The three H’s reign but relief is on the horizon
Hazy, hot, and humid…a pretty typical outlook for Fredericksburg weather in July. Given high temperatures today and tomorrow forecast to reach the mid-90s with dew points in the low 70s it will be steamy and very uncomfortable. The threshold for a heat advisory is a heat index (combination of temperature and humidity) of 105 degrees or more but NWS Sterling doesn’t think the ‘Burg will reach that level today but tomorrow may be different.
Meanwhile the stagnant conditions underneath the dome of hot air will lead to somewhat unhealthy air quality as shown in this graphic:
The grey shading indicates areas that are under an air quality alert, with the text indicating a “Code Orange” meaning air pollution levels may become unhealthy for sensitive groups such as children, the elderly, and others that have breathing challenges (asthma, lung disease, etc). Even though Fredericksburg is not officially under such an alert the city and vicinity are not far outside this unhealthy air zone so please take note.
The heat will continue through Friday and most of Saturday but the cavalry is on the way in the form of a cold front that will cool things off starting Sunday. Under the continuing anomalous weather pattern another in a series of unusually strong (for summer) long wave troughs will push a surface cold front through and south of our area over the weekend. The three H’s will break down as a result and high temperatures will drop back into the mid and upper 80s behind the front through the early part of next week. In fact the Climate Prediction Center shows much of the Mid-Atlantic likely to be cooler than normal for a week or so after this next cold front.
The catch is that these hot spells don’t go quietly into the night. The cooler dryer air associated with the front will crash into the existing heat dome and create conditions for some strong to severe thunderstorms over the weekend. Stay tuned for more on that as the weekend approaches.