hunters are unafraid to fly in extreme Category 5 hurricanes with 200 mph winds, but refuse to fly in garden variety thunderstorms with winds of perhaps 30 mph. Well, airplanes don't care about wind, as long as it's all moving the same direction at the same speed (i.e., there is no wind shear). Granted, some hurricanes have outrageous wind shear that creates severe turbulence capable of damaging the airplane. However, threats of this nature pale in comparison to the chief hazard of flying into thunderstorms--hail. Even small hail poses a significant threat to airplanes. Hurricanes rarely have hail, except at high altitudes in some of the stronger storms. On a mission I flew into Category 3 Hurricane Emily of 1987, one of our airplanes encountered pea-sized hail in the eyewall at 18,000 feet, and the ice scoured off the airplane's paint job in some places. More seriously, hail damaged two of the engines, causing oil leaks that forced the airplane to abort the mission after a record 34 penetrations of the hurricane's eyewall.

Large hail can seriously damage an airplane, as seen in the incredible photos below. These origin of these photos is unknown, but they have been circulating on the Internet for a few months. Presumably, they were taken on August 10, 2006, but no one knows where. If you can shed some light on this mystery, drop flightglobal.com and myself an email.





Armored T-28 hail research aircraft retires
Speaking of hail and airplanes, the world's only aircraft equipped to safely to fly into mature thunderstorms, the South Dakota School of Mines & Technology's armored T-28, is being retired this year after over 900 penetrations of thunderstorms and 37 years of service. The famed aircraft, which has survived updrafts as strong as 115 mph, 2-inch hail, and numerous lightning strikes, will go on display at the Strategic Air and Space Museum at Ashland, Nebraska. The National Science Foundation has requested to the Pentagon that a two-engine A-10 Thunderbolt aircraft be made available as a replacement. A two engine hail penetration aircraft is a good idea! I spoke with one of the pilots of the T-28 back in 1987, during a thunderstorm research program I was involved with. The pilot told me that he had done several "dead stick" landings on highways after lightning strikes had knocked out power to the single engine of the T-28.

Here's the specs on the special modifications the T-28 aircraft had, taken from the web site above:

The leading edges of the wings and tail surfaces are covered with 2.29 mm (0.090 inch) 2024T4 heat-treated aluminum sheets formed to fit and bonded to the existing wing and tail surfaces. The tops of the wings are covered with 0.81 mm (0.032 inch) sheets of the same material. The leading edges of the cowling are covered with an additional sheet of fitted 3.18 mm (0.125 inch) aluminum. This armor plating adds about 318 kg (700 lb) to the aircraft weight.

The carburetor is protected from ingestion of large hailstones by the addition of a metal grate to the air intake to break up the hailstones prior to entry. A similar device was installed over the oil cooler intake to prevent damage to the relatively fragile oil radiator.

The canopy also required substantial modification since the standard Plexiglas bubble canopy was much too weak to withstand encounters with large hail. The windshield was replaced with flat sheets of 1.91 cm (0.75 inch) stretched acrylic and the side panels were made of flat sections of 1.52 cm (0.60 inch) stretched acrylic. The windshield and the leading-edge armor were tested to withstand 7.6-cm diameter hail at penetration velocities by firing ice balls from a specially-built hail "cannon" at test sections of the aircraft.


Figure 1. The South Dakota School of Mines & Technology's armored T-28 weather research aircraft. Photo taken by Jeff Masters in June, 1987 in Huntsville, Alabama during T. Theodore Fujita's Microburst and Severe Thunderstorm (MIST) field program.

