National Weather Service United States Department of Commerce

Excessive Rainfall and Flooding Threat in the South; Hazardous Heat in the Western U.S. Expanding to the Northern Plains

Multiple rounds of heavy rain and thunderstorms across portions of the Texas and Louisiana Coast will likely lead to flash, urban, small stream and river flooding. An additional heavy rainfall threat will exist from the Lower Mississippi Valley through the southern Mid-Atlantic. Meanwhile, a dangerous heat threat will continue across the Western U.S. and northern Plains through Thursday. Read More >

Current Temperatures



Current Heat Index Temperatures



Current Wet Bulb Globe Temperatures


Max Temperature vs Heat Index


The Heat Index is a measure of how hot it really feels when relative humidity is factored in with the actual air temperature. To find the Heat Index temperature, look at the Heat Index Chart above or check our Heat Index Calculator. As an example, if the air temperature is 96°F and the relative humidity is 65%, the heat index--how hot it feels--is 121°F. The red area without numbers indicates extreme danger. The National Weather Service will initiate alert procedures when the Heat Index is expected to exceed 105°-110°F (depending on local climate) for at least 2 consecutive days.



Compare the Max Temperature and Heat Index


(Prototype -- not official -- availability not guaranteed)

* (Experimental) National WBGT Display *


The Wet Bulb Globe Temperature (WBGT) is a measure of heat stress in direct sunlight, which is based on temperature, humidity, wind speed, sun angle, and cloud cover (solar radiation). This differs from the heat index, which is based only on temperature and humidity and is calculated for shady areas. Scroll down for latest forecasts.




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WBGT vs Heat Index


What's the Difference?


Compare the WBGT and Heat Index


NWS HeatRisk

* (Experimental) National HeatRisk Display *

The NWS HeatRisk is an experimental color-numeric-based index that provides a forecast risk of heat-related impacts to occur over a 24-hour period. HeatRisk takes into consideration:
  • How unusual the heat is for the time of the year
  • The duration of the heat including both daytime and nighttime temperatures
  • If those temperatures pose an elevated risk of heat-related impacts based on data from the CDC
This index is supplementary to official NWS heat products and is meant to provide risk guidance for those decision makers and heat-sensitive populations who need to take actions at levels that may be below current NWS heat product levels.

Category Risk of Heat-Related Impacts
Green
0
Little to no risk from expected heat.
Yellow
1
Minor - This level of heat affects primarily those individuals extremely sensitive to heat, especially when outdoors without effective cooling and/or adequate hydration.
Orange
2
Moderate - This level of heat affects most individuals sensitive to heat, especially those without effective cooling and/or adequate hydration. Impacts possible in some health systems and in heat-sensitive industries.
Red
3
Major - This level of heat affects anyone without effective cooling and/or adequate hydration. Impacts likely in some health systems, heat-sensitive industries and infrastructure.
Magenta
4
Extreme - This level of rare and/or long-duration extreme heat with little to no overnight relief affects anyone without effective cooling and/or adequate hydration. Impacts likely in most health systems, heat-sensitive industries and infrastructure.



Resources


Heat Safety




During extremely hot and humid weather, your body's ability to cool itself is challenged. When the body heats too rapidly to cool itself properly, or when too much fluid or salt is lost through dehydration or sweating, body temperature rises and you or someone you care about may experience a heat-related illness. It is important to know the symptoms of excessive heat exposure and the appropriate responses. The Centers for Disease Control and Prevention (CDC) provides a list of warning signs and symptoms of heat illness, and recommended first aid steps. Some of these symptoms and steps are listed below.

Heat Cramps


Heat cramps may be the first sign of heat-related illness, and may lead to heat exhaustion or stroke.
  • Symptoms: Painful muscle cramps and spasms usually in legs and abdomen and Heavy sweating.
  • First Aid: Apply firm pressure on cramping muscles or gently massage to relieve spasm. Give sips of water unless the person complains of nausea, then stop giving water.

    Seek immediate medical attention if cramps last longer than 1 hour.


Heat Exhaustion


  • Symptoms: Heavy sweating, Weakness or tiredness, cool, pale, clammy skin; fast, weak pulse, muscle cramps, dizziness, nausea or vomiting, headache, fainting,
  • First Aid: Move person to a cooler environment, preferably a well air conditioned room. Loosen clothing. Apply cool, wet cloths or have person sit in a cool bath. Offer sips of water. If person vomits more than once,

    Seek immediate medical attention if the person vomits, symptoms worsen or last longer than 1 hour


Heat Stroke


  • Symptoms: Throbbing headache, confusion, nausea, dizziness, body temperature above 103°F, hot, red, dry or damp skin, rapid and strong pulse, fainting, loss of consciousness.
  • First Aid: Call 911 or get the victim to a hospital immediately. Heat stroke is a severe medical emergency. Delay can be fatal. Move the victim to a cooler, preferably air-conditioned, environment. Reduce body temperature with cool cloths or bath. Use fan if heat index temperatures are below the high 90s. A fan can make you hotter at higher temperatures. Do NOT give fluids.


Resources