Risk Level - Legend
None	Limited	Elevated	Significant	Excessive

Note: To display hazard maps, click on any of the risk level indicators below.
Risk	Level						Risk	Level
Tornado							Fog
Hail							Non - Thunderstorm Winds
Thunderstorm Wind Gusts							Excessive Heat
Flooding							Snow and Sleet
Lightning							Ice Accumulation
Spotter Outlook							Frost and Freeze
Fire Weather							Excessive Cold

Risk
	Level
Severe Thunderstorms
Lightning
Flooding
Fire Weather
Fog
Non - Thunderstorm Winds
Excessive Heat
Snow and Sleet
Ice Accumulation
Frost and Freeze
Excessive Cold

 

Hail Risk

Hail is a form of precipitation that occurs when updrafts in thunderstorms carry raindrops upward into extremely cold areas of the atmosphere where they freeze into ice.

How does hail form?

There are two ideas about hail formation. In the past, the prevailing thought was that hailstones grow by colliding with supercooled water drops. Supercooled water will freeze on contact with ice crystals, frozen rain drops, dust or some other nuclei. Thunderstorms that have a strong updraft keep lifting the hailstones up to the top of the cloud where they encounter more supercooled water and continue to grow. The hail falls when the thunderstorm's updraft can no longer support the weight of the ice or the updraft weakens. The stronger the updraft the larger the hailstone can grow.

Recent studies suggest that supercooled water may accumulate on frozen particles near the back-side of the storm as they are pushed forward across and above the updraft by the prevailing winds near the top of the storm. Eventually, the hailstones encounter downdraft air and fall to the ground.

Hailstones grow two ways: by wet growth or dry growth processes. In wet growth, a tiny piece of ice is in an area where the air temperature is below freezing, but not super cold. When the tiny piece of ice collides with a supercooled drop, the water does not freeze on the ice immediately. Instead, liquid water spreads across tumbling hailstones and slowly freezes. Since the process is slow, air bubbles can escape resulting in a layer of clear ice.

Dry growth hailstones grow when the air temperature is well below freezing and the water droplet freezes immediately as it collides with the ice particle. The air bubbles are "frozen" in place, leaving cloudy ice.

Hailstones can have layers like an onion if they travel up and down in an updraft, or they can have few or no layers if they are "balanced" in an updraft. One can tell how many times a hailstone traveled to the top of the storm by counting the layers. Hailstones can begin to melt and then re-freeze together - forming large and very irregularly shaped hail.

How fast does hail fall?

We really only have estimates about the speed hail falls. One estimate is that a 1cm hailstone falls at 9 m/s, and an 8cm stone, weighing .7kg falls at 48 m/s (171 km/h). However, the hailstone is not likely to reach terminal velocity due to friction, collisions with other hailstones or raindrops, wind, the viscosity of the wind, and melting. Also, the formula to calculate terminal velocity is based on the assumption that you are dealing with a perfect sphere. Hail is generally not a perfect sphere!

Estimating Hail Size

Hail size is estimated by comparing it to a known object. Most hail storms are made up of a mix of sizes, and only the very largest hail stones pose serious risk to people caught in the open.

Hailstone size	Measurement		Updraft Speed
	in.	cm.	mph	m/s
bb	< 1/4	< 0.64	< 24	< 11
pea	1/4	0.64	24	11
marble	1/2	1.3	35	16
dime	7/10	1.8	38	17
penny	3/4	1.9	40	18
nickel	7/8	2.2	46	21
quarter	1	2.5	49	22
half dollar	1 1/4	3.2	54	24
walnut	1 1/2	3.8	60	27
golf ball	1 3/4	4.4	64	29
hen egg	2	5.1	69	31
tennis ball	2 1/2	6.4	77	34
baseball	2 3/4	7.0	81	36
tea cup	3	7.6	84	38
grapefruit	4	10.1	98	44
softball	4 1/2	11.4	103	46

 

Understanding Damage and Impacts

Damage from hail approaches $1billion in the US each year. Much of the damage inflicted by hail is to crops. Even relatively small hail can shred plants to ribbons in a matter of minutes. Vehicles, roofs of buildings and homes, and landscaping are the other things most commonly damaged by hail.

Hail has been known to cause injury to humans, and occasionally has been fatal. The most deadly hailstorm on record occurred in India on April 30, 1988, killing 246 people and 1600 domesticated animals.

 

(The above information is from the National Severe Storms Laboratory)

Tornado Risk

Risk Level		Definition
	None	No tornado risk.
	Limited	Probability of a tornado within 25 miles of a point: less than 10 percent.
	Elevated	Probability of a tornado within 25 miles of a point: Equal to or greater than 10 percent.
	Significant	Probability of a tornado within 25 miles of a point: Equal to or greater than 30 percent.
	Extreme	Probability of a  tornado within 25 miles of a point: Equal to or greater than 45 percent.

The probabilities shown are a combination of forecast uncertainty and the magnitude of the threat.

Because of the difficulty in forecasting severe thunderstorms and tornadoes, the trend in the probability is as important as the numbers themselves.

Remember that any probabilities shown in this graphic indicates that forecasters are concerned about a severe weather threat and you should be ready for a warning to be issued in your area sometime during the Day 1 period regardless of how high or low the probability is.

Tornado and Severe Thunderstorm Watches and Warnings ALWAYS take precedence over the information contained in the Risk Analysis Graphics.

What can you do before Severe Weather Strikes?

- Develop a plan for you and your family at home, work, school, and when outdoors.
- Identify a safe place to take shelter.
- Have frequent drills.
- Know the county in which you live or visit.  The National Weather Service in Springfield issues warnings with a reference to county names.
- Keep a highway map nearby to follow storm movement from weather bulletins.
- Have a NOAA Weather Radio with a warning alarm tone and battery back-up to receive warnings.
- Listen to radio and television for weather information.
- Check the weather forecast before leaving for extended periods outdoors.  Watch for signs of approaching storms.
- If severe weather threatens, check on people who are elderly, very young, or physically or mentally disabled.

Tornado Safety Rules

- In a home or building, move to a pre-designed shelter such as a basement.
- If an underground shelter is not available, move to a small interior room or hallway on the lowest floor and get under a sturdy piece of furniture.  Put as many walls as possible between you and the outside.
- Stay away from windows.
- Get out of automobiles.
- Do not try to outrun a tornado in your car; instead leave your car immediately for safe shelter.
- If caught outside or in a vehicle, lie flat in a nearby ditch or depression and cover your head with your hands.
- Be aware of flying debris. Flying debris from tornadoes causes most fatalities and injuries.
- Mobile homes, even if tied down, offer little protection from tornadoes.  You should leave a mobile home and go to the lowest floor of a sturdy nearby building or a storm shelter.

 

Thunderstorm Wind Gust Risk

Damaging wind from thunderstorms is much more common than damage from tornadoes. In fact, many confuse damage produced by "straight-line" winds and often erroneously attribute it to tornadoes. Wind speeds can reach up to 100 mph (161 kph) with a damage path extending many miles.

Downbursts

Downdrafts are generated when rain-cooled, more dense air sinks inside a thunderstorm. Also some of the strong winds aloft are carried down with the downdraft by a process called "momentum transfer". As precipitation begins to fall, it drags some of the air with it. This "precipitation drag" initiates a downdraft. The downdraft is intensified by evaporative cooling as drier air from the edges of the storm mix with the moist air within the storm.

These processes lead to a rapid downward rush of air. As the air impacts the ground it is forced to spread out laterally causing the gusty winds associated with thunderstorms. Occasionally, thunderstorms will produce intense downdrafts that create damage as the wind spread out along the ground.

Downbursts can create hazardous conditions for pilots and these events have been responsible for several disasters.

1. As aircraft descend (right) into the airport they follow an imagery line called the "glide slope" to the runway (solid light blue line).
   
   
2. Upon entering the downburst, the plane encounters a "headwind", an increase in wind speed over the aircraft. The faster wind creates lift causing the plane to rise above the glide slope. To return the plane to the proper position, the pilot lowers the throttle to decrease the plane's speed thereby causing the plane to descend.
   
   
3. As the plane flies to the other side of the downburst, the wind direction shifts and is now from behind the aircraft. This decreases the wind over the wing reducing lift. The plane sinks below the glide slope.
   
   
4. However, the "tailwind" remains strong and even with the pilot applying full throttle trying to increase lift again, there is little, if any, room to recover from the rapid descent causing the plane to crash short of the runway.

Since the discovery of this effect in the early to mid 1980's, pilots are now trained to recognize this event and take appropriate actions to prevent accidents. Also, many airports are now equipped with equipment to detect downbursts and warn aircraft of their location.

Macrobursts and Microbursts

Downbursts are divided into two catagories; macrobursts and microbursts. A macroburst is more than 2½ miles (4 km) in diameter and can produce winds as high as 135 mph (215 kph). Microbursts are smaller and produces winds as high as 170 mph (270 kph).

In wet, humid environments, macrobursts and microbursts will be accompanied by intense rainfall at the ground. If the storm forms in a relatively dry environment, however, the rain may evaporate before it reaches the ground and these downbursts will be without precipitation, known as dry microbursts.

Derechos

A derecho is a widespread and long lived windstorm that is associated with a band of rapidly moving showers or thunderstorms. The word "derecho" is of Spanish origin, and means straight ahead. A derecho is made up of a "family of downburst clusters" and by definition must be at least 240 miles in length.

Derechos are associated with a band of showers or thunderstorms that are often "curved" in shape. These bowed out storms are called "bow echoes". A derecho can be associated with a single bow echo or multiple bow echoes. The bow echoes may vary in scale and may die out and redevelop during the course of derecho evolution.

Winds in derecho can exceed 100 mph. For example, a derecho in northern Wisconsin on July 4, 1977 produced winds of 115 mph. The winds associated with derechos are not constant and may vary considerably along the derecho path.

(information above from NWS Jet Stream Publication)

 

Except for heat related fatalities, more deaths occur from flooding than any other hazard. Why? Most people fail to realize the power of water. For example, six inches of fast-moving flood water can knock you off your feet.

While the number of fatalities can vary dramatically with weather conditions from year to year, the national 30-year average for flood deaths is 127. That compares with a 30-year average of 73 deaths for lightning, 68 for tornadoes and 16 for hurricanes.

National Weather Service data also shows:

• Nearly half of all flash flood fatalities are vehicle-related,
• The majority of victims are males, and
• Flood deaths affect all age groups.

Most flash floods are caused by slow moving thunderstorms, thunderstorms that move repeatedly over the same area or heavy rains from tropical storms and hurricanes. These floods can develop within minutes or hours depending on the intensity and duration of the rain, the topography, soil conditions and ground cover.

Flash floods can roll boulders, tear out trees, destroy buildings and bridges, and scour out new channels. Rapidly rising water can reach heights of 30 feet or more. Furthermore, flash flood-producing rains can also trigger catastrophic mud slides.

Occasionally, floating debris or ice can accumulate at a natural or man-made obstruction and restrict the flow of water. Water held back by the ice jam or debris dam can cause flooding upstream. Subsequent flash flooding can occur downstream if the obstruction should suddenly release.

TURN AROUND, DON'T DROWN^®

Each year, more deaths occur due to flooding than from any other thunderstorm related hazard. Why? The main reason is people underestimate the force and power of water. Many of the deaths occur in automobiles as they are swept downstream. Of these drownings, many are preventable, but foolish people drive around the barriers in place that warn you the road is flooded.

Whether you are driving or walking, if you come to a flooded road, Turn Around...Don't Drown!. You will not know the depth of the water nor will you know the condition of the road under the water.

Of the three deaths which occurred as a result of the Fort Worth tornado, March 28, 2000, one death was due to flooding. The man who drowned was a passenger in a car with his girlfriend, the driver. They approached a low spot with water flowing over the road due to very heavy rain. Flooding is a common occurrence at this location with heavy rains and the danger was well marked.

As the driver drove her car into the water she became frightened as the water rose higher and higher around her vehicle. She backed out to higher ground. The passenger said the water was NOT too deep and he would prove it by walking across to the other side. He never made it.

Follow these safety rules.

• Monitor the NOAA Weather Radio, or your favorite news source for vital weather related information.
• If flooding occurs, get to higher ground. Get out of areas subject to flooding. This includes dips, low spots, canyons, washes etc.
• Avoid already flooded and high velocity flow areas. Do not attempt to cross flowing streams. If you enter a flowing stream and the water gets above you knee, TURN AROUND, DON'T DROWN.
• If driving be aware that the road bed may not be intact under flood waters. Turn around and go another way. NEVER drive through flooded roadways! If your vehicle stalls, leave it immediately and seek higher ground. Rapidly rising water may engulf the vehicle and sweep you and your occupants away.
• Do not camp or park your vehicle along streams and washes, particularly during threatening conditions.
• Be especially cautious at night when it is harder to recognize flood dangers

Lightning Risk

How lightning forms

Lightning results from the buildup and discharge of electrical energy between positively and negatively charged areas. Rising and descending air within a thunderstorm separates these positive and negative charges. Water and ice particles also affect charge distribution.

A cloud-to-ground lightning strike begins as an invisible channel of electrically charged air moving from the cloud toward the ground. When one channel nears an object on the ground, a powerful surge of electricity from the ground moves upward to the clouds and produces the visible lightning strike.

Lightning Safety and Impact Prevention

- Lightning causes an average of 80 fatalities and 300 injuries each year.
- Lightning occurs with ALL thunderstorms, making all thunderstorms dangerous!
- Around 100,000 thunderstorms occur each year in the United States.
- Most lightning fatalities and injuries occur when people are caught outdoors during a thunderstorm.
- The air near a lightning strike is rapidly heated to 50,000 degrees F or hotter than the surface of the sun!  The rapid heating and cooling of the air near the lightning channel causes a shock wave that results in thunder.

30/30 Lightning Safety Rule

Go indoors if, after seeing lightning, you cannot count to 30 before hearing thunder. Stay indoors for 30 minutes after hearing the last clap of thunder.

Other Lightning Safety Rules

- Postpone outdoor activities if thunderstorms are imminent.  This is your best way to avoid being caught in a dangerous situation.
- Move to a sturdy building or car.  Do not take shelter in sheds, under isolated trees, or in convertible automobiles.  Stay away from tall objects such as towers, fences, telephone poles and power lines.
- If lightning is occurring and a sturdy shelter is not available, get inside a hard top automobile and keep the windows up.  Avoid touching any metal.
- Utility lines and metal pipes can conduct electricity. Unplug appliances not necessary for obtaining weather information. Avoid using the telephone or any electrical appliances. Use phones only in an emergency.
- Do not take a bath or shower during a thunderstorm.
- Turn off air conditioners. Power surges from lightning can cause serious damage.

If Caught Outdoors and No Shelter is Nearby...

- Find a low spot away from trees, fences, and poles.  Make sure the place you pick is not subject to flooding.
- If you are in the woods, take shelter under shorter trees.
- If you feel your skin tingle or your hair stand on end, squat low to the ground on the balls of your feet. Place your hands over your ears and your
head between your knees. Make yourself the smallest target possible and minimize your contact with the ground. DO NOT lie down.
- If you are boating or swimming, get to land and find shelter immediately!

Severe Thunderstorm Risk Day 1 risks are covered by individual risks of Tornado, Hail and Thunderstorm Wind Gusts

---

The Severe Thunderstorm risk level is based on the probability of being in a Severe Thunderstorm Warning in an area.

The probability of a Severe Thunderstorm Warning in an area is forecast based on :

• The Probability of Thunderstorms
• The Probability of a Thunderstorm becoming Severe once it has developed (Conditional Probability)

Because of the difficulty in forecasting severe thunderstorms and tornadoes, the trend in the probability is as important as the numbers themselves.

Remember that any probabilities shown in this graphic indicates that forecasters are concerned about a severe weather threat and you should be ready for a warning to be issued in your area sometime during the Day 1 period regardless of how high or low the probability is.

Tornado and Severe Thunderstorm Watches and Warnings ALWAYS take precedence over the information contained in the Enhanced Graphical Hazardous Weather Outlook (HWO) Graphics.

What can you do before Severe Weather Strikes?

- Develop a plan for you and your family at home, work, school, and when outdoors.
- Identify a safe place to take shelter.
- Have frequent drills.
- Know the county in which you live or visit.  The National Weather Service in Springfield issues warnings with a reference to county names.
- Keep a highway map nearby to follow storm movement from weather bulletins.
- Have a NOAA Weather Radio with a warning alarm tone and battery back-up to receive warnings.
- Listen to radio and television for weather information.
- Check the weather forecast before leaving for extended periods outdoors.  Watch for signs of approaching storms.
- If severe weather threatens, check on people who are elderly, very young, or physically or mentally disabled.

A "Severe Thunderstorm" is defined as a thunderstorm that produces a wind speed at or above 58 MPH or, hail 1 inch in diameter or larger.

A Severe Thunderstorm Watch is issued for large area or, state, for a period of time (usually about 6 hours in length) in advance of a projected severe weather event.  This would be on a day when atmospheric conditions favor the development of a number of Severe Thunderstorms. These
watches will likely be followed by Severe Thunderstorm Warnings throughout the life of the watch.

A Severe Thunderstorm Warning is issued for a particular polygon area when a severe thunderstorm is either imminent within that polygon or is occurring in that polygon. A Severe Thunderstorm Warning is not always preceded by a Severe Thunderstorm Watch especially in the Summer-time when thunderstorm development is not as well organized and is more isolated.

 

Risk Level		Definition
	None	Open burning is usually safe with proper containers and precautions under low fire danger conditions.  Residents should always check on local ordinances that prohibit open burning under any conditions.
	Limited	Open burning is usually safe with the proper precautions. Burning should be done in the early morning and late evening to avoid windier and drier conditions from midday through mid-afternoon.  Residents should always check on local ordinances that prohibit open burning under any conditions.
	Elevated	Any open burning is discouraged due to increased wind and lower humidity - except by experienced fire personnel.  Increasing winds and lower humidity contribute to drying fuels. Fires escape control more easily and containment is difficult for inexperienced fire personnel. Approaching Red Flag conditions.
	Significant	Open burning should not be attempted. High winds and extended dry periods lead to extreme burning conditions. Open fires can quickly escape and are very difficult to control, even for experienced fire fighters.  Conditions exceed minimum criteria for a Red Flag Warning in most cases.
	Extreme	Very strong winds, well in excess of Red Flag Criteria combined with moderate to low humidity. Fires will spread very quickly with spot fires common. Fire control is extremely difficult due to very strong winds.

***These definitions are geared towards the general public and general emergency management and should not be confused with the standard National Fire Danger Rating System (NFDRS) adjectives used by wildland fire personnel.

The fire weather category for the Enhanced Hazardous Weather Outlook is based primarily on predicted wind, humidity and temperature, and does not account for fuel moisture from recent precipitation, snow cover and recently melted snow.  Appropriate adjustments to the fire environment must be made.

Fire weather hazard categories will normally be more restricted, generally in the "none" or "limited" categories from May 1st to September 30th due to normally predominant green and moist live vegetation.  This will be subject to change during unusual severe Spring and/or Summer drought.

Spotter Outlook

| Driving | Lightning | Flash Floods | Storm Hazards |

Fog Risk

Atmospheric conditions that are typical for fog development :

• Moist ground or near ground conditions.
• Light winds
• Clear sky

Fog Safety and Impact Prevention

- Most of the Dense fog events in the Missouri Ozarks are from radiation fog which will normally occur on a night with a clear sky, light wind and when the ground is still moist from a recent rain or snow event.
- The air near the ground cools more quickly than the air just above the ground setting up a temperature inversion. If the air temperature cools to the dew point temperature, fog will normally form in light wind and clear sky conditions.

Some Important Safety Notes on Dense Fog

- Remember to drive with your low beam headlights on.  High beams will reflect off of the fog creating a "white wall" effect.
- Allow extra time to get to your destination as travel speeds will likely be much slower than normal.
- In hilly terrain such as the Ozarks, visibilities can change quite rapidly which creates additional driving hazards.  Low lying areas and locations near bodies of water may often times have lower visibilities than surrounding locations.

Driving Safety Tips in High Wind

1) Be aware of the vehicles around you.  High winds are usually more problematic for high profile vehicles such as RV's, trucks, buses, campers and those towing trailers.

2) Reduce your speed and correct your steering, especially when moving from a protected area to an unprotected area, or when meeting large vehicles.

Other Information and Safety Tips for High Wind

Gusts larger than 30 mph can cause lightweight items such as empty trash cans to be blown around and may cause some rough waters on area lakes.  Boaters should use extreme caution.

Gusts larger than 40 mph can cause medium weight objects to be blown around and can create dangerous boating conditions on area lakes.

Gusts larger than 50 mph can cause buildings and trees to become damaged.  Small boats can become capsized.  High profile vehicles can be blown off the road.

 

Excessive Heat Risk
Apparent Temp. (3 hrly) 3    6    9    12    15    18    21    24    27     30    33    36    39    42    45    48

Risk Level		Definition
	None	Maximum Apparent Temperature < 95
	Limited	Maximum Apparent Temperature 95 to 104
	Elevated	Maximum Apparent Temperature 105 to 109 OR Maximum Apparent Temperature greater than or equal to 100 for 4 consecutive days.
	Significant	Maximum Apparent Temperature 110 to 114 OR Maximum Apparent Temperature greater than or equal to 105 for 4 consecutive days.
	Extreme	Maximum Apparent Temperature greater than or equal to 115 OR Maximum Apparent Temperataure greater than or equal to 105 for 5 consecutive days.

Note:	Apparent Temperature is defined as:
		Wind Chill Temperature during the cold season.
		Heat Index Temperature during the warm season.

Heat Wave - A Major Summer Killer

A National Problem

Heat kills by taxing the human body beyond its abilities. In a normal year, about 175 Americans succumb to the demands of summer heat. Among the large continental family of natural hazards, only the cold of winter-not lightning, hurricanes, tornadoes, floods, or earthquakes-takes a greater toll. In the 40-year period from 1936 through 1975, nearly 20,000 people were killed in the United States by the effects of heat and solar radiation. In the disastrous heat wave of 1980, more than 1,250 people died.

And these are the direct casualties. No one can know how many more deaths are advanced by heat wave weather-how many diseased or aging hearts surrender that under better conditions would have continued functioning.

North American summers are hot; most summers see heat waves in one section or another of the United States. East of the Rockies, they tend to combine both high temperature and high humidity although some of the worst have been catastrophically dry.

NOAA’s National Weather Service Heat Index Program

Considering this tragic death toll, the National Weather Service (NWS) has stepped up its efforts to alert more effectively the general public and appropriate authorities to the hazards of heat waves-those prolonged excessive heat/humidity episodes.

Based on the latest research findings, the NWS has devised the “Heat Index” (HI), (sometimes referred to as the “apparent temperature”). The HI, given in degrees F, is an accurate measure of how hot it really feels when relative humidity (RH) is added to the actual air temperature.

To find the HI, look at the Heat Index Chart. As an example, if the air temperature is 95°F (found on the left side of the table) and the RH is 55% (found at the top of the table), the HI-or how hot it really feels-is 110°F. This is at the intersection of the 95° row and the 55% column.

IMPORTANT: Since HI values were devised for shady, light wind conditions, EXPOSURE TO FULL SUNSHINE CAN INCREASE HI VALUES BY UP TO 15°F. Also, STRONG WINDS, PARTICULARLY WITH VERY HOT, DRY AIR, CAN BE EXTREMELY HAZARDOUS.

Heat Index/Heat Disorders: Possible heat disorders for people in higher risk groups.

Heat Index of 130° OR Higher: HEATSTROKE/SUNSTROKE HIGHLY HIGHER LIKELY WITH CONTINUED EXPOSURE,

Heat Index of 105°- 130°: SUNSTROKE, HEAT CRAMPS OR HEAT EXHAUSTION LIKELY, AND HEATSTROKE POSSIBLE WITH PROLONGED EXPOSURE AND/OR PHYSICAL ACTIVITY.

Heat Index of 90°- 105°: SUNSTROKE, HEAT CRAMPS AND HEAT EXHAUSTION POSSIBLE WITH PROLONGED EXPOSURE AND/OR PHYSICAL ACTIVITY.

Heat Index of 80° - 90°: FATIGUE POSSIBLE WITH PROLONGED EXPOSURE AND/OR PHYSICAL ACTIVITY

Note on the HI chart the shaded zone above 105°F. This corresponds to a level of HI that may cause increasingly severe heat disorders with continued exposure and/or physical activity.

The “Heat Index vs. Heat Disorder” table (next to the HI chart) relates ranges of HI with specific disorders, particularly for people in higher risk groups.

Summary of NWS’s Alert Procedures

The NWS will initiate alert procedures when the HI is expected to exceed 105°- 1 10°F (depending on local climate) for at least two consecutive days. The procedures are:

• Include HI values in zone and city forecasts.
• Issue Special Weather Statements and/or Public Information Statements presenting a detailed discussion of
  • Extent of the hazard including HI values
  • Who is most at risk
  • Safety rules for reducing the risk.
• Assist state/local health officials in preparing Civil Emergency Messages in severe heat waves. Meteorological information from Special Weather Statements will be included as well as more detailed medical information, advice, and names and telephone numbers of health officials.
• Release to the media and over NOAA‘s own Weather Radio all of the above information.

How Heat Affects the Body Human

Human bodies dissipate heat by varying the rate and depth of blood circulation, by losing water through the skin and sweat glands, and-as the last extremity is reached-by panting, when blood is heated above 98.6 degrees. The heart begins to pump more blood, blood vessels dilate to accommodate the increased flow, and the bundles of tiny capillaries threading through the upper layers of skin are put into operation. The body’s blood is circulated closer to the skin’s surface, and excess heat drains off into the cooler atmosphere. At the same time, water diffuses through the skin as perspiration. The skin handles about 90 percent of the body’s heat dissipating function.

Sweating, by itself, does nothing to cool the body, unless the water is removed by evaporation, and high relative humidity retards evaporation. The evaporation process itself works this way: the heat energy required to evaporate the sweat is extracted from the body, thereby cooling it. Under conditions of high temperature (above 90 degrees) and high relative humidity, the body is doing everything it can to maintain 98.6 degrees inside. The heart is pumping a torrent of blood through dilated circulatory vessels; the sweat glands are pouring liquid-including essential dissolved chemicals, like sodium and chloride onto the surface of the skin.

Too Much Heat

Heat disorders generally have to do with a reduction or collapse of the body’s ability to shed heat by circulatory changes and sweating, or a chemical (salt) imbalance caused by too much sweating. When heat gain exceeds the level the body can remove, or when the body cannot compensate for fluids and salt lost through perspiration, the temperature of the body’s inner core begins to rise and heat-related illness may develop.

Ranging in severity, heat disorders share one common feature: the individual has overexposed or over exercised for his age and physical condition in the existing thermal environment.

Sunburn, with its ultraviolet radiation burns, can significantly retard the skin’s ability to shed excess heat. Studies indicate that, other things being equal, the severity of heat disorders tend to increase with age-heat cramps in a 17-year-old may be heat exhaustion in someone 40, and heat stroke in a person over 60.

Acclimatization has to do with adjusting sweat-salt concentrations, among other things. The idea is to lose enough water to regulate body temperature, with the least possible chemical disturbance.

Cities Pose Special Hazards

The stagnant atmospheric conditions of the heat wave trap pollutants in urban areas and add the stresses of severe pollution to the already dangerous stresses of hot weather, creating a health problem of undiscovered dimensions. A map of heat-related deaths in St. Louis during 1966, for example, shows a heavier concentration in the crowded alleys and towers of the inner city, where air quality would also be poor during a heat wave.

The high inner-city death rates also can be read as poor access to air-conditioned rooms. While air conditioning may be a luxury in normal times, it can be a lifesaver during heat wave conditions.

The cost of cool air moves steadily higher, adding what appears to be a cruel economic side to heat wave fatalities. Indications from the 1978 Texas heat wave suggest that some elderly people on fixed incomes, many of them in buildings that could not be ventilated without air conditioning, found the cost too high, turned off their units, and ultimately succumbed to the stresses of heat

Preventing Heat-Related Illness

Elderly persons, small children, chronic invalids, those on certain medications or drugs (especially tranquilizers and anticholinergics), and persons with weight and alcohol problems are particularly susceptible to heat reactions, especially during heat waves in areas where a moderate climate usually prevails.

Heat Wave Safety Tips

Slow down. Strenuous activities should be reduced, eliminated, or rescheduled to the coolest time of the day. Individuals at risk should stay in the coolest available place, not necessarily indoors.

Dress for summer. Lightweight light-colored clothing reflects heat and sunlight, and helps your body maintain normal temperatures.

Put less fuel on your inner fires. Foods (like proteins) that increase metabolic heat production also increase water loss.

Drink plenty of water or other non-alcohol fluids. Your body needs water to keep cool. Drink plenty of fluids even if you don’t feel thirsty. Persons who (1) have epilepsy or heart, kidney, or liver disease, (2) are on fluid restrictive diets or (3) have a problem with fluid retention should consult a physician before increasing their consumption of fluids.

Do not drink alcoholic beverages.

Do not take salt tablets unless specified by a physician.

Spend more time in air-conditioned places. Air conditioning in homes and other buildings markedly reduces danger from the heat. If you cannot afford an air conditioner, spending some time each day (during hot weather) in an air conditioned environment affords some protection.

Don’t get too much sun. Sunburn makes the job of heat dissipation that much more difficult

---

Know These Heat Disorder Symptoms

SUNBURN: Redness and pain. In severe cases swelling of skin, blisters, fever, headaches. First Aid: Ointments for mild cases if blisters appear and do not break. If breaking occurs, apply dry sterile dressing. Serious, extensive cases should be seen by physician.

HEAT CRAMPS: Painful spasms usually in muscles of legs and abdomen possible. Heavy sweating. First Aid: Firm pressure on cramping muscles, or gentle massage to relieve spasm. Give sips of water. If nausea occurs, discontinue use.

HEAT EXHAUSTION: Heavy sweating, weakness, skin cold, pale and clammy. Pulse thready. Normal temperature possible. Fainting and vomiting. First Aid: Get victim out of sun. Lay down and loosen clothing. Apply cool, wet cloths. Fan or move victim to air conditioned room. Sips of water. If nausea occurs, discontinue use. If vomiting continues, seek immediate medical attention.

HEAT STROKE (or sunstroke): High body temperature (106° F. or higher). Hot dry skin. Rapid and strong pulse. Possible unconsciousness. First Aid: HEAT STROKE IS A SEVERE MEDICAL EMERGENCY. SUMMON EMERGENCY MEDICAL ASSISTANCE OR GET THE VICTIM TO A HOSPITAL IMMEDIATELY. DELAY CAN BE FATAL. Move the victim to a cooler environment Reduce body temperature with cold bath or sponging. Use extreme caution. Remove clothing, use fans and air conditioners. If temperature rises again, repeat process. Do not give fluids. Persons on salt restrictive diets should consult a physician before increasing their salt intake.

*For more information contact your local American Red Cross Chapter. Ask to enroll in a first aid course.

Produced as a cooperative effort of NOAA’s National Weather Service, the Federal Emergency Management Agency, and the American Red Cross. NOAA/PA 85001

 

Snow and Sleet Risk
Snow/Sleet Forecast (6 hourly) Storm Total 0-36  [0-6]  [6-12]  [12-18]   [18-24]   [24-30]  [30-36]

Heavy Snow
Heavy snow can immobilize a region and paralyze a city, stranding commuters, closing airports, stopping the flow of supplies, and disrupting emergency and medical services. Accumulations of snow can cause roofs to collapse and knock down trees and power lines. Homes and farms may be isolated for days and unprotected livestock may be lost. In the mountains, heavy snow can lead to avalanches. The cost of snow removal, repairing damages, and the loss of business can have severe economic impacts on cities and towns.

An avalanche is a mass of tumbling snow. More than 80 percent of midwinter avalanches are triggered by a rapid accumulation of snow, and 90 percent of those occur within 24 hours of snowfall. An avalanche may reach a mass of a million tons and travel at speeds up to 200 mph.

Injuries Due To Ice and Snow
• About 70% result from vehicle accidents
• About 25% occur in people caught out in a storm
• Most happen to males over 40 years old BLIZZARD: Winds of 35 mph or more with snow and blowing snow reducing visibility to less than ¼ mile for at least 3 hours.

BLOWING SNOW: Wind-driven snow that reduces visibility. Blowing snow may be falling snow and/or snow on the ground picked up by the wind.
SNOW SQUALLS: Brief, intense snow showers accompanied by strong, gusty winds. Accumulation may be significant.
SNOW SHOWERS: Snow falling at varying intensities for brief periods of time. Some accumulation is possible.
SNOW FLURRIES: Light snow falling for short durations with little or no accumulation.

Be Prepared!
Before the Storm Strikes

At Home and Work
Primary concerns are loss of heat, power and telephone service and a shortage of supplies if storm conditions continue for more than a day.

Have available:
- Flashlight and extra batteries.
- Battery-powered NOAA Weather Radio and portable radio to receive emergency information. These may be your only links to the outside.
- Extra food and water. Have high energy food, such as dried fruit, nuts and granola bars, and food requiring no cooking or refrigeration.
- Extra medicine and baby items.
- First-aid supplies.
- Heating fuel. Refuel before you are empty. Fuel carriers may not reach you for days after a winter storm.
- Emergency heat source: fireplace, wood stove, space heater.
       -Use properly to prevent a fire.
       -Ventilate properly.
- Fire extinguisher, smoke alarm. Test smoke alarms once a month to ensure they work properly.
- Make sure pets have plenty of food, water and shelter.

In Vehicles

- Plan your travel and check the latest weather reports to avoid the storm!
- Fully check and winterize your vehicle before the winter season begins.
- Carry a WINTER STORM SURVIVAL KIT:
• Mobile phone, charger, batteries
• Blankets/sleeping bags
• Flashlight with extra batteries
• First-aid kit
• Knife
• High-calorie, non-perishable food
• Extra clothing to keep dry
• Large empty can to use as emergency toilet. Tissues and paper towels for sanitary purposes
• Small can and waterproof matches to melt snow for drinking water
• Sack of sand or cat litter for traction
• Shovel
• Windshield scraper and brush
• Tool kit
• Tow rope
• Battery booster cables
• Water container
• Compass and road maps.
- Keep your gas tank near full to avoid ice in the tank and fuel lines.
- Avoid traveling alone. Let someone know your timetable and primary and alternate routes.

 

Ice Accumulation Risk
Freezing Rain Forecast (6 hr fcst) [Storm Total 0-36]   [0-6]  [6-12]   [12-18]   [18-24]   [24-30]  [30-36]

Freezing Fog: Defined as Fog with temperatures below 32 degrees F. Can cause patchy ice accumulations to develop in exposed surfaces.

Freezing Rain: Rain that freezes when it hits the ground, creating a coating of ice on roads, walkways, trees, and power lines.

Ice Storm Warning: Heavy ice accumulation, generally greater than 1/4 of an inch thick, causing dangerous and damaging situations, such as downed utilitiy lines and icy roads.

Freezing Rain Advisory: Light ice coating on roads and highways, but no damage is expected to trees and power lines.

Have a winter storm survival kit in your home and vehicles, and be sure to receive the latest weather information from the NWS.

Be aware of carbon monoxide poisoning.  Never use generators, grills, camp stoves, or other gasoline, propane, natural gas, or charcoal-burning devices inside your home, basement, garage, or camper-- or event outside near an open window.

Frost and Freeze Risk

Additional Frost and Freeze Information

The National Weather Service in Springfield, MO will issue Frost Advisories and Freeze Warnings for the growing season.  These products will be issued during the time frame of April 1st through November 15th.

Frost Advisories may be suspended earlier in the Autumn based on seasonal trends and surrounding Weather Service Office collaboration.

A freeze watch may also be issued for significant or unexpected freeze events generally in the Spring.  This product would typically be issued 24 to 48 hours in advance of the freeze and would be replaced with a Freeze Warning.

The average date of the last killing frost in Spring is April 13th.

The average date of the first killing frost in Autumn is October 25th.

 

Coastal Flooding Risk

Rip Currents Risk

 

High Surf Risk

Risk Level		Definition
	None	No High Surf Risk.
	Limited
	Elevated
	Significant
	Extreme

Marine Hazard Risk

Excessive Cold Risk
Apparent Temp. (3 hrly) 3    6   9   12   15   18   21   24    27    30   33   36   39   42   45   48

Risk Level		Definition
	None	Minimum apparent temperature greater than or equal to 10 degrees F.
	Limited	Minimum apparent temperature -9 to 9 deg F.
	Elevated	Minimum apparent temperature -10 to -24 deg. F
	Significant	Minimum apparent temperature -25 to -34 deg. F.
	Extreme	Minimum apparent temperature less than or equal to -35 degrees F

Note:	Apparent Temperature is defined as:
		Wind Chill Temperature during the cold season.
		Heat Index Temperature during the warm season.

Extreme Cold

 

Extreme cold often accompanies a winter storm or is left in its wake. Prolonged exposure to the cold can cause frostbite or hypothermia and become life-threatening. Infants and elderly people are most susceptible. What constitutes extreme cold and its effect varies across different areas of the United States. In areas unaccustomed to winter weather, near freezing temperatures are considered "extreme cold." Freezing temperatures can cause severe damage to citrus fruit crops and other vegetation. Pipes may freeze and burst in homes that are poorly insulated or without heat. In the north, below zero temperatures may be considered as "extreme cold."

FROSTBITE

 

Frostbite is damage to body tissue caused by that tissue being frozen. Frostbite causes a loss of feeling and a white or pale appearance in extremities, such as fingers, toes, ear lobes, or the tip of the nose. If symptoms are detected, get medical help immediately! If you must wait for help, slowly rewarm affected areas. However, if the person is also showing signs of hypothermia, warm the body core before the extremities.

HYPOTHERMIA: LOW BODY TEMPERATURE

Warning signs - uncontrollable shivering, memory loss, disorientation, incoherence, slurred speech,drowsiness, and apparent exhaustion.

Detection - Take the person's temperature. If below 95F (35C),immediately seek medical care! If medical care is not available, begin warming the person slowly. Warm the body core first. If needed, use your own body heat to help. Get the person into dry clothing, and wrap them in a warm blanket covering the head and neck. Do not give the person alcohol, drugs, coffee, or any hot beverage or food; warm broth is better. Do not warm extremities (arms and legs) first! This drives the cold blood toward the heart and can lead to heart failure.

WIND CHILL

The wind chill is based on the rate of heat loss from exposed skin caused by combined effects of wind and cold. As the wind increases, heat is carried away from the body at an accelerated rate, driving down the body temperature. Animals are also affected by wind chill.

Radar & Satellite Links	Radar Analysis			Satellite Analysis
	Springfield	North Central Regional	South Central Regional	Visible	Infared	Water Vapor

Understanding the anticipated risk of weather hazards is important to making daily plans as well as carrying out preparedness activities prior to a hazardous weather event. The Enhanced Hazardous Weather Outlook (EHWO) depicts the risk of potential weather hazards through day 7 utilizing text, alert buttons and graphics.  The EHWO should be utilized as a preparedness tool prior for hazardous weather events and a means of monitoring the severity and coverage during a hazardous weather event.

The Enhanced Hazardous Weather Outlook (EHWO) provides:

The EWHO integrates the text of the Hazardous Weather Outlook with the graphical representation of expected hazards.  The graphical buttons depict the threat level for a given day.  The button display provides a quick overview of potential hazard risk levels through day 7.  More specific information about expected hazards can be obtained by clicking on the buttons. Additional links to radar, briefings pages, etc, are provided to compliment the hazards graphics.

Each days graphic represents a time frame from 12 UTC to 12 UTC which is 6 am current day to 6 am next day during standard time, and 7 am current day to 7 am next day during daylight savings time.

This section will describe how to navigate through our Enhanced Hazardous Weather Outlook(HWO) suite of pages.

000
FLUS43 KSGF 231005
HWOSGF

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SPRINGFIELD MO
505 AM CDT THU MAY 23 2013

KSZ073-097-101-MOZ055>058-066>071-077>083-088>098-101>106-241015-
BOURBON-CRAWFORD-CHEROKEE-BENTON-MORGAN-MILLER-MARIES-VERNON-
ST. CLAIR-HICKORY-CAMDEN-PULASKI-PHELPS-BARTON-CEDAR-POLK-DALLAS-
LACLEDE-TEXAS-DENT-JASPER-DADE-GREENE-WEBSTER-WRIGHT-NEWTON-
LAWRENCE-CHRISTIAN-DOUGLAS-HOWELL-SHANNON-MCDONALD-BARRY-STONE-
TANEY-OZARK-OREGON-
505 AM CDT THU MAY 23 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF THE MISSOURI
OZARKS AND EXTREME SOUTHEAST KANSAS.

.DAY ONE...TODAY AND TONIGHT.

WEATHER HAZARDS EXPECTED...

  LIMITED LIGHTNING RISK.

DISCUSSION...

  THERE IS A SLIGHT CHANCE FOR A THUNDERSTORM LATE TONIGHT
  ACROSS PORTIONS OF EXTREME SOUTHEASTERN KANSAS AND FAR
  SOUTHWESTERN MISSOURI...GENERALLY WEST OF A GIRARD KANSAS TO
  ANDERSON MISSOURI LINE. THE MAIN IMPACT FROM ANY STORMS WOULD
  BE OCCASIONAL LIGHTNING STRIKES.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

  THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS ON FRIDAY ACROSS
  EXTREME SOUTHEASTERN KANSAS AND WESTERN MISSOURI. MULTIPLE
  ROUNDS OF SHOWERS AND THUNDERSTORMS ARE THEN EXPECTED FROM
  THIS WEEKEND INTO EARLY NEXT WEEK.

  SUSTAINED SOUTHERLY WINDS AROUND 20 MPH WITH GUSTS TO 30 MPH
  ARE EXPECTED SATURDAY ACROSS EXTREME SOUTHEASTERN KANSAS.

.SPOTTER INFORMATION STATEMENT...

  SPOTTER ACTIVATION WILL NOT BE NEEDED THROUGH TONIGHT.

&&

THIS PRODUCT IS NOW AVAILABLE IN GRAPHICAL FORMAT...ALONG WITH
OTHER WEATHER...HYDROLOGICAL AND CLIMATE INFORMATION...AT
HTTP://WWW.CRH.NOAA.GOV/SGF(ALL LOWERCASE)

$$

SCHAUMANN