LSSN BRIEF SKYWARN

 

 

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!
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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 surroundings)

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 your body.

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.

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A TORNADO WARNING
means that a tornado has been sighted or indicated by weather radar.

YOU MUST TAKE ACTION IMMEDIATELY!
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AT HOME:

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.


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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.


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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 second counts!!!!


Go to the basement or to an inside hallway at the lowest level of the building.

Avoid large, wide places such as auditoriums, cafeterias, large hallways, shopping malls, theaters, and warehouses.

Stay away from glass enclosed areas.


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OUTDOORS:

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.


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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.


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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 KTS)

-Hail 3/4" or larger (a penny is exactly 3/4") report it in inch or coin measurements, not marbles.

-Wall Clouds, Funnel clouds, or Tornadoes

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.

THUNDERSTORMS

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 Texas.:

 

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:

This is 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 mistake:

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
4-Snow thunderstorm
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
16-Light rain
17-Moderate rain
18-Heavy rain
19-Light snow shower
20-Moderate or heavy snow shower

21-Light snow
22-Moderate snow
23-Heavy snow
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
29-Moderate drizzle
30-Heavy drizzle

31-Light hail or ice pellet shower
32-Hail or ice pellet shower
33-Ice crystals
34-Fog
35-Blowing snow, blizzard
36-Blowing sand
37-Rain-snow mixture
38-Lightning
39-Smoke, smog

HAIL

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 KILLER

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 raging water.

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.

Click 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

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.