Dangerous heat wave to impact Delmarva this week: What to know

An intense early summer heat wave will peak through the middle of week, with near-record temperatures across Delmarva. Monday and Tuesday stand to be the hottest days with high temperatures expected to be near 100. Max feels-like temperatures will average 105-110 across much of the area through Wednesday. Heat Advisories are in effect with an Excessive Heat Watch posted for the lower shore.

The “heat dome”

High heat and humidity can sometimes lead to cooling thunderstorms in the afternoons. But when a “heat dome” builds in the upper levels of the atmosphere, the chance for rain is slim to none. A high pressure system is one that creates a sinking air environment. At the surface, this suppresses cloud development as a result. On a hot day, the rising air can break through this suppressing “cap” and create cooling clouds and sometimes thunderstorms. A “heat dome” is simply high pressure on top of high pressure. When high pressure builds aloft, it adds another layer of air suppression, limiting not only the chance for rain, but little to no cloud development.

Dangerous “feels-like” temperatures

Heat waves can occur with or without humidity, but it’s the humidity that makes a heat wave exceptionally dangerous. With our proximity to the coast, this is the most common type of heat wave we experience on Delmarva. High humidity makes it harder for the body to cool itself, and we use the “feels-like” temperature to depict this impact on our bodies.

Courtesy: National Weather Service

Feels-like temperatures near populated areas like Salisbury and Georgetown will be even higher due to the urban heat island effect. The worst heat will occur through Wednesday with some relief by later in the week as the heat dome breaks down. Slightly cooler air aloft will be allowed to mix down to the surface, along with a better chance for afternoon clouds and potentially some rain.

No relief at night

High humidity limits the air’s efficiency to cool at night. This makes high humidity heat waves that much more dangerous, because our bodies do not get the opportunity to recover from the daytime heat. Overnight low temperatures can struggle to fall through the 70s, and in the more urban areas the temperature can remain above 80 for much of the night. This can enhance the risk for heat exhaustion or heat stroke as a heat wave becomes prolonged.

Courtesy: NOAA

Danger to our four-legged friends

Like humans, dogs and cats are susceptible to the dangers of a high heat environment. Simple, but critical, action can be taken to protect your pets if they are outside. Provide plenty of water and areas of shade that can be easily accessed. Never leave a pet unattended in a car. And avoid stressful activities, like walks, during the hottest times of the day. When walking your pet, avoid the higher sun angle times of the day. Concrete and blacktop temperatures can reach 120-140 degrees in the midday sun. Getting the walk in during the early morning or later in the evening is the safest for your pets – and for you!