On the same day, 91-degree high temperatures were recorded in Topeka, Kansas, and the heat advisory past rumored.
Yes, but each National Weather Service (NWS) office has different criteria for heat warnings and excessive heat warnings that take into account the topography, climatology, and potential effects of urban heat islands.
For example, Miami is really hot on Tuesday but doesn’t meet the technical requirements for hot advisors or warnings.
To receive heat advisory, Miami must have a heat index value of 108 degrees or higher for at least two hours. For excessive heat warnings, the heat index must reach 113 degrees or higher for at least two hours.
National Weather Service the word heat adviser means people can get heat if they don’t take precautions. An excessive heat warning means that people can be “seriously” affected
The heat index is a measure of how hot it feels to your body when you take into account the relative humidity and actual air temperature. One limiting factor, however, is that the heat index is calculated in shady locations, not direct sunlight,
which can feel 15 degrees warmer.
Florida breeze
Tyler Mauldin, a CNN meteorologist who has worked in Florida for nearly 10 years, explained that sea winds play an important role in temperature variability throughout the Sunshine State.
“Florida’s weather is very much influenced by the direction of the wind,” he said. “The offshore wind is a very hot wind for Miami, which is exactly the same as ours. It prevents colder air from entering the Atlantic. Add dry air with dewdrops in the 60s, and that’s a recipe for dangerous temperatures. “
Miami has not only had one hot day this year, but intense hot weeks. In fact, seven of the 10 hottest weeks recorded have happened this year – and Miami’s high temperatures did not peak traditionally until early August.
The criteria for overheating vary
Based on
Iowa Environmental Mesonet, which collects environmental data from cooperating members, has been more than two years since Columbia, South Carolina, issued a hot advisor, but Minneapolis has had four in the past week.
Once again, everything boils down to different criteria. In Colombia, the heat index must reach at least 110 degrees to get a heat advisory. In Minneapolis, a heat advisory is issued when the heat index reaches 95 degrees.
Another criterion used by some National Weather Service offices, such as the one in Minneapolis, is a measurement called a world light bulb thermometer.
The military has used this tool for decades. The wet bulb thermometer factors are more detailed such as sun angle, cloud cover and wind speed. It’s very important to know if you are outside doing any type of heavy work, exercising or monitoring teen sporting events.
In Minneapolis, the criteria for heat advisory is a heat index value of 95 degrees or a reading of the world light bulb of 86 degrees.
Philadelphia has its own hot bubbles
Philadelphia has its own guidelines called the Kalkstein Procedure.
Back in 1997, the NWS office in Philadelphia partnered with researcher Dr. Laurence Kalkstein from the University of Miami
come up with new criteria to issue hot warnings in this region.
Simply put, their study concluded that the heat and humidity levels below the criteria that triggered the suggestion to cause harmful effects in urban locations due to the presence of widespread asphalt and population density.
The NWS Philadelphia Office not only uses different criteria for urban and rural locations, but they also break it down separately during the year.
Why? Well, people might not be accustomed to a 90 degree day on April 1 but it might be on July 20.
For the urban areas of Philadelphia, Trenton and Wilmington, the following criteria are used:
From May 1 to June 15, a heat index of 96 to 104 degrees is expected.
From June 16 to June 30, a heat index of 98 to 104 degrees is expected.
From July 1 to September 30, a heat index of 100 to 104 degrees is expected.
In the Delmarva and southern New Jersey regions, the threshold is a heat index reading of 105 degrees or higher for at least two hours. Everywhere in the area around Philadelphia, the threshold is 100 degrees or higher for at least two hours.
Dry heat is different
The criteria change again in the southwestern desert.
Because it’s so hot for most of the year in the desert, the NWS office in the Southwest doesn’t issue hot advice, just a warning of excessive heat.
This heat warning has more flexible criteria than in the East, and is in a
level based system. Level 1 (yellow) is the lowest, and level 4 (magenta) is the highest. For an area to have excessive heat warnings there must be a widespread level 3 (red), with a little level 4 “sprinkled.”
The Las Vegas NWS office reported weather for the highest and lowest altitude points in the US – Mount Whitney and adjacent Badwater Basin in Death Valley, respectively, said Jenn Varian, meteorologist at the office.
“Death Valley regularly exceeds 115 degrees in the summer but areas like Mount Whitney don’t,” Varian said. “So altitude, terrain types in the West and even throughout the year play a major role in how we issue this overheating warning.”
Some southwest NWS offices also take into account the number of tourists coming to the city and temporary populations who are not accustomed to extreme desert heat.
Security is key
The point is how best to protect people from various heat-related illnesses, including heat cramps, fatigue and strokes. This advice and warning serve as a guide to reflect the possibility of certain heat-related illnesses and even the possibility of death from heat exhaustion.