Jeff Masters

Aviation

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Snow and blizzards are the opposites of Tropical Stroms and Hurricanes. If I may impose a thought or two about this. I'm a Minnesotan. Up here, it seems whenever we get our first true snow storm, the roads (even though crews work around the clock to keep them dry) become obstacle courses of cars and trucks spinning our of control, because these people think they can still handle going the speed limit on slick spots (60 mph). Visibility is strained in a heavy snowfall too, so people turn on their brights to compensate, thus blinding incoming traffic. It take a few nasty storms to retrain us the dry safely through it or to not drive in it at all. So here's my question to you guys in balmier weather. When tropical season starts, do people go about their normal business in a tropical storm, or do they avoid driving altogether? Thanks for your comments.
sorry for the typos everyone. I'm lazy today.
in a TD in florida, people continue to all of their normal activities (except the park).
in a TS, however, depending on the severity of it, there will be a lot of people or just a few people.
Then would you say, that a Tropical Storm is just like heavy blowing rain showers? Do more auto accidents occur under these conditions?
Rain X & good tread is all you need in a TS.
yes, that pretty much is TS. I don't think that more accidents happen in them considering I haven't gotten a TD or even a TS for that matter in quite some time. Even though i'm in St. Pete, FL.
I guess my point is do you think that adverse (precip, wind, visibility, etc.) driving conditions should impede all driver's discretion to go at posted speed limits? I can understand emergency vehicles because time is in the balance, but anyone else should at least slow down and drive with both hands on the steering wheel, right guys? Thoughts please.
Yes, you are right.
Has Florida ever had a snow event occur where the precip stuck on the ground for longer than a few days? My guess is no, but you'd know best.
While doing the morning update on my blog I ran across this....
invest 98E.
20/1200 UTC 11.7N 115.6W T1.0/1.0 97E
20/1145 UTC 8.5N 91.9W TOO WEAK 98E
20/1145 UTC 15.1N 106.8W T2.5/2.5 SERGIO
20/0600 UTC 10.9N 114.8W T1.0/1.0 97E
20/0600 UTC 14.7N 106.5W T2.0/2.5 SERGIO
20/0545 UTC 8.1N 91.1W TOO WEAK 98E
19/2330 UTC 11.1N 114.4W T1.0/1.0 97E
19/2345 UTC 8.1N 90.3W TOO WEAK 98E
19/2345 UTC 15.0N 106.2W T2.0/3.0 SERGIO
19/1745 UTC 7.7N 90.0W T1.0/1.0 98E

There is no mention of it on either Navy site....
I am not aware of a snow event in Florida where the snow stayed on the ground. Maybe in NW Florida. I do know that some of the metal bridges have iced up in N Florida. Wind with freezing temps cool the structures faster. Then it just takes a minimal amount of moisture to make a conditions that many natives aren't ready for.
513. MahFL
I see one or two suspicious curving bands of clouds off the NE FL coast.
I'm a paramedic in Broward County Florida. I was working during Katrina's pass across S. Florida and the storm didn't seem to keep the people off of the streets. As a matter of fact I ran two calls on the interstate during the height of the storm. (minimal hurricane winds) It wasn't a whole lot of fun but of course Wilma wasn't the monster then that she bacame when she hit the Gulf.
515. MahFL
Where I live in NE FL, even normal rain showers send drivers crashing into each other, they just do not slow down.
To add to this adverse driving weather discussion, I've been discouraged by this rampant polularity of street racing in the late night hours in Minnesota. Do these people understand what black ice is? At night, it's nearly impossible to see. Fearless drivers at night, they speed down major streets in their modified Honda Civics. When an accident occurs, it seems to silly to have a pause of sympathy for these daredevils on the streets, becasue they endanger us every night. Thoughts please.
517. MahFL
They should not be street racing ever, end of discusion.
There have been more high speed police chases this year too. It's probably because of the nicer weather (no snow) that we've been having so far. The police take a great risk too in engaging in high speed chases late at night. I think if someone needs to get away that bad, send the helicopter after them and wait for them to make a mistake, right guys? Why endanger other drivers with addition squad cars trying to apprehend the suspect?
Just like people who joyride in the middle of a hurricane, these people have no regard for their lives. If they want to kill themselves, so be it. The problem is, they are endangering everyone else on the hiway and then when they do get hurt they expect people like me to put our necks on the line to come save them.
I guess that's my point guys. Adrenalin junkies that can't fulfill their needs from TV broadcasts like to put everyone's life in jeapordy just to keep their life interesting. Sorry, but I'll choose boredom or normalness over stupidity everytime. How about you guys/gals?
I've spent 30+ years on the streets as a medic. I've been shot at, chased several times by people with knives, bitten and involved in several accidents. And that was AFTER I got back from Viet Nam. I'll be retireing soon and look forward to walking the dogs as the most exciting thing I do during the day. I will never understand those people. But as we say in the rescue bizz...If it wasn't for stupid people we wouldn't have a job.
If they drive like terrorist,treat them as such.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
1000 AM EST MON NOV 20 2006

