Heat dome continues to raise temps across South and Midwest, will begin to move into Northeast

Yahoo

3 days ago

The 'heat dome' that has hovered over tens of millions of people in the South and Midwest this week is now spreading into parts of the Northeast on Thursday, according to the Weather Channel.
A heat dome is a high-pressure bubble in the upper levels of the atmosphere that traps hot air and sun radiation underneath it. The Climate Reality Project, a nonprofit focused on climate change advocacy and education, compares heat domes to putting a lid on a hot pot; the lid keeps the hot air from leaving the pot and keeps the contents of the pot hot for a longer time.
While late July usually is the hottest time of the year for most of the U.S., AccuWeather reports these temperatures will be 5 to 15 degrees Fahrenheit higher than the historical average.
An 'Extreme Heat Watch' advisory alert, which warns 'dangerous heat is possible,' was issued for West Virginia on Thursday. An 'Extreme Heat Warning' alert, which warns 'dangerous heat is happening or about to happen,' was sent to areas in Illinois, Missouri, Mississippi, Arkansas, Louisiana, Kentucky, Tennessee, New Jersey, Delaware, Pennsylvania and New York on Wednesday.
Some of these extreme heat warnings were sent to major cities like Boston, Detroit, New York City and Washington, D.C., where temperatures will reach the mid-90s by Friday, the Weather Channel reported. However, temperatures in these areas are expected to drop over the weekend.
Parts of the Midwest and the South will still be in temperatures near or above 100 degrees through the rest of the weekend, and potentially into the middle of next week.
Florida, which has been experiencing hot and muggy conditions across the state all week, will continue to experience high temperatures in the upper 80s to lower 90s on Thursday and Friday, according to Florida Disaster, a division of the state's Department of Emergency Management. The state's heat index values will be particularly high on the western side of the Florida Panhandle, compared to the rest of the state. (The National Weather Service (NWS) 'heat index' is a calculator that estimates what outdoor temperatures feel like to the human body.)
Experts cannot determine exactly when the heat dome will end. Heat domes take a long time to break down, Bryan Jackson, a meteorologist at the NWS's Weather Prediction Center, told Scientific American, so the extreme heat is expected to last through the rest of the week for some areas.
'Corn sweat' drives up humidity in the Midwest
As heat index values in the Midwest peaked this week because of the heat dome, high humidity levels have contributed to 'corn sweat' in these areas.
Corn sweat is a colloquial nickname for evapotranspiration, which is when plants, like corn stalks, release water vapor into the air and essentially turn it into additional humidity that can drive up humidity levels and heat index numbers in the area, according to the Weather Channel.
Today's weather term is "corn sweat".Yes, it's a real thing, and it's likely to become more noticeable into next week.Did you know that 1 acre of corn gives off about 3,000-4,000 gallons of water each day?Here's a little more about the transpiration process. pic.twitter.com/1k9S2gbG9Z
— NWS Sioux Falls (@NWSSiouxFalls) July 20, 2023
This mostly affects people in the Midwest, with residents in Missouri, Indiana, Iowa, Illinois and Kentucky experiencing heat index numbers in triple-digits because of the corn sweat, the Washington Post reported.
The corn sweat has also impacted these areas' dew points, which correlate to how much moisture is in the air, NWS explains. The higher the dew point, the more muggy and wet the air will feel.
A dew point minimum of 75 equates to an extreme humidity level and feels 'oppressive, like a tropical rainforest,' according to the Washington Post. In areas affected by the corn sweat, such as southern Missouri, the dew point is at 88.
Northeast, Midwest also warned about severe thunderstorms
AccuWeather meteorologists alerted on Wednesday that severe thunderstorms are expected to move across the Midwest before hitting the Northeast in the next few days. These storms carry the potential for high winds and hail, according to AccuWeather meteorologists.
The worst of the storms are expected to hit throughout Thursday afternoon and evening, mostly impacting cities like Chicago, Detroit, Oklahoma City and Kansas City, before shifting into the Northeast on Friday.
While it's rare to see precipitation happen within a heat dome, severe thunderstorms are likely to form around its edges, often called the 'ring of fire.'
"In the world of meteorology, the ring of fire deals with thunderstorms along the northern edges of strong upper-levels high,' AccuWeather meteorologist Bernie Rayno said. 'Oftentimes, this setup produces severe thunderstorms along the northern edges of the heat.'
How to stay safe in extreme heat
Extreme heat is the deadliest type of weather in the U.S., even more so than tornadoes, flooding or hurricanes, according to research by the NWS. Prolonged extreme heat, as is expected in the heat dome this week, is especially dangerous for people who do not have access to air-conditioning or who spend a lot of time outdoors.
If you live in a place that will be impacted by the heat dome, here's what to do to help protect yourself:
Stay indoors and cool for as long as you can. Here is a list of public places you can go to for free air conditioning.
Stay hydrated. It's helpful to add electrolytes to your water to further protect yourself from dehydration.
If you need to go outside, protect your skin by wearing sunscreen with an SPF of 30 or higher, sun-protective clothing and UV-blocking sunglasses.
Understand and look out for symptoms of heat-related illness. These include heavy sweating, fatigue, dizziness, muscle cramps, nausea and headaches. If you are experiencing these symptoms, move to a cool area to rest and hydrate.