While not a record, today's 99° high at Bush airport continues the heat beat that's making this month the hottest June on record. And there's more bad news ahead for the weekend. The large dome of high pressure will sit over us for the next few days keeping temperatures high. Here are the records for the next few days:
Fri - 100° (1902)
Sat - 103° (1934)
Sun - 101° (1980)
Even if temperatures don't break records, it will be plenty hot and it will feel oppressive. That's because we'll start to notice a slight shift in our wind to southeast. For most of the week, we've seen south and southwest winds, which typically mean the hot air is moving over more land than water. By Saturday, a steady southeast wind, coming off the Gulf of Mexico, will add more moisture to the hot air. Ironically, while the mercury may not climb into triple-digit territory, the heat index will.
This computed value takes the effect of more humid air to indicate how warm the air feels. Here's an example. On Wednesday, when we hit 100° and broke the record for the day, the dew point, a measure of the moisture in the air, was in the mid 60s. The heat index didn't rise too far over 101°. Now take Friday, when the temperature is expected to get to 100° but the dew points will be around 70°. That will make the heat index climb over 105°.
The more humid air becomes, the harder it is for very high temperatures to be reached. That's because the sun is heating not only the air, but also the moisture in the air. The same southeast winds that will increase the moisture will also keep temperatures in check. That's because high temperatures are more easily reached when the air is still. Moving air doesn't get as hot as quickly.
The bottom line though is that we all need to take it easy in this heat. If you have to be out, take frequent breaks and keep yourself hydrated. Once the heat index value reaches 100°, you are at risk of heat exhaustion.
There are signs of some relief by the middle of next week as the bubble of high pressure keeping us hot slides to our east, opening the door for abundant moisture from the western Caribbean and southern Gulf to head our way. Maybe relief won't be a mirage.