.DISCUSSION...
MORNING UPDATE...EXCEPT FOR THE FAR NORTH...MOST OF THE CWA IS
EXPERIENCING FILTERED SUNSHINE DUE TO MOSTLY CLOUDY SKIES AT THE MID
AND UPPER LEVELS. MID/UPPER LEVEL CLOUDINESS SHOULD STAY WITH US FOR
THE DAY AS LATEST RUC RUN SHOWS THAT THE 250MB JET AXIS WILL REMAIN
NORTH OF OUR AREA THROUGH THE EVENING. WEST TO NORTHWEST WINDS WILL
SLOWLY INCREASE AS TROUGH OF LOW PRESSURE OFF THE GA/SC COAST
DEVELOPS INTO A CLOSED SURFACE LOW BY THIS EVENING. LATEST MSAS
SURFACE WIND STREAMLINES AND BUOYS OFF THE SC/GA/FL COAST ALREADY
INDICATING A CLOSED (OR NEARLY CLOSED) LOW.
MAY SHAVE A DEGREE OR
TWO OFF TODAYS MAX TEMPS DUE TO AMOUNT OF MID/HIGH CLOUDINESS.
Posted By: Canetankerous at 11:36 AM
...I ran two calls on the interstate during the height of... Wilma...


Don't mean to sound like a commercial, but I credit Rain-X with allowing me to see & stop my driver (Engine) before hitting a power line at windshield height at night during Gordon '94.

'tank - what is your cutoff wind speed down there?
525. MahFL
My HWO for Tues.
"ISOLATED TO SCATTERED RAIN SHOWERS ARE EXPECTED FROM TONIGHT THROUGH
WEDNESDAY. THERE IS A SMALL CHANCE THAT THESE "COLD" RAIN SHOWERS
COULD BE MIXED WITH FROZEN PRECIPITATION AT TIMES FROM LATE TONIGHT
THROUGH TUESDAY NIGHT MAINLY OVER SOUTHEAST GEORGIA AND NEAR THE
COAST. SURFACE TEMPERATURES ARE EXPECTED TO REMAIN ABOVE FREEZING SO
NO SIGNIFICANT IMPACTS ARE EXPECTED AT THIS TIME.

Could be snow/sleet in JAX FL.
Feb 9 1973 2 inches on the ground at my home.
Preceded by significant icing event.
I live right at the coast.
PensacolaDoug, That's amazing to hear. On the coast you say? You'd think that the warmer climate you live would melt the snow by the next day. If you say 1973, that much me a rare case indeed. Thanks for sharing that unusual event with me. Now I've got one for you. Back in 1979 I was helping my father pick up our neighbor's yard (my dad owned the property and was getting ready to rent it out). It was unusually cold on this Saturday morning in June. When what to my suprise, the sky dropped big wet heavy snowflakes. It only lasted for about 10 minutes, but it has never been repeated in the Twin Cities anyway.
Has anyone ever been struck by lightning on this blog?
LOL...
Then why do you call yourself cyclonebuster? You should've called yourself lightningrod, right? LOL Were you unconscious?
I don't go out when it's stormy. Once you've been hit by lightning, I think for some reason it's more likely it will try to strike you again, but I don't understand why this would be. Does it have something to do with ionization occuring within the body or even a electrophysiological field of sorts that enhances the suceptibility of receiving future lightning strikes. I wish I could just call it a strange coincidence, but I've been struck three times and somehow still live to tell about it.
Do you think that the moderate El Nino event of 2006 going into 2007 will make the tropical forecast even less eventful for the Atlantic basin than this year?
534. Inyo
latest ENSO advisory is out... the 'weakening' el nino of last week has totally been reversed.

