Central Pennsylvania is indeed bracing for a significant heat wave driven by a heat dome settling over the central and eastern United States. The National Weather Service (NWS) office in State College, which covers much of Central Pennsylvania, has already issued warnings.
A heat dome is a weather phenomenon characterized by a prolonged period of extreme heat caused by a strong, stationary high-pressure system in the upper atmosphere. This high-pressure system acts like a “lid” or “cap,” trapping hot air near the Earth’s surface and preventing it from rising and dissipating.
Here’s what Central Pennsylvania can expect:
- Extreme Heat Watch: An Extreme Heat Watch has been issued for Central Pennsylvania, including the Harrisburg and York areas, in effect from Sunday morning (June 22) through Wednesday evening (June 25). This indicates that conditions are favorable for a dangerous heat event.
- Dangerously High Heat Index: The NWS is forecasting “dangerously hot conditions with heat index values over 105 degrees Fahrenheit possible.” The heat index, or “feels like” temperature, accounts for both the air temperature and humidity, which will be significant due to the heat dome.
- Prolonged Event: This isn’t just a day or two of heat. The heat dome is expected to bring a multi-day heat wave, with the most significant heat and stifling humidity expected from Sunday through Wednesday.
- No Overnight Relief: A key characteristic of heat domes is that they inhibit overnight cooling. This means that nighttime low temperatures will remain very warm and oppressively muggy, offering little relief from the daytime heat. This can be particularly dangerous as the body doesn’t have a chance to recover.
- Increased Health Risks: The NWS explicitly states that the risk of heat-related illnesses will increase significantly during this period, with the highest risk on Monday and Tuesday. Vulnerable populations, such as the elderly, young children, outdoor workers, and those without access to air conditioning, are particularly at risk of heat exhaustion and heat stroke.
- Forecasted Temperatures: While specific forecasts can vary, general expectations for Central PA are temperatures in the 90s, with “feels like” temperatures exceeding 100 degrees Fahrenheit, and potentially reaching or surpassing 105 degrees in some areas.
What to do in Central Pennsylvania during this heat event:
The NWS and local authorities will be emphasizing vital safety precautions:
- Stay Hydrated: Drink plenty of water and other non-alcoholic, non-caffeinated beverages. Don’t wait until you’re thirsty.
- Seek Air Conditioning: Spend as much time as possible in air-conditioned environments. If you don’t have AC, visit public cooling centers (libraries, community centers) if they are opened.
- Limit Outdoor Activity: Avoid strenuous outdoor activities, especially during the hottest parts of the day (late morning through early evening). If you must be outside, take frequent breaks in the shade or in a cool place.
- Wear Light Clothing: Choose loose-fitting, lightweight, and light-colored clothing.
- Check on Others: Check on elderly relatives, neighbors, and anyone who might be vulnerable to the heat.
- Protect Pets: Ensure pets have plenty of fresh water and a cool, shaded place to rest. Never leave pets in parked cars.
- Know the Signs of Heat Illness: Be aware of the symptoms of heat exhaustion (heavy sweating, weakness, dizziness, nausea, headache, muscle cramps) and heat stroke (high body temperature, hot red skin, confusion, loss of consciousness). Seek immediate medical attention for heat stroke.
