The following is a brief version of Skywarn training that I have
put together for a reference.
The SKYWARN spotter network is a vital element in the nation's
ability to react to dangerous and threatening weather. Spotters
are a crucial front-line part of the Weather Service's storm warning
program; they provide up-to-the-minute reports on developing storms
and for confirming reports on storms that appear threatening. Most
importantly, spotters' reports help give communities a first line
of defense against hazardous weather.
It does not overstate the importance of spotter reports to say that
the weather safety of the U.S. public rests on the quality and timeliness
of those ground truth reports. While there have been important strides
in storm detection technology, ground truth observations remain
crucial to effective storm warnings. And while the scientific understanding
of storm structure has grown, on-the-spot observations remain at
the heart of continuing to increase that body of knowledge. Spotters
are the eyes and ears of the National Weather Service.
Please keep in mind as you read this page, that
we are overdue for a major event. The following is from NWS. We
can expect another of these events anytime.
Question is.......ARE YOU READY?
9. MAY 27...1997 - THE JARRELL TORNADO...A RARE F5 TORNADO...CUT
ACROSS JARRELL...TEXAS LEVELING THE AREA IN ITS PATH.
IT KILLED 27 PERSONS IN JARRELL...1 IN CEDER PARK AND
1 IN PERDENALES VALLEY. THE SYSTEM SPAWNED WIDESPREAD
SEVERE WEATHER WITH HAIL...DAMAGING WINDS...AND
FLASH FLOODING ACROSS MOST OF SOUTH CENTRAL TEXAS.
10. OCTOBER 17 - 18...1998 - TORRENTIAL RAINS FROM TRAVIS COUNTY
SOUTHWARD PRODUCED DAMAGING FLOODS IN ONION CREEK...
THE COLORADO...SAN MARCOS...GUADALUPE...AND SAN ANTONIO
RIVERS. LESSER FLOODING OCCURRED UPSTREAM OF THE
HILL COUNTRY DAMS. A 35 INCH RAINFALL CENTER OCCURRED
A COUPLE OF MILES SOUTHEAST OF SAN MARCOS.
THIRTY ONE PERSONS LOST THEIR LIVES WITH THIS EVENT.
As we all know, Texas weather can change in minutes. Even the Storm
Prediction Centers forecasts for Texas are hit or miss at best.
There are many variables which come into play in this state. From
the clashes of different occurrences of moving weather from different
directions, to the range of terrains we have, varying from mountains,
to plains, to escarpments, all these things cause our weather to
do odd things with usually little notice, though there are some
patterns if you pay close attention.
For the most part though, we can have severe weather blow up with
little to no notice, so it is vital that we as weather watchers
pay close attention during our severe season, which is mainly April,
May, and June, with a slight second season in October, November,
and even December, during the Hurricane months.
A SEVERE THUNDERSTORM WARNING
means that a severe thunderstorm is occurring or is just about to
move into your area.
You must take action immediately!
If you are outdoors, get inside. Find safe shelter in a building
or hard top car.
If you are in the water, get out! Get off the beach!
If you are boating get to land and find safe shelter immediately!
What if there is no safe shelter nearby?
Find a low-lying, open place away from trees, poles, or metal objects.
Make sure the place you pick is not subject to flooding. Don't seek
shelter under a large tree that stands alone. If you are in the
woods, you can take shelter under a group of shorter trees.
Don't stand on a hilltop (you do not want to be higher than your
Don't huddle close together in groups, lightning can easily pass
from one person to the next.
Don't hold on to anything metal. Get rid of any metal objects on
Make yourself the smallest target possible.
Squat low to the ground on the balls of your feet and place your
hands on your knees with your head between them. Do not lie flat
on the ground! This will make you a larger target and increase your
contact with the wet ground.
Stay tuned to your local WeatherNet TV station, NOAA Weather Radio
or other media for the latest information.
A TORNADO WARNING
means that a tornado has been sighted or indicated by weather radar.
YOU MUST TAKE ACTION IMMEDIATELY!
Go immediately to the lowest level of the house such as a basement
or storm cellar. If there is no basement, go to an interior hallway
or room without windows, such as a bathroom or closet.
Get away from windows ! (It is not true that opening windows will
reduce damage to your home.) Stay in the center of the home.
Protect yourself from flying or falling debris. Get under a stairwell
or in a central closet or bathroom. Bathrooms are well known for
surviving tornadic winds, mainly due to the plumbing running into
the foundation. Mainly, you want to be in a central room, with as
many walls as possible between you and the outside and windows.
If possible cover yourself with a rug, mattress or blanket. Otherwise,
use your arms to protect your head and neck.
IN A MOBILE HOME:
Mobile homes are particularly susceptible to tornado damage. Leave
your mobile home immediately and seek shelter in a neighboring frame
home or a storm shelter. (You are actually safer lying in a ditch,
exposed to the elements, than you are remaining in a mobile home.
They can blow over or disintegrate in as little as 70 mph winds,
depending on the age and quality of the home. None will withstand
much over 100 mph winds.)
If shelter is not available, lie in a ditch or low-lying area a
safe distance away from the mobile home. Use your arms to protect
your head and neck from debris.
IN A HIGH RISE BUILDING:
There may not be enough time to get to the basement or storm shelter.
In this case, interior rooms and halls are the best locations in
large buildings. Central stairwells are safe locations as well.
Do not attempt to use the elevators.
Stay away from glass walls and windows.
AT SCHOOL, WORK or PUBLIC PLACES:
Your school or workplace should already have an approved tornado
safety plan for you to follow. If not then a plan needs to be developed!!
Having a plan and following it can save time and lives!!! Every
Go to the basement or to an inside hallway at the lowest level of
Avoid large, wide places such as auditoriums, cafeterias, large
hallways, shopping malls, theaters, and warehouses.
Stay away from glass enclosed areas.
Get inside a building if you can.
If shelter is not available or if there is no time to get indoors,
lie in a ditch or low-lying area or crouch near a strong
building. Be aware of the potential for flooding. Use your arms
to protect your head and neck from debris.
IN A VEHICLE:
Never try to outdrive a tornado in a car or truck.
Get out of the car immediately and take shelter in a nearby building.
If there is no time to get indoors, lie in a ditch or low-lying
area away from the vehicle. Be aware of the potential for flooding.
Protect your head and neck from debris with your arms.
Stay tuned to your local WeatherNet TV station, NOAA Weather Radio
or other media for the latest information.
First of all, lets clarify
the severe weather reporting criteria:
(These are the most basic elements of
weather reporting, and anyone who has had a Skywarn class, or claims
to be involved with a Skywarn group should know these by heart.
Try to memorize them.)
-Rainfall rate in excess of
2" per hour
-Winds in excess of 58 MPH (50
-Hail 3/4" or larger (a
penny is exactly 3/4") report it in inch or coin measurements,
-Wall Clouds, Funnel clouds,
IN AN ACTIVE WX NET, DO NOT REPORT
ANYTHING BELOW THIS CRITERIA UNLESS REQUESTED TO DO SO BY NET CONTROL.
KEEP THE FREQUENCY OPEN FOR EMERGENCY AND PRIORITY TRAFFIC, PEOPLES
LIVES ARE AT RISK.
There are several types of Thunderstorms for our area. Squall lines-associated
with fronts, "Popcorn variety cells that pop up out of nowhere
along a frontal boundary, and then occassionally we get Supercells.
These usually form on their own and become raging machines as there
is no rain or interference around the South and East sides to occlude
their fuel=warm air and moisture. These cells can cover an area
as large as 2000 square miles and travel as fast as 70 mph for hours.
These are the ones of main concern, as they will produce the damaging
winds, outflows/gust fronts in excess of 70 mph, microbursts with
winds in excess of 150 mph, very large hail, and tornadoes. The
squall lines are also an issue here too. They can produce supercells
on the Southern end of the line where the fuel is, or in breaks
in the squall line where they can get good inflow, uncooled by the
advancing rain. Alot of them become Derechos also. A Derecho is
when the squall line gets a boost from winds and begins to bow out
along the middle of the line mostly, forming a bow shape like so-
) (a bow) usually moving from West to East. The center of the bow
will have much faster winds, but is usually short lived as it pushes
itself out to the point it seperates from the line and loses its
backing. The "popcorn" variety of cells are usually harmless
if they dont grow into anything. They just come and go kind of like
fireworks in the sky, appearing for a short burst, then fading out.
Cloud formations will give a good clue as to what you will see.
This is a cumulonimbus cloud, with a shearing anvil, moving towards
the camera. This is a large thunderstorm aerial shot from probably
30-40,000 feet up. Note that from the ground, you wont see much
of this, but if you see this formation from a distance, keep an
eye on it. See the little plumes in center of pic going up underneath
the anvil? That is the leading edge of the storm. This is where
the fuel is coming in and feeding the "machine":
They will gradually go higher and get overtaken by the main tower,
and new ones will rise up, thus, a machine, repeating this cycle.
Here is an explanation of this process:
Also you will notice the flat top of the anvil. This is our cap,
where the atmosphere is stopping the upward build of the cell. The
cap may erode away, and with the cycle, the leading towers can generate
higher, eventually punching through the cap with enough lift, thus
making the storm stronger. The Jarrell cell came into an area of
no cap and topped out at 58,000 feet.
SUPERCELLS & TORNADOES
(If you are suffering from "Supercell
Deprivation", as I am, you
must read this page, it's great)
This is a classic HP Supercell (high precipitation) taken by Warren
Faidley (with permission.) Odds are, unless you are in the Panhandle,
you will never see a nice a view as this. This is however, a great
example of a Supercell. Note the size of the cell in comparison
to the tornado. This is only the bottom portion of the cell, so
you can just imagine the size of this thing. It's also out there
all by itself, with the rain shearing out of it to the right, it
has plenty of open, unobstructed area to continue to be a raging
machine. It is out there on the open plains, with unobstructed view,
just spinning around like a giant balloon. Again, unfortunately,
we will never see this clear of a shot at any formation in Central
This is a shot of what the HP would look like from a distance.
If you're lucky, you would see this, but once you get close to it,
you won't see much in the way of formation:
This is a classic shot of an LP Supercell (Low Precip). You dont
see these very often, and they usually don't produce tornadoes,
but they can:
This is a couple of examples of your standard wall cloud. Remember,
watch it for a minute and see if it is rotating if you're close
enough. False reports that are turned in look bad on everyone:
a screen capture from Sat. 3/27 in Oklahoma. Note the hook, and
then the cut out of the storm attributes below it:
Note the distinctions on the first line, which is this storm. A
TVS (Tornadic Vortex Signature) at a range of 51 miles from the
radar, 100% probability of severe hail , and the hail size-4.00".
This is not something you see everyday, though it is common with
a good tornado. VIL's of 63, a 72 dbz reflection to the radar, the
height at the radar beam sweep20,100, the top height in the beam
sweep-39,600 feet, and it is moving ENE (247 degrees) at 25 mph.
This is a phone pic from the guy that was there chasing this one,
showing the underside of the supercell. He was having difficulty
getting a decent shot with the phone due to no zoom, lighting, etc.
This couldn't be complete without including the "Dead Man
Walking" pic from Jarrell. Indian legend has it that if you
see the dead man walking, you are about to die. Unfortunately, such
was the case for 27 people in Jarrell that afternoon.
Don't be fooled by look alikes either. As you can see, these would
fool the best. It helps to watch them for a few minutes before announcing
a tornado, Again, another unwanted false report, though an honest
And always remember, Tornadoes are nothing to take lightly, whether
at home, or mobile:
Below are some map symbols used in weather charts:
1-Tornado, funnel cloud
2-Thunderstorm in area (no rain at station)
3-Thunderstorm with rain
5-Thunderstorm with freezing rain
6-Thunderstorm with hail or ice
7-Severe thunderstorm in area (no rain at station)
8-Severe thunderstorm with rain
9-Severe snow thunderstorm
10-Severe thunderstorm with freezing rain
11-Severe thunderstorm with hail or ice
12-Moderate or heavy freezing rain
13-Light freezing rain
14-Moderate or heavy rain shower
15-Light rain shower
19-Light snow shower
20-Moderate or heavy snow shower
24-Light hail or ice pellets
25-Moderate or heavy hail or ice pellets
26-Moderate or heavy freezing drizzle
27-Light freezing drizzle
28-Light drizzle, mist
31-Light hail or ice pellet shower
32-Hail or ice pellet shower
35-Blowing snow, blizzard
ESTIMATING HAIL SIZE VISUALLY:
Pea size - 1/4-1/2 inch
Penny size - 3/4 inch
Quarter size - 1 inch
Half Dollar size - 1 1/4 inch
Silver Dollar size - 1 1/2 inch
Pool/Billiard ball - 2 inch
Tennis Ball size - 2 1/2 inch
Baseball size - 2 3/4 inch
Softball size - 4 inch
Grapefruit size - 5 inch
On April 28, 1992, a severe thunderstorm outbreak rumbled across
southern Oklahoma and through North Central Texas, producing a swath
of hail damage in one of the costliest severe weather events ever
for the region. Hail up to 4.5 inches in diameter was recorded during
the event, which lasted several hours and ultimately resulted in
losses of over $750 million.
On May 5, 1995, a devastating supercell produced softball-sized
hail in Tarrant County, accompanied by flash flooding and high winds.
Over a hundred people, most of which were attending the outdoor
Mayfest celebration in downtown Fort Worth, were injured. Insured
damage reached nearly $1.1 billion, making it one of the insurance
industry's most expensive thunderstorms in history.
FLASH FLOODING-TEXAS' #1
OK, the highest risk in Texas is Flash Flooding. It kills more
people in Texas than all other weather related events combined.
Mainly because people are impatient or just stubborn. It's kind
of like relating it to trying to beat a train, it's just a bad idea,
if you lose, it's usually final. If you cant see the pavemant under
the water, it may not be there. It may be a 10 foot deep hole of
If you have ever hydroplaned on the road, it is the same effect,
except that the water is moving instead of you, and your car will
float once it gets enough moving water under the tires:
Would you drive across this flooded crossing?
You may end up like this seconds later. Remember, the road may
not be under the water as it looks.
Texas is prone to frequent, intense storms that can produce tremendous
amounts of rain. In 1981, the Memorial Day Flood killed
13 after 10 of rain fell in four hours. In November 1974,
a cold front dropped between four and ten inches of rain in central
Texas resulting in the death of another 13. In June 1935, 22
of rain fell in three hours leaving 3000 Austin residents homeless.
The 1921 Great Thrall/Taylor Storm still holds the record
as the greatest of all continental U.S. rainstorms during 18 consecutive
hours. 23.11 fell within 24 hours at Taylor; 36 fell
in Thrall within 18 hours . . . 40 of rain in total. 224 people
perished during this storm. Other great storms in 1915, 1900, and
1869 produced tremendous property damage and loss of life.
Here for more Central Texas flooding history.
Here is a shot of Shoal Creek the day after the Memorial Day Flood
of 1981. I was out in this event all night, and flooded out my vehicle
3 different times (2 seperate vehicles). I was VERY lucky. It rained
so hard, so fast that streets became 1-2 foot deep in 5-10 minutes.
Shoal Creek had dammed up at a bridge at 30th street and Lamar,
with trees and such, and eventually broke loose, sending a tidal
wave as high as the street lights (30 feet) down Lamar Blvd. One
person was found clinging to the top of a light pole. 13 people
died that night, some were never found. The flooding started in
North Austin on Shoal Creek, North of Anderson Ln. and grew as it
went. Over 3000 homes were destroyed. The caption for the above
pic says that a dealership (Ford) lost 500 vehicles out of their
parking lot. (yes, 500, remember-30 foot wall of water)
Below is an aerial shot of the Congress bridge in Austin in 1935,
before the Mansfield dam was built. But, you would be surprised
to know that there have been times when this could happen again.
LCRA themselves stated that if the 26-32 inches of rain from the
flood of 1998 that flooded San Marcos, New Braunfels, and downstream,
would have fallen over the Highland lakes to the North, instead
of where it did, 5 of the 8 existing dams would have been overtopped
and at risk of failing. This photo shows just
the lack of Mansfield dam. You could not imagine what this view
would be if several dams failed and collapsed. MANY people would
die and probably never be found, as the flood would continue all
the way down to the coast, taking many more lives all the way down.
Granted, this is an extreme example. Though the rains were 50 miles
away from causing that scenario to occur. It can happen!
Congress Bridge looking North:
This is a shot of the 281 bridge at Johnson City after another
flood on the Pedernales river, not dam controlled. Can you imagine
encountering this at night? This is a US highway, not a farm road:
Lightning is also a high risk while out spotting. Many people are
struck by lightning each year. It can strike up to 15 miles out
of a cell. It can strike phone lines and zap you inside home. It
has even struck a speaker at a drive thru bank, coming inside and
hitting the teller. It can also hit your radio antenna on your vehicle.
There are millions of lightning pics out there, and we all know
what they look like. I wanted to post this pic as it is probably
the most awesome lightning pic ever taken. A farmer coming in his
driveway snapped it from his truck. The Sycamore tree is 60 feet
tall. Also notice the step leader coming up from the TV antenna.
It didn't connect, but could still kill. It did fry his TV:
I will add to this shortly, but want to go ahead and get it posted.
Check back here frequently, until I declare it done.