I dont feel that El Nino has affected the continental US though, cold in florida, dryness in southern California, and flooding in Seattle are not signs of El Nino at all. My guess is since it is late onset, it is not yet doing much.. but that should change soon.

long range models show that the rainy season in southern california may finally start in early December
Inyo hey what about me i like is ca 2 i live in sonora what dos the long range models show for me?
Judging by the accuracy of this years El Nino and La Nina forcast, I think I will wait to see the state of things next summer before making any calls.
Since El Nino only really affected the latter part of this year's hurricane season, next year could be even less active (some forecasters now say that El Nino will last through the end of next year).
By the way, Dr. Gray already released his summary/verification for the 2006 season (shows how dead the season has been... LOL); besides the obvious, it has some surprises in it; for example:

The 2006 hurricane season had the following special characteristics:

Another early-starting season. Alberto formed on June 11. The climatological average date for the first named storm formation in the Atlantic, based on 1944-2005 data, is July 10.

Nine named storms formed during the 2006 season. This is the fewest named storms to form in the Atlantic since 1997, when only seven named storms formed.

Five hurricanes formed during the 2006 season. This is the fewest hurricanes to form in the Atlantic since 2002, when four hurricanes formed.

Two major hurricanes formed during the 2006 season. 1997 was the most recent year to have fewer than two major hurricanes form (1 Erika).

50 named storm days occurred in 2006. This is the lowest value of named storm days since 1997, when only 28.75 named storm days occurred.

20 hurricane days occurred in 2006. This is the lowest value of hurricane days since 2002, when 10.75 hurricane days were observed.

3 intense hurricane days occurred in 2006. This ties 2002 for the lowest value of intense hurricane days observed since 1997, when only 2.25 intense hurricane days occurred.

Only one hurricane formed during August. This is the fewest hurricanes to form in August since 2002, when no hurricanes formed.

September 2006s NTC value was 66. This is the ninth straight September with NTC exceeding the climatological average of 48. The last September with below-average NTC was 1997, when only 28 NTC units were accrued.

18.25 hurricane days occurred in September 2006. This is more than were observed in September 2005 (16.75 hurricane days).

No named storms formed in October. This is the first time that no named storms have formed in October since 2002. Prior to 2006, only eleven years since 1950 witnessed no named storm formations in October.

Only two named storm days were observed in October (from Isaac which formed in late September). This is the fewest named storm days in October since 1994, when zero named storm days were observed.

The season accumulated 85 NTC units. This is the lowest NTC value since the 2002 season which accrued 82 NTC units.

No Category 4 or 5 hurricanes formed in the Atlantic basin this year. This is the first year with no Category 4-5 hurricanes in the Atlantic since 1997.

Three named storms made United States landfall in 2006. This is the fewest number of named storms to make landfall in the United States since 2001 when three named storms (Allison, Barry and Gabrielle) made landfall.

This is only the 11th year since 1945 that no hurricanes have made United States landfall.

From Alberto-Helene, each tropical cyclone lasted as long or longer than the cyclone preceding it. For example, Alberto and Beryl lasted 2.75 named storm days, Chris and Debby lasted 3.25 named storm days, Ernesto lasted 6 named storm days, etc.

Both Gordon and Helene accumulated 7.5 hurricane days. These two storms accrued as many hurricane days as Wilma, which was the longest-lived hurricane of the 2005 season.


Makes you wonder (bolded parts) what could have happened this year if El Nino hadn't formed and the steering patterns had stayed the same as in 2004-2005... Interestingly, El Nino does not affect September much; in fact, 2002 has the record for most storms in September (8) and it had an El Nino.

Not mentioned:

The strongest storm (120 mph and 955 mb, tie between Helene and Gordon) was the weakest since 1994 (windspeed or pressure).
Thank MichaelSTL- that pretty much sums up this year tropical activity. I guess September was more active, as if the hurricane gods would have us believing that "it's not over until the hurricane season is over." This was certainly true with Wilma in '05. Dr. Masters' repeatedly eluded to 2005 as being an unusually active hurricane season. More records were broken in that year than any other. (Records on the more scale). Would you say statistically speaking, that the years 2004 and 2005 displayed an outlier of hurricane activity that could be skewing the data received from all recorded hurricane activity (since recording hurricane active began in the 19th century)? If so, how can we be sure that more active hurricane seasons are on the way? Everything about tropical weather seems so speculative, even with the technology they have in use today. The one thing is quite disturbing about larger hurricanes formed in the past is their ability to intensify in a relatively short period of time. This is what catches my attention, not stuff like Hurricane Vince of '05 or that a record 28 (i may be wrong on this as I don't care to check it) named storms happened in '05. Intensification is far more dangerous to human life than how many tropical storm days or even hurricane days have occured. Which brings me to this question? Since hurricanes survive mostly over ocean waters, their intensity becomes greatly compromised when traversing over land. What has been the longest lasting hurricane event that occured on any land mass on earth that is known and recorded as such? Thanks for your comments.
The pilot advised of a lightening strike resulting in a cracked window. The aircraft returned to Calgary and landed safely at 03:00Z. There was no operational impact.

UPDATE: 727 was operating a flight from Calgary, AB to Minneapolis, MN. While in cruise at FL300 after departing Calgary, a thunderstorm was encountered with severe turbulence, heavy hail and lightening. The windshields, nose section and radome, radar, wing leading edges, engine inlets, etc were damaged. The crew initiated emergency procedures and began a descent. ATC was contacted, an emergency was declared, and the aircraft was cleared for a return to Calgary for an uneventful landing. The aircraft remains in Calgary while the operator arranges for a ferry flight to their overhaul facility.


i called the carrier todaty..and they confirmed that this did indeed happen...as i mentioned in another cut and paste..two flight members quit as soon as they landed and the compnay confirmed that indeed happened also
Good afternoon,

There is a circulation currently in the western caribbean spinning in the mid-levels.The NHC in there 1:05 discussion seems to think it maybe making its way down to the surface....

NHC @ 1:05PM today.

THE CARIBBEAN SEA...
A LARGE AREA OF SCATTERED MODERATE CONVECTION EXISTS IN THE
CNTRL/WRN CARIBBEAN BETWEEN 74W-82W WHICH INCLUDES THE ISLANDS
OF JAMAICA AND ERN CUBA. THIS UNSETTLED WEATHER IS ASSOCIATED
WITH A SFC TROUGH WHICH EXTENDS FROM THE ATLC ACROSS THE BAHAMAS
ALONG 21N73W 17N79W 11N80W. A 1048 UTC QSCAT PASS INDICATED A
PRONOUNCED WIND SHIFT WHERE NLY 20-25 KT WINDS ARE COMMON W OF
THE TROUGH AXIS AND LIGHTER E TO NE WINDS ARE E OF THE AXIS. IN
ADDITION...VISIBLE IMAGES SHOW MID-LEVEL ROTATION IN THE CLOUDS
NEAR 16N80W. IT IS POSSIBLE THAT A SFC LOW PRES SYSTEM MAY BE
FORMING IN THAT VICINITY
. UPPER LEVEL SWLY-WLY WINDS...NEAR AND
W OF AN UPPER RIDGE AXIS ALONG 72W...ARE SPREADING MOISTURE
AROUND THE RIDGE...BUT MUCH OF THIS IS QUICKLY DRYING OUT ON THE
DESCENT NLY BRANCH ABOVE THE ERN CARIBBEAN. ISOLATED SHOWERS ARE
N OF 15N BETWEEN 66W-74W. OTHERWISE...CONDITIONS ARE FAIRLY
QUIET ACROSS THE REMAINDER OF THE E ATLC. GFS SHOWS THE DEEP
MOISTURE SWATH LINGERING BUT SHRINKING IN SIZE OVER THE NEXT
COUPLE DAYS IN THE CNTRL/WRN CARIBBEAN


Some one asked earlier about the toronado warning and striking times. I received the alert at 06:34 and damage reports were made before 7 am. Some of the estimates were touchdown in less than 10 minutes. Portions of the path F-3 damage, 300 yards wide.Snow in the mountains. Here on the coast 30 to 40 mph wind and a flood watch and warnings.in North carolina
Ric,
What has me curious is why they quit. Was it because the storm scared them so badly or was it because they refused to fly with that stupid captain again?
sorry! that is in North Carolina.