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Meteorology              Charles A. Giannetta
                         Meteorologist - Professor 
Pages
 
"Thunderstorms"

1.  Thunder: A low sound produced by lightning: Produced by the
             rapid expansion of air from the intense heat of 
             lightning discharge.

2.  Thunder: Can be heard form ablut 10 miles.
3.  Thunder: Is a rapid expansion of air molecules.
4.  Thunder: Sound travels about 1,000 feet per second.
5.  Thundersnow: Snow with a hunderstorm.
6.  Thunderstorm: A nesoscale weather system with thunder and
                  lightning that reach heights of 60,000+ feet
                  into the stratosphere.

1.  Tstorms: About 40K-50K eaxh 24 hours, Mostly over the equator.
2.  Tstorms: Cumulonimbus name given to tstorm cloud. (CB)
             Cumulus meaning Puffy. Nimbus mening rain.
3.  Tstorms: During the disipating stage only the downdraft is present.
4.  Tstorms: During the mature stage the up & downdraft are present.
5.  Tstorms: During the 3rd. stage (Dissipating) the tstorm has begun to die.
6.  Tstorms: Duration 1 to 24 hours.
7.  Tstorms: Freezing level 32 degrees F.
8.  Tstorms: Gust front.
9.  Tstorms: Hail: Hail shaft: Hail Streak:
10. Tstorms: Hail: One of the largest hailstines fell in Nebraska in 1928.
             It was 17 inshes around & weighed 1.5 lbs.

11.  Tstorms: Hail Size: Golfball: Baseball: Grapfruit:
12.  Tstorms: Hail Size: Pea: 1/4 inch: Marble 1/2 inch.
13.  Tstorms: Hail: Sometimes there are 25 layers of large hailstones.
14.  Tstorms: Imbedded: Clusters: Merging: Multicell:
15.  Tstorms: Isolated: Extremely small number: Few 15% or less of area
              or line. Scattered 16& to 45% of an area/line: Numerous
              45%+ of area/line:
16.  Tstorms: Light: Moderate: Severe:
17.  Tstorms: Macroburst: A downburst that affects a path on the ground
              longer than 2.5 miles.
18.  Tstorms: Microburst: A downburst that affects a path on the ground
              shorter han 2.5 miles.
19.  Tstorms: Million of lightning strikes per hour.
20.  Tstorms: Movements and wind speeds.

21.  Tstorms: Occur daytime or nighttime: Anytime:
22.  Tstorms: Occur in 3 stages: 1. Cumulus: 2. Mature: 3. Dissipating
23.  Tstorms: On Earth 2,000 thunderstorms occur each hour. 40K-50K 
              each 24 hrs. Mostly over the equator.
24.  Tstorms: Produce downbursts:
25.  Tstorms: Produce heavy amounts of rainfall.
26.  Tstorms: Produce a Scarf and Anvil Cloud at the top.
27.  Tstorms: Release latent heat to the atmosphere.
28.  Tstorms: Roll Cloud produced in front on a thunderstorm.
29.  Tstorms: Temperatures: Falling:
30.  Tstorms: Severe Thunderstorm Warning 1 hour. Issued by the
              National Weather Service (NWS).

31.  Tstorms: Severe Thunderstorm: 50 mph wind: 3/4 inch hail.
32.  Tstorms: Squal Lines: Very violent weather: Act as a check valve.
33.  Tstorms: Supercells to 60,000+ feet and may last 24 hours.
34.  Tstorms: Tornadoes: Southwest side of severe thunderstorm.
35.  Tstorms: Training Effect: One after another moving in the same 
              direction.
36.  Tstorms: Thunderstorms reach up to the stratosphere 50K to 60K+ Ft.
              Rise aboue the tropopause.
37.  Tstorms: Up & down drafts can reach speeds as fast as 200 mph.
38.  Tstorms: Stage 1: Cumulus:
39.  Tstorms: Stage 2: Mature:
40.  Tstorms: Stage 3: Dissipating:




Meteorology              Charles A. Giannetta
                         Meteorologist - Professor 
 
"T H U N D E R" 

   Thunderstorms occur during every month of the year, however, are more
likely to happen during the spring and summer time when the air is heated
by the sun to extreme temperatures.

   Thunderstorms act like a safety valve in the atmosphere. They are the
results of two different air masses coming together and of the sun heating
the air during the late afternoon and evenings in the summertime.

   Lightning strokes measure in length from a few hundred feet to a few miles
and in thickness from less than an inch to about a foot. The bolt streaks 
through the air and its intense heat causes a sudden and violent
disassociation of air molecules in it path. This results in an increase
in air pressure along the path and causes the vibration which we hear as 
thunder. It is an abrupt explosion from end to end of the lightning path. 
It is so sudden that the surrounding air cannot ease gently away but
if forced, pushed and crowded in waves.

   If lightning strikes quite close, the sound of thunder is a single crack.
The ear is too deafened temporarily by the blast to notice the different
graduations of reverberating thunder from distant portions of the bolt.
Most thunder does not reach the ear as a single crack because of the
speed of which sound travels. A portions of the lightning stroke may be
in the clouds, some six seconds away, another stroke near the earth
only a few seconds away.

   The sound then reaches the ear as a continous rumble. The sound becomes 
more complicated and drawn out rumbles of thunder may develop when certain
differences of air stratification or the pressure of mountains may reflect, 
intensify and reinforce the original sound.

   Thunder is seldom heard over distances of 15 to 18 miles. If the flashes 
occur at high altitudes, it may not produce audible thunder at the ground. 
The distance which the sound of thunder can be heard varies greatly with 
many factors: whether the stroke is cloud to cloud, cloud to earth, or 
open space, the discharge volume, height of the stroke above the earth, 
different air density and any other factor which bears on sound wave
alteration.

   Light from the flash reaches the eye almost instantly. The sound of 
thunder travels at only about 1,000 feet per second. Start counting 
seconds as soon as the lightning flash is seen. Stop when the thunder 
is heard. Multiply the seconds by 1,100. The answer is approximate 
distance in feet to the lightning stroke. By  timing the main flash
from the core of the storm, the direction and movement of the storm
may be determined.

   Lightning flashes move at the speed of light. 186,000 miles 
per second. The Speed of sound is approximately 1,100 per second.

   If you are sitting in left field at a baseball game and the batter 
hits the ball, you see the bat hit the ball, (The Speed Of Light), 
and a nanosecond latter you hear the crack of the bat hitting the ball,
(The Speed Of Sound).



Meteorology         Charles A. Giannetta
                   Meteorologist - Professor

"Thunderstorms"

Thunderstorms generated by temperature imbalances in the atmosphere
are a violent example of convection.

     "Thunderstorms Occur In 3 Stages"

              "1st Stage..."

1st Stage...Cumulus. 2nd Stage...Mature. 3rd Stage...Dissipating

In the first stage (Cumulus) of thunderstorm development an updraft
warms air up to where the water vapor it contains condenses into 
visible droplets and a cloud is formed.

As the clouds form, water vapor changes to liquid and/or frozen cloud
particles. This results in a release of heat, (Latent Heat) that takes
over as the principal source of energy for the developing cloud. As
the cloud particles grow by colliding and combining (Coalescence) with
each other, they may become rain, snow, or hail.

              "2nd Stage "

In the 2nd Stage (Mature) precipitation which has developed falls creating

a downdraft. The cumulonimbus cloud (CB) has now formed. The cloud now
contains an updraft & downdraft.

The thunderstorm may be several miles across its base and often towers

to altitudes 40,000 to 50,000 feet or more and may well reach into the
stratosphere.


               "3rd Stage"

The 3rd Stage. "Dissipating". This stage is marked by a change in wind
flow within the storm cell.

The prevailing updraft which initiated the cloud's growth is now replaced
by the downdraft.

On the ground directly beneath the storm system, this stage is often
accompanied by strong gusts and cold wind from the downdraft, or heavy
precipitation - rain or hail. These downdrafts may well reach over 100
mph and are called (Microbursts or Downbursts)

Lightning always accompanies the thunderstorm. These are nature's
warning that the thunderstorm is in it's most violent stage.

Tornadoes may also be associated with the thunderstorm.

In the 3rd stage, however, the thunderstorm cell has already begun to
die.

The violent downdraft having shared the circulation with the updraft
now strangles it.

Precipitation weakens and the thunderstorm, a short lived creature,
weakens and dies.

From the 1st stage of a thunderstorm to when the storm dies all
takes place in about 30 minutes to an hour.


1. On earth, 2,000+ thunderstorms occur each hour. 40,000 to 50,000
   each 24 hours, most occurring near the equator. Millions and
   millions of lightning strikes each 24 hours

2. Thunderstorms reach up into the stratosphere 50,000 to 60,000 feet.

3. The name given to a thunderstorm is: Cumulonimbus. CB

4. Cumulus meaning puffy. Nimbus meaning rain.

5. The average thunderstorm lasts about 30 minutes to an hour, and
   may or may not be accompanied by hail.




Meteorology         Charles A. Giannetta
                   Meteorologist - Professor

""Thunderstorms & Lightning Safety Rules""

1.  Check to latest weather forecast if you plan to be outdoors.
2.  Listen to NOAA Weather Radio and your local TV and radio stations for the
    latest forecast, bulletins, watches or warnings.
3.  If you hear thunder even off in the distance consider the thunderstorm where
    you are and seek shelter indoors.
4.  Do not use the telephone.
5.  If you are outside, do not stand under any trees or tall objects.
6.  If you are on a golf course move to an indoor shelter.
7.  Get out of a swimming pool and go to an indoor shelter.
8.  If you are playing any type of sports go to an indoor shelter.
9.  Do not stand near a wire fence.
10. Do not take a shower or bath during a thunderstorm.

11. Do not stand near any windows.
12. If you are outdoors farming seek indood shelter.
13. Get away from open water.
14. When fishing, do not seek shelter under trees. Get off the lake and go indoors.
15. Stay off bicycles, motorcycles, golf carts and stay away from metal buildings.
16. Stay away from metal clotheslines any metal pipes and rails or metal objects.
17. If your are with a group of people outdoors move apart, seek indoor shelter.
18. If you are outside with no shelter near by: Do no lie flat on the ground. This
    makes you a larger target for lightning. Should lightning strike nearby the 
    energy can move through the ground and come up to strike you.
18. If the hair on the back of your neck stands on end drop down to your knees and 
    bend forward resting your hands on your knees. Do not lie "FLAT ON THE GROUND."
19. If you are in your automobile get out and seek indoor shelter.
20. If you come across downed electric lines do touch the wires that are down as 
    they maybe still be live with electricity.   
21. Take a course in CPR.  

""First Aid...Call 911"

1.  When people are struck by lightning they usually receive a severe electrical 
    shock and may have severe burns.
2.  If someone has been hit with lightning and appears dead can often times be
    revived by quick action.
3.  When a group of people have been struck by lightning the apparently dead should
    be treated first.
4.  People who are struck and are only stunned also need prompt treatment.
5.  Call 911 immediately.
6.  If you know CPR you can help.



Meteorology         Charles A. Giannetta
                   Meteorologist - Professor

"Severe Thunderstorms"""

1.  Severe Thunderstorm..........Winds more the 57 mph or hail.
2.  Severe Thunderstorm Watch....Severe thunderstorms are possible.
3.  Severe Thunderstorm Warning..Severe thunderstorms have been sighted or
                                 indicated on radar.     
4.  At anyone time about 2,000+ thunderstorms are occurring over the earth.
5.  Lightning strikes the earth about 100 times per second.
6.  About 100,000+ thunderstorms occur over the United States yearly.
7.  About 100+ people are struck and killed a year by lightning in United 
    States with another 250 being injured.
8.  Property damage is in the hunderds of million of dollars.
10. The "National Weather Service" keeps a 24 hour watch across the United States
    for atmospheric conditions which may be cause for issuing Weather Bullitins.
    Severe Thunderstorm Watches and Severe Thunderstorm Warnings. Stay tuned to
    NOAA Weather Radio for the lastest information.

11. Thunderstorms reach up into the stratosphere 50, 000 to 60,000 feet.
12. The average thunderstorm lasts about 30 minutes and goes through 3 stages.
    1. Cumulus Stage.  2. Mature Stage.  3. Dissipating State.
    During the "Mature Stage" the up and down drafts are present. During the
    "Dissipating Stage" only the downdraft is present.

12. The name given to a thunderstorm cloud is: "Cumulonimbus" Symbol "CB"
    "Cumulo meaning Puffy."  "Nimbus meaning Rain."




Meteorology              Charles A. Giannetta
                       Meteorologist - Professor 
 
"Safety Rules For Thunderstorms" 

   The following safety rules should be applied when a
thunderstorms threatens.

   Get inside a home or large building, or inside an 
all-metal (not convertible) vehicle.

   Inside a home, avoid using the telephone except for 
emergencies.

   If outside with no time to reach a safe building or an 
automobile, follow these rules.

   Do not stand underneath a natural lightning rod such as
a tall isolated tree in an open area.

   Avoid projecting above the surrounding landscape, as you
would do if you were standing on a hilltop in an open field,
on the beach or fishing from a small boat.
 
   Get out of and away from open water.

   Get away from tractors and other metal farm equipment.

   Get off of and away from motorcycles, scooters, golf
carts and bicycles. Put down golf clubs.

   Stay away from wire fences, clotheslines, metal pipes,
rails and other metallic paths which could carry lightning
to you from some distance away.

   Avoid standing in small isolated sheds or other small 
structures in open areas.

   In a forest, seek shelter in a low area under thick growth 
of small trees. In the open areas, get to a low place such as
a ravine or valley. Be alert for flash floods.

   If you're hopelessly isolated in a level field or prairie and
you  feel your hair stand on end - indicating lightning is about
to strike - drop to your knees and bend forward putting your hands
on your knees. 

"DO NOT LIE FLAT ON THE GROUND